The Two Best Ways to Build Endurance as Fast as Possible (without Destroying Your Body)

He's an expert in human performance and nutrition, voted America's top personal trainer and one of the globe's most influential people in health and fitness. His show provides you with everything you need to optimize physical and mental performance. He is Ben Greenfield.

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Welcome to Chapter three of Beyond Training. You'll find all the resources for this chapter over at BeyondTrainingBook.com chapter three that's BeyondTrainingBook.com chapter three we're going to start.

With the black Hole.

There's a big, big problem in endurance sports.

It's a hole, a black hole.

And the black hole goes something like this. The runner who rolls out of bed.

Three to five days a week to.

Run 45 to 60 minutes at the same speed every time. The triathlete who hops in the pool at lunchtime and swims 30 minutes steady every time. The cyclist who goes out every weekend and rides at a steady cadence and speed for the same two hours every time. Same speed, same rpm, same intensity, day after day, month after month, year after year. Perhaps it's the thumb sucking solidarity we find in knowing exactly what our bodies are going to feel like during training session. Perhaps it's the fear of going too slow or too hard and somehow messing up our training or our bodies. Or perhaps it's simply not knowing what to do and simply figuring something is better than nothing. Or perhaps we're just lazy. That's right, disguised behind all our spandex, fancy bikes, Speedos, expensive shoes and complicated training gadgets, we could just be lazy. After all, compared to doing 30 minutes of hard focused run intervals, it's easier to simply head out the door and slog through a mind numbing two hour death march compared to doing a structured.

Series of swim drills.

It's easier to just hop in the water, turn the brain off and stare.

At the black line for a while.

Rather than doing a series of intense interval based hill climbs. It's easier to simply point the bike in one direction, hunch over the handlebars and spin the pedals at whatever feels like a halfway decent pace.

Yes, I said it.

We hard charging, type A obsessive compulsive exercisers could just be lazy. And regardless of whether it's sticking too close to the tried and true fear of failure or injury lack of training knowledge or pure laziness. Endurance athletes and athletes in general simply accumulate the majority of training time at one single speed. The not too hard, not too easy, slightly near threshold training zone that makes you feel like you're working kind of hard but not too hard and perhaps just hard enough to get you a little bit fit. I call it black hole training. This training flaw has even been demonstrated in studies. For example, despite what a coach's training plans may dictate, runners tend to run too hard on easy days and two easy on hard days. Suddenly, training sessions that are supposed to be long and slow become fast and short. Workouts that are supposed to have variations in pace instead get performed at one single speed. As a result, most training sessions end up being performed at the identical intensity workout after workout, and the athlete winds up racing at the same speed season after season. You may also be familiar with this type of training as junk miles or single speed or no man's land training. And in the previous chapter I alluded to it as perhaps just too much time spent in heart rate zone 3. Just hard enough to deplete energy levels and damaged muscles, but not quite hard enough to elicit any significant training response. In a bicycling magazine article back in the 90s, cycling journalist and coach Fred Matheny describes it this no man's land workouts provide a kinesthetic sense of working hard, but expose the rider to too much stress per unit gain. Instead, most base training should be guilt producingly easy and the top end high intensity training should be very mentally hard, not sort of hard. Simply stressing the same energy system over and over again not only results in a single speed endurance athlete who can't go fast enough when it matters and never goes slow enough for recovery, but may also result in more rapid onset of overuse injury from repeated stress on the same joints. For example, research shows that 10 to 15% of the population is predisposed to something called femoral acetabular impingement which can lead to labral hip tears and hip arthritis when coupled with a sport like say triathlon which includes a high amount of hip jarring flexion during running and cycling. Based on this, who do you think is going to have the higher risk of hip replacement? The triathlete who does every training session at the same speed, often on the same course using the same joints and energy systems time after time? Or the triathlete who mixes things up with some trail running, some track work, some hill work, some lateral movement, some cross training and some recovery workouts well, stressing the same energy repeatedly also results in very high amounts of negative energy balance, especially when the majority of the training is done at or near what's called threshold, which you're about to find out is not the case with most pro athletes, but is the case in many recreational exercisers. Studies have shown that this negative energy balance or negative calorie balance results in hormonal disruption like testosterone deficiency and low libido in males, estrogen deficiency and low bone density in females, a wildly out of balance secretion of appetite disrupting hormones, and a host of other endocrine and chronic disease related health issues. I'll put a link to some of this research in the reference webpage for this chapter. This is yet another reason that junk miles just aren't worth it. But wait, what about the stories of Kenyan marathoners and elite endurance athletes going out and completing long, slow training sessions with hour after hour at a single speed? Isn't that black hole training? Isn't that no Man's Land style junk miles performed at a single speed? If so, it certainly seems to be working for those folks, right?

Well, the fact is, that type of.

Training you might be thinking of is actually not black hole training. It's something completely different. And you're about to learn what that is, why it's much different than black hole training, and why it's one of the two best ways to build endurance. Let's start with something called the Pareto Principle. When you look at the training protocols of most elite endurance athletes, who typically train with 10 to 12 workouts and 15 to 30 hours each week, a distinct pattern emerges. Specifically, those elite endurance athletes spend about 80% of their training time below and about 20% of their training time above.

Their lactate threshold, which I referred to.

As Zone 4 in the previous chapter. While this 8020 pattern is so prevalent, there's even a special name that has emerged in exercise science to describe it. It's called polarized training. When you look at endurance athletes from world champion rowers, professional marathoners, elite cyclists and high level triathletes, nearly all the top athletes competing in these sports are engaging in this kind of polarized training in which they perform a large amount of time at relatively easy aerobic intensities and occasionally throw in extremely hard bursts of high intensity. And these athletes are spending very, very little time in this black hole region. That zone where you're training above an easy aerobic pace, but below any pace becomes extremely uncomfortable. Well, you may already be familiar with this 8020 concept as the Relatively famous Pareto principle, which states that for many events, approximately 80% of the effects comes from 20% of the causes. For example, one study quantified the training intensity distribution of professional swimmers over an entire season and found these athletes swam about 77% of their swimming. That's close to 80% over the entire season at a purely aerobic intensity. Another study investigated marathoners and found that during the 12 weeks leading up to the Olympic marathon trials, These athletes ran 78% of their training at below marathon speed, only 4% at their race speed, and 18% above threshold. And what about those Kenyan marathoners I alluded to earlier? Another study found that elite male and female Kenyan runners train with about 85% of their weekly training volume completely in an aerobic zone below threshold. The evidence goes on and on. For example, another study looked at a group of sub elite distance runners who are randomly assigned to one of two training groups. Group one performed about 81% of their training in an easy aerobic zone one, 12% of their training in a moderate zone two, and 8% of their training in a zone three. Now don't get confused here. They were simply using three zones to quantify training intensity rather than the five zones I used in the previous previous chapter. So again, 81% of their training aerobically, 12% of their training in a moderate zone, which would be called that black hole area, and 8% of their training in high intensity. In contrast, Group 2 performed more threshold training with 67% easy, 25% moderate, and only 8% high intensity. In other words, Group 2 performed twice as much of their training at or near their threshold. Interestingly, the authors reported that the athletes were not even able to exercise any more than about 8% of their time in a high intensity zone as it was simply too hard.

That should give you a good idea.

Of how hard high intensity interval training is really supposed to be. The total training volume was identical between the two groups.

But guess what?

After five months of this protocol, the running performance of Group 1 was significantly higher, despite the fact that they had spent a great deal of time exercising at a much lower intensity than group two. But that wasn't an isolated study. In more research, a group of rowers were split into two different training groups. One group was a low intensity group that performed nearly all their training below 75% VO2 max, which is a relatively low intensity. Meanwhile, the other group, called the mixed intensity group, performed 70% of their training at those same low intensities, but did the other 30% of their training at a much higher intensity above lactate threshold. These two groups also performed nearly identical volumes of training. And despite a significantly higher amount of training at a high intensity above threshold, the mixed intensity group didn't perform any better than the predominantly low intensity group. Sure, after 12 weeks of this protocol, both groups had improved performance and higher maximal oxygen consumption. But even though they spent a significantly higher amount of time at that time black hole training zone, that mixed group didn't have a significantly greater gain in performance. Well, that's a big bummer for the mixed intensity group. So the takeaway message so far is this. Across a wide range of sports, studies have shown that the best endurance athletes are actually performing about 80% of their training volume at a low intensity and about 20% of their training at a high intensity. And those high intensity efforts are indeed very very high, with relatively little time spent in no man's land black hole style training zones where most recreational athletes train. These athletes are getting enough low intensity training to build big aerobic engines and get lots of repetitions to ingrain correct movement patterns for improving their movement efficiency and economy while also exposing themselves to just enough hard stress for significant cardiovascular and muscular adaptation. So why, if lots of low intensity training is good, wouldn't more be better? In other words, instead of 80 20, why not 90, 10, 95.5 or even 1000 when it comes to training intensity percentage distribution? Well, it turns out that multiple studies, especially in elite athletes, have investigated what happens when mild doses of high intensity interval training are added to an already primarily aerobic training protocol and the results are always favorable and not surprisingly, always close to no more than about the 20% mark with the high intensity dosing. Someone named Steven Seiler sums this all up quite nicely in a paper that appears in the International Journal of Sports Physiology and Performance and here's a quote from that journal. Numerous descriptive studies of the training characteristics of nationally or internationally competitive endurance athletes training 10 to 13 times per week seems to converge on a typical intensity distribution of which about 80% of the training sessions are performed at low intensity, with about 20% dominated by periods of high intensity work such as interval training. At approximately 90% VO2 max endurance athletes appear to self organize towards a high volume training approach with careful application of high intensity training incorporated throughout the training cycle. Training intensification studies performed on already well trained athletes do not provide any convincing evidence that a greater emphasis on high intensity interval training in this highly trained athlete population gives long term performance gains. The predominance of low intensity Long duration training in combination with fewer highly intensive bouts may be complementary in terms of optimizing adaptive signaling and technical mastery at an acceptable level of stress. So despite the fact that it feels very rewarding to roll up your sleeves and head out the door to hammer at or near your threshold or in that black hole zone for a morning or lunchtime run, or ride at a steady race pace, intensity for a few hours on the weekend, or swim lap after lap in the pool at one single medium intensity, it's simply the wrong way to train. Now, there is what's called the regression problem. In all fairness, it's pretty darn difficult to go easy when you're supposed to go easy and go really truly hard when you're supposed to go hard. For example, the study I referenced earlier tried to replicate the polarized training of successful elite endurance athletes with a program designed around more threshold training. But this time they tried that same protocol on recreational runners rather than elite runners. Now, the intended intensity distribution for the two training groups was supposed to be 77% low intensity, 3% moderate intensity, and 20% high intensity. And that was supposed to be compared to another group that did 46%, 35% and 19% in contrast. Now, interestingly, that second percentage recommendation was based on the American College on Sports Medicine recommended training intensity distribution. But heart rate monitoring during the study revealed that the actual intensity distribution achieved by the recreational runners was 65%, 21% and 14%. And the 31%, 56% and 13% intensities were what was experienced in the threshold training group. Now, I know that's a lot of numbers, but let me put it this way. When we compare the intended intensity and the actual achieved intensity distributions in this study, what it highlights is that when left to choosing our own training intensities, we tend to aggress toward black hole style training, even if we're instructed to do otherwise. Now, hard exercise of any sort creates free radicals that causes some damage called oxidation to your muscles, cells and organs. And as your body repairs this dam, you experience biochemical adaptations that make you more resistant to future oxidative damage from high volume or high intensity training. And then, as you train more, your body simply increases its production of natural antioxidants to control the free radicals you're producing. Now, based on this enhanced repair mechanism and surge in natural antioxidants that occurs in response to tough workouts, it would seem to make sense that doing long sessions of black hole style training may actually result in making you fitter and faster, right? However, Although consistent oxidative stress is a critical component of getting fit, you must allow for a recovery period during which the body can bounce back adequately, and the key is to train in a manner that provides enough physical stimulus for you to get more fit without causing overtraining or excessive oxidative stress. Rather than exposing the body to the same amount of stress and intensity day in and day out, you'll allow for enhanced free radical fighting capacity by engaging in some very hard days and some very easy days. My friend Army Legg sums this up quite nicely in his article at improveism.com, which I'll link to in the webpage for this chapter. And the name of this article is called the Truth About Extreme Exercise, Oxidative Stress and you'd Health. He puts it this way, most evidence indicates that if you train in a progressive, intelligent manner with adequate recovery between workouts and you can build up to extremely high training loads, you can still be protected against the potentially dangerous levels of oxidative stress. So the key there is what Armie mentioned about adequate recovery between workouts and there's a big difference between low intensity spread throughout the day or spread throughout a week, small amounts of high intensity and very adequate recovery periods compared to simply going out every single day and training at the same pace and the same intensity. Well, that should about wrap it up, right? I mean, after all, it turns out that this seems to work quite well to use this whole maffetone style method of finding your easy aerobic fat burning training zone and then spending a great majority of time training in that zone with brief spurts of high intensity. I guess Mark Allen was onto something after all when he won those six Hawaii Ironman World Championship Triathlon titles using this strategy. And it would seem that we now know the ultimate way to build endurance.

End of story. Well, hold your horses.

I don't know the last time you peaked at the training log of an elite endurance athlete such as a marathoner or Ironman triathlete, but you've already heard that they train 10 to 15 times per week. That's not hours per week, that's times per week. And most Ironman triathletes, for example, are swimming 20 to 30,000 yards plus per week.

That's about six to eight hours.

They're also cycling 150 to 250 miles a week. That's another eight to 10 hours. They're running 25 to 40 miles a week.

That's another four to six hours.

Not to mention the additional hours spent core training, weight training, recovery training and of course the additional hours spent preparing and eating the thousands of calories necessary to fuel these monster amounts of training volume. And don't think this type of volume is isolated to those crazy ironman triathletes, competitive marathoners, elite cyclists, top level swimmers, and all other professional endurance athletes in particular, literally devote their life to training. And my question for you is this. Do you have 25 to 40 hours per week to train and do you have the self control necessary to hold back the reins and ensure that 80% of this training is in a very easy aerobic intensity zone? If so, then proceed with polarized training. But proceed with the knowledge that the majority of current training methods for endurance events like an ironman or marathon are derived from the training schedules, calendars and lifestyles of predictions professional endurance athletes who compete in the sport for a living and have 25 to 40 hours to train in a given week. And that means that if you have a busy life, a steady income, social obligations, kids, a nightlife or other hobbies, this style of polarized training may require you to potentially neglect your friends, career, family and life. And for me personally, this all relates to the lens that you see the world through. Who cares if the training protocol works.

If it's bad for you or sucks.

Time away from your career, friends and family? Unless you are a professional athlete and this sport is how you're making money, getting your paycheck, feeding your family, then your precious time may possibly be better spent elsewhere. But that's your personal call. Some recreational athletes do indeed have high disposable incomes, careers that are on cruise control, or the time to devote to 80% low intensity, 20% high intensity polarized training, which works when you have many, many hours per week to train. Or perhaps you're just the kind of person who thrives on being by yourself and spending long amounts of time training. If so, polarized training is indeed one of the best ways to build endurance as fast as possible without destroying your body. But as I alluded to in the title and the opening to this chapter, there is one other training method to build endurance properly, and you're about to discover what that other training method is. Before we jump in to that next training method, remember, all the resources for this chapter are over@beyondtrainingbook.com Chapter 3 welcome.

To Chapter 3, Part 2 of Beyond Training. Now, before we delve into how to build endurance without putting in dozens of hours of training each week, it's going to be important for you to understand how your body actually builds endurance and what the primary determinants of cardiovascular and endurance performance actually are. Your cardiovascular performance is based on three primary variables. Your heart rate, or how many times your heart beats per minute, your stroke volume, or the amount of blood pumped per heartbeat, and your heart contractility, or the forcefulness of each actual contraction of your heart muscle. As each of these variables increase, the amount of blood flow and oxygen supply to your exercising muscles also increases. So, at first glance, it would seem that the heart is the primary thing you need to worry about when it comes to athletic training. And aerobic training has certainly been proven as one of the best ways to improve all of the variables that I just described. Heart rate, stroke volume, and heart contractility. But there are important determinants of sports success that go above and beyond simply your heart. For example, when your muscles contract, they propel the flow of blood traveling through your veins and back to the heart, which increases the amount of blood filling your heart. This is called a preload. This preload actually enhances the heart stroke volume during exercise, making adequate contraction and strength of your skeletal muscle a major determinant of your endurance performance. So, at first glance, it would seem that the heart is the primary thing you need to worry about when it comes to endurance training. And aerobic training has indeed been proven as one of the best ways to improve the variables that I just described. But there are important determinants of endurance success that go above and beyond simply your heart. For example, when your muscles contract, they propel the flow of blood traveling through your veins and back to the heart, which increases the amount of blood filling your heart. And this is called a preload. The preload actually enhances the heart stroke volume during exercise, making making adequate contraction and strength of your skeletal muscle a major determinant of endurance performance. And that's not all. Tiny powerhouses in your cells, called mitochondria, use oxygen to manufacture high levels of ATP energy via the breakdown of carbohydrates or fat. So if you increase your mitochondrial density, more energy becomes available to your working muscles, which allows you to produce higher amounts of force for longer periods of time. In addition, your actual VO2 max, or the maximum amount of oxygen you can deliver to your muscles in a given amount of time, is a result of two variables. Number one, how much blood your heart can send to your muscles, which is a combination of the heart rate, stroke volume, and heart contractility that you already learned about. And number two, how much of the oxygen sent to your muscles is actually extracted from the blood and used by the muscles before the Blood heads back to your heart. Now, that second variable I just described depends on oxygen delivery to active muscle fibers. And this is influenced by everything from blood flow distribution to capillary density to arterial oxygen content to local enzyme adaptations to the number and density of the mitochondria. So the important question is this. If you want to optimize your heart capacity while at the same time increasing the number and density of your mitochondria, raising your VO2 max and strengthening your skeletal muscles for higher force production and better venous return to your heart, is there anything comparable to or superior to long, slow aerobic training? Well, the answer is an unequivocal yes. And this is where HIIT enters the picture. HIIT is the acronym for High Intensity Interval Training. Now, don't shudder too hard. It's not as bad as it sounds. I'll explain in just a bit what HIIT involves and how you can intelligently implement HIIT into your training without hurting yourself. But first, I want to talk to you about the proven power of how HIIT can influence the components of the endurance success that I already described. So let's start with your mitochondria. For years, exercise scientists have been convinced that the only way to increase mitochondrial density is with aerobic endurance training. But recent studies have proven otherwise. Not only is an increase in the size and the number of the mitochondria a proven adaptation to hiit, but the mitochondrial benefit of HIIT goes way above and beyond just the size and the number. For example, all your mitochondria contain enzymes like citrase synthase and malate dehydrogenase and succinate dehydrogenase. And these oxidative enzymes lead to improved metabolic function of your skeletal muscle, particularly by causing more effective fat and carbohydrate breakdown for fuel and also by accelerating energy formation from ATP. So more of these enzymes means you have a higher capacity for going longer and harder. And it turns out that an initial study on the effect of HIIT training on oxidative enzymes demonstrated massive increases in skeletal muscle enzymes in people engaged in seven weeks of intense cycling sprints. In this case, 4 to 1030 second maximum cycling sprints, followed by 4 minute recoveries on three days per week. Now, what about HIIT versus aerobic cardio? Well, another six week study compared the increase in enzymes that resulted from either 4 to 630 second maximum effort cycling sprints with 4 to 5 minute recovery.

Bouts 3 days per week.

That's a classic HIIT training protocol, or 40 to 60 minutes of steady cycling at 65% intensity five days per week. The levels of enzymes in the mitochondria among the subjects who performed the HIIT program were significantly higher, even though these folks are training at just a a fraction of the volume of the aerobic group. So how could this favorable adaptation happen with such short exercise periods? Well, it turns out that the increased mitochondrial density and oxidative enzyme activity from HIIT is caused by a completely different message signaling pathway than traditional endurance training. In this alternative pathway, a master switch is activated that promotes favorable endurance adaptation. This master switch is known as PGC1alpha, which stands for Peroxisome Proliferator Activated Receptor G Coactivator 1alpha. But you don't have to know all of that unless you really want a way to impress your friends. PGC1 Alpha causes that favorable increase in mitochondrial density and enzyme activity, but it can be activated by two completely different pathways. One pathway called a calmodulin kinase pathway, or one pathway called an adenosine monophosphate kinase pathway. One's called the CAMK pathway, and that second one's called the AMPK pathway. Well, continuous endurance training seems to activate the master PGC1 Alpha switch via the former pathway, the CAMK pathway, while intense interval training activates it via the latter pathway, the AMP K pathway. Conveniently, this increase in enzymes can actually change your metabolism, causing you to shift into higher fat oxidation during exercise. This may seem a bit ironic since high intensity interval training actually burns a higher percentage of carbohydrate as a fuel while you're doing the actual intervals. But multiple studies have proven that after just a few weeks of hiit, your fat burning becomes significantly higher and your carbohydrate burning becomes significantly lower. So with HIIT training, you become a metabolically efficient fat burning machine in far less time than it takes to accomplish the this same effect through long aerobic sessions. But these benefits go above and beyond what you burn during your actual workout session. For example, many endurance athletes are interested in weight loss, although we affectionately call it improving our power to weight ratio rather than burning some fat off of our ass. The good news for those of us who want this improved power to weight ratio is that in addition to shifting your body into higher fat oxidation during exercise, HIT also increases your post exercise oxygen consumption. That means after a hard interval based workout, your oxygen consumption and thus the total amount of calories you burn after the actual workout remains elevated as your working muscle cells restore physiological and metabolic factors in your cells to their pre exercise levels. Now, in a review article of studies that have been done on hiit. It was found significantly higher EPOC or post exercise oxygen consumption exercises with HIIT training compared to continuous aerobic training, which translates into higher and longer calorie burning long after your workout is over and month after month this calorie burn significantly adds up. Now let's see what HIIT can do to your VO2 max, which is your body's upper limit for consuming, distributing and using oxygen for energy production. In one study, four repetitions of four minute runs at 90 to 95% of heart rate max followed by three minutes of recovery performed three days per week for eight weeks resulted in 10% greater improvements in stroke volume compared to long slow distance training three days per week for eight weeks. Remember that stroke volume is one of the key components of your body's ability to deliver maximum oxygen to working muscles. Another study showed that high intensity intervals performed at 90 to 95% of VO2 maximum max increased left ventricle heart mass by 12% and cardiac contractility by 13%. And these are two other significant determinants of cardiovascular capacity and oxygen delivery during exercise. Another study measured the increase in VO2 max among subjects who performed eight weeks of either HIIT or continuous aerobics. And as you'd probably expect by now the increase in VO2 max was significantly higher in the HIIT program, 15% actually, compared to 9% in the aerobic endurance group. Since increasing cardiovascular function in VO2 max are two major ways to help patients with cardiovascular disease, even cardiac rehab facilities are catching onto the idea of HIIT training and are beginning to include this style of training for heart disease patients. Even though traditional low intensity aerobic exercise can definitely improve heart disease risk factors, these same improvements from interval training happen in a shorter time with fewer sessions. Now, how about your muscle? Well, as you learned earlier, when your muscles contract, they propel blood back to your heart, which increases the amount of blood filling your heart and the heart's subsequent stroke volume. Within just one to two days of hiit, tiny blood vessel changes begin to take place in your skeletal muscle that improve the flow of oxygen in and out of the muscle and a better match in terms of oxygen delivery to oxygen utilization. These adaptations are accompanied by an increase in the strength of the muscle, which allows for even more forceful pumping potential. In addition to improving the force and the contractility of skeletal muscle fiber, HIIT also significantly lowers insulin resistance and results in a number of skeletal muscle adaptations that cause enhanced muscular fat oxidation and improved glucose tolerance. Yet another method by which HIIT can turn you into a fat burning machine. These are skeletal muscle benefits of hiit, which I've personally discovered that go above and beyond what you may find in research studies. For example, when I've exposed my body to pain cave style workout sessions like hard cycling intervals, I'm not only able to dig mentally deeper, but also less likely to experience protective muscle spasms or cramps. Well, that makes sense, since Tim Noakes, among other exercise scientists and physiologists have suggested that much of the cramping that athletes experience during a race or an event may in fact be due to the fact that people are calling upon their bodies to do something during a race that their bodies simply haven't been exposed to during training. For example, if your quadriceps muscles have rarely been exposed to say, 350 watts of power on a bike and you call on them to produce that amount of power when you attempt to pass someone or surge during a race, they may simply respond by rebelling and going into a protective spasm. And as your quads curl up into a thumb sucking fetal position, you can throw back all the salt capsules you want. But it's not going to help if it has nothing to do with your hydration status and everything to do with how you actually trained. So it would seem that HIIT is the ultimate solution for people who have limited time to train and can't engage in the hours necessary for the polarized training approach that I talked about in part one of this chapter. But are there problems with hiit? Well, you bet. First, there's benefits which you derive from long endurance training that you just can't touch with HIIT. For example, researchers at University of Western Ontario had 20 volunteers perform six weeks of training three times a week. One group ran steadily at an easy aerobic intensity of 65%, starting with 30 minute runs and building up to 60 minute runs, while the other group did 30 second sprints with four minute recoveries, starting with four sprints and working up to six. As expected from what we already know about HIIT, the sprint group increased their parameters of endurance performance as much or more than the easy aerobic group. Both groups increased their VO2 max by around 12%, both groups increased their 2K run time by around 5%, and both groups lost fat, although the HIIT group did lose twice as much fat. But when researchers measured maximum cardiac output, which is a measurement of the largest amount of blood your heart can pump in any given amount of time, the aerobic group actually increased theirs by almost 10% while the sprint hit group didn't experience any increase in maximum cardiac output. So what this study tells you is that to get the most bang for your buck from your endurance training, you not only want to maximize how much blood that your muscles can utilize with HIIT training, but you also want to maximize how much blood your heart can send to your muscles with aerobic training. And so you have to include some semblance of long steady workouts in your training program, just less than what most people do. In other words, hiit works more effectively on your peripheral muscle fitness, while endurance training works more effectively on your cardiovascular fitness. So now that you know the benefits of HIIT and when you need to do it, let's jump into something called CrossFit. Because the HIIT approach is overdone by many people and these training enthusiasts get exposed to the same kind of evidence you've just heard about, but they take things to kind of an unhealthy level. While I'll be one of the first to endorse HIIT as an ideal time effective way to build a big endurance engine, there's a definite limit to how much of this type of training you can do before it begins to cripple you. Beating up your joints with excessive high impact and loading, depleting your hormones as you sprint from a lion every day and leaving you mentally frayed from having to repeatedly dig dip into the training pain cave. In the same way that black hole training can leave you exhausted, skinny, fat or overtrained, too much time spent top end training can have a similar effect. And when it comes to HIIT, more is definitely not better. We can use CrossFit for an example of this. Now, CrossFit is an extreme exercise program designed to improve core strength and functional fitness through the use of strategies like Olympic weightlifting, kettlebells, gymnastics rings, pull up bars and a a wide variety of body weight moves and calisthenics. So a typical workout might include running, rowing, rope climbs, jumping onto and off of boxes, flipping big tires, carrying heavy operational gear, or bouncing medicine balls against the floor or wall. Now, typically these workouts are done in a group setting with an instructor. And a great deal of emphasis is placed on beating those around you, outperforming your peers and pushing yourself to failure. So Examples of daily CrossFit workouts include routines like like 3 rounds for a time of running, 800 meters with a 45 pound dumbbell, 15 foot rope climb, 3 ascents, 135 pounds of the thruster exercise for 12 reps, or complete as many rounds as possible of 10 pull ups 75 pound dumbbell deadlifts for 5 reps and 135 pound overhead push press for 8 reps or do 5 rounds for time of 135 pound of deadlift for 9 reps, 135 pounds of the power snatch for 6 reps and 135 pounds of overhead squat for 3 reps. Now CrossFit endurance is a hybrid method of CrossFit training designed specifically for endurance athletes and According to the CrossFit Endurance website, they have triathletes work up to a weekly schedule that includes four days of CrossFit training, three strength training days and two days each of sports specific training for swimming, biking and running. Now as you can see in a link that I'll have over at the reference website for this chapter@BeyondTrainingBook.com the workout of the day in a CrossFit endurance program is pretty much very similar to a regular CrossFit workout, but with extra swimming, cycling and running thrown in. Now don't get me wrong, CrossFit can definitely get you fit and has indeed been proven to increase your VO2 max. As a matter of fact, a very recent study found that 10 weeks of CrossFit based high intensity power training significantly increased VO2 max and body composition. Granted, a whopping 16% of the total recruited subjects had to drop out citing overuse or injury and there are many emerging reports of increased rates of musculoskeletal injury and metabolic derangement from these type of programs. Now I've personally done many CrossFit workouts and I have my own personal suspicions about why this injury and overtraining potential might might be the case with CrossFit or any program that throws too much high intensity interval training into the mix, especially when combined with hard weight training. First, Olympic weightlifting and many of the other moves performed in a workout like CrossFit require a lot of attention to proper technique and should ideally be performed with a low number of repetitions, good form and not necessarily in the presence of the complete physical exhaustion that distracts you from good form. This is simply not the case in many triathletes or endurance athletes who are combining say high repetition snatches or heavy clean and jerks with sprinting, tire flips and rowing, especially for individuals who are new to a program like this or simply jumping in and replicating or attempting to beat what their peers are doing during the workout. Next, having a set number of reps that you must complete four time like as many rounds of rowing, push, press and pull ups as you can do in 20 minutes, forces many type A athletes to push themselves harder than they might normally go without necessarily listening to the body's natural warning signs to slow down or stop. And this can often result in forcing the body through a particular range of motion, even if the supporting musculature for that range of motion is fatigued. And when you're subjecting your joints to the strain of hammering in and out of an exhausted, poorly performed overhead press or a swinging ballistic pull up, it should come as no surprise when the shoulders begin to grind and hurt during, say, a swim workout the next day. Next the majority of HIIT studies show that HIIT tends to be efficacious without high injury dropout rates when HIIT is used infrequently with small and potent doses spread sparingly throughout the week, in contrast to the frequent, often daily CrossFit style exposure to intense intervals combined with heavy weight training. For example, when I was at the 2010 USA Triathlon Art and Science of Triathlon Coaching Symposium, a HIIT researcher named Steven McGregor introduced a HIIT training routine that's been shown in research to lead to incredibly significant increases in power output, peak power and VO2 max. It goes like this. You start with four 30 second maximum sprints with two to four minutes of rest after each sprint, and you do that just three times a week. And then you gradually decrease your rest periods until you're resting just two and a half minutes maximum after each 30 second sprint. Now you do this for seven weeks for a total of 6.5 to 15 minutes of actual HIIT per week. That's not much, but despite this minimalist, high quality approach, many people who are implementing HIIT into their training routines, including crossfitters, are easily doing twice the volume I just described. Not just in a week, but in a single day. Finally, getting your time in the gym should primarily be spent getting strong and developing clean and functional movement patterns that enhance balance, symmetry and stability, and not necessarily building your muscular and cardiovascular endurance or trying to compete for time or points while simultaneously pushing through soreness and fatigue. This is a concept that I write about extensively in my book Weight Training for Triathlon, the Ultimate Guidebook. In that book I mentioned that high amounts of metabolic conditioning that you may experience while swimming, bicycling or running can become very easy to pile even more excessive metabolic stress on when more of this same type of conditioning is experienced in a gym setting. So instead, the way I like to think about it is this. Use the gym for strength and work on endurance elsewhere. So ultimately, here's the problem with CrossFit. If the highly anaerobic and power strength demanding CrossFit workouts are performed in a typical carbohydrate depleted state by a triathlete or endurance athlete who is engaging in heavy amounts of aerobic training simultaneous to CrossFit involvement, the result is poor form and increased risk of injury during the actual CrossFit routine combined with sacrificed biomechanics and hormonal imbalances from CrossFit induced soreness and fatigue during any subsequent aerobic swim, bike or run sessions. In other words, aerobic athletes and triathletes can't have their CrossFit cake and eat it too. And I guarantee that if you're doing a proper CrossFit program and combining it with a proper triathlon endurance training program, there's absolutely no chance that you're giving your testosterone cortisol ratio or inflammatory response to exercise an adequate time to recover, which results in lowering of your immune system, excessive loading of soft tissue and joints, and increased risk of overtraining syndrome. And perhaps it's just a consequence of the type of self quantified crossfitters who are going out of their way to test their blood mark but as a wellness practitioner for WellnessFX, I see the biomarker values of many, many CrossFitters each week and they tend to be some of the most hormonally depleted and beat up folks for whom I consult. And if you don't want this type of hormonal melo to result in adrenal fatigue, then my first piece of advice is to back off something like CrossFit and add in more recovery sessions, easy swims, yoga, sleep, rest and maybe even a little extra calorie intake. So can you do a program like CrossFit right and avoid adrenal fatigue? Well, absolutely. There's fantastic CrossFit coaches who design workouts and training routines with specific strategies to allow for proper rest and recovery and good attention to form without pressure on participants to completely bury themselves on five, six or seven days of the week as some kind of a badge of honor. And there's actual attention paid to elements like tissue quality, mobility, technical proficiency, proper progression of workouts and proper movement patterns. A really good book if you want to do CrossFit the right way in this manner, is written by Brian McKenzie and it's called Power Speed Endurance. But in many cases CrossFit can serve as a perfect example of how HIIT training can be overdone if you're not careful. So now that you know that if you have lots of time on your hands, you can build endurance effectively by performing 80% of your training in a very easy aerobic zone and 20% of your training in a very hard anaerobic zone. That's called, if you recall, polarized training. And the biggest mistake most people make with this approach is not doing the easy 80% easy enough and not doing the hard 20% hard enough. So how can you do polarized training the right way? Well, I'm not great at math, so let's use a simple weekly training volume number to work with. Let's say 20 hours. Begin by allocating 80% of those 20 hours, which is 16 hours to easy aerobic training. If you want to know how to find out what your aerobic training heart rate zone is, then go Back to chapter one or use the 180 minus age formula which goes like this. Subtract your age from 180. Modify this number by selecting from one of the following categories that best matches your fitness or health profile. If you have or recovering from a major illness or on any regular medication, subtract 10 beats from that 180 minus age. If you're injured, you've regressed in training or competitions, you get more than two colds or bouts of flu per year, you have allergies or asthma, or you've been inconsistent or just getting back into training, subtract five from that number. If you've been training consistently for up to two years without any of these problems, just keep that number 180 minus age. Now if you've been training for more than two years without any of the problems listed above and you made progress in competitions without injury, you can add five. So you can take 180 minus age and add five. So once you've figured out what that heart rate is, 80% of your training or about 16 hours per week would be performed in that zone. Long easy aerobic with another four hours per week being allocated to hiit. So for example, if you're a triathlete, four hours of HIIT allows you enough time to perform one or two intense interval training sessions each week for the swim, the bike and the run. This might be two 30 minute swim workouts with short 25 to 200 meter repeats, 1.5 to 2 hour bike workout with 8 to 10 short steep hard hill climbs and a full recovery after each climb and one track interval based running workout with one hill based running workout. If you simply can't perform your hit sessions above your lactic acid threshold Then you you're probably doing your aerobic sessions too hard. Now this is all painting with a fairly broad brush. There's actually an entire branch of exercise training and science devoted to the concept of periodization which dictates splitting your buildup to an event or a race into periods of the year that have a specific training focus. In a traditional periodization model based on polarized training, you may end up training closer to say 90% aerobic, 10% HIIT during the off season and have 70% aerobic, 30% hit, as you say, build up to a race. Or from an even longer term periodization perspective, an athlete on a four year Olympics development plan may be skewed towards a higher percentage of aerobic training early in the process and as the years progress towards the Olympics gradually increase more and more race or competition intensity pace intervals. But this book is about how the average everyday athlete can train while tackling the delicate balance between health and performance. And part of that is keeping things relatively simple. And so if you were to simply step back and graph your approximate training percentage for the entire year, just make sure it comes close to that 8020 approach. Now if this whole polarized training thing sounds like a lot of potentially exhausting time spent exercising, you're right, it definitely is. So how on earth do professional endurance athletes pull off this type of approach for as many as 25 to 35 hours a week without being completely crushed by stress? Well, Mark Sisson gives an excellent perspective on this conundrum in his book the Primal Connection, in which he describes how a major factor at play and the success of the pro endurance athlete is the absence of significant work stress, deadlines, office obligations, et cetera in the life of someone who's able to devote most of their time to training. Here's how Mark puts it in a section of his book in which he describes describes his experience coaching a team of world ranked professional triathletes, comparing their lives to that of the amateur triathlete. The typical amateur triathlete was a type A overachiever with a demanding career and a busy family life. Fitting in the requisite workouts was a constant juggling act between work and family obligations. The word squeeze was used repeatedly to describe scheduling efforts starting with the morning alarm and an abrupt commencement of the day's first workout. Pacing seemed to be an obsession not just for tracking workout speed, but minding the clock at all times in order to remain on time for every item on the packed daily agenda. The popular quick lunchtime swim workout referred more to the peripherals than the lap times. Rushing out of the office, a presto change o in the locker room, a one minute post workout shower, and then bursting back into the office an hour later with water beads still dripping from the hair onto the collar. In contrast, professional athletes whose job was to simply race fast lived lives centered around their workouts with minimal interference from real life distractions or social obligations. While the pros conducted their workouts aggressively, the pace of their lives was leisurely. Lunchtime swim, sure. But instead of toweling off, jerking the tie back into place and rushing out to the parking lot, the post swim routine, the pros consisted of lingering in the poolside spa for nearly as long as the workout, shooting debris, stretching tight muscles, and generally decompressing from the intense effort in the water. Eventually, the pack moved from the spa into an easy lunch with more shooting of the breeze. Eventually they remounted their bikes for a couple more hours of pedaling, then took an afternoon nap followed by a late day run followed by a stretching or icing session, followed by a quiet evening of television, reading or lingering over a huge meal. As I spent more time in their world, I learned that the competitive advantage enjoyed by these professionals went beyond their impressive workouts. Embracing life both with purpose and at a more leisurely pace produces extraordinary results. So in a nutshell, stress is stress, no matter whether it's from exercise or from lifestyle. And the more stress you're placing on yourself from your lifestyle, the less stress you'll be able to place on yourself from exercise. And what if you don't have time to do polarized training? You don't want to waste your time with junk miles, but you also don't want to damage your body with excessive hiit. What I'm about to explain to you is exactly how I personally train for endurance and it's very similar to the method that I use with with most of my clients and athletes. I call it the ancestral athlete approach. And here's why. If you take a glance at our modern sedentary lifestyles combined with our post industrial diets, we've pushed ourselves far above and beyond what our bodies are conditioned to expect. Use your imagination for a moment to picture the typical post industrial day of sitting in an office surrounded by electromagnetic frequencies, deadlines, stress and fake food. Now contrast this death by sitting day with the more natural life our ancestors lived, which involved relatively high amounts of low intensity physical activity like hunting, gathering, farming or gardening. And these low intensity but hardly sedentary days were combined with sudden bursts of high energy like when it became necessary to run from a lion, move a heavy rock or log, or engage in hand to hand combat. And it was very rare to spend several hours a week simply training mindlessly at a threshold pace. That would just be a great way to deplete energy stores and beat up the body with no practical benefits. So think of it this way. Until the recent industrial era, life was a constant physical challenge. We didn't have refrigerators, preservatives, microwaves, fast food or pizza delivery to help us put dinner on the table. Rather than jetting to the grocery store with a credit card, we'd wander on the plains with a weapon or go out to gather grasses, grains, fruits and vegetables. And we'd expend extra energy properly preparing these natural foods. And while there were certainly drawbacks to this seemingly crude or uncomfortable mode of existence, the benefits for physical fitness and endurance building were potent. An ancestral approach to training is based around the theory that we're naturally designed to perform very high amounts of low level physical activity combined with an occasional very high intensity burst. And when it comes to this delicate trade off between health and performance, this allows for building endurance without inflicting significant physical and metabolic damage. Living and training in this ancestral manner means respecting our ancestors and thinking critically about how the environmental and training stresses we place in our bodies affect our health in a positive or negative way. You may want to check out AncestryFoundation.org or go over to BenGreenfieldFitness.com and listen to my interview with Art Devaney if you want to learn more about how the ancestral concept applies not only to training, but also life in general. Of course, I'm all about the in the trenches application of these philosophies. After all, you can dream about hunter gatherers all day long, but it doesn't help if you're still headed out the door every day at lunch to pound the pavement for an hour. So let's see what the ancestral athlete approach would look like using an Ironman triathlon training routine as an example. Now, a sample week of training should be based around one mid to long aerobic session per week for swimming, one for cycling and one for running. Now this session is actually devoted to a high amount of time spent in your aerobic zone two with a few focused zone three race pace intervals. For Ironman, this would mean for example, you might have a two to three hour focused interval training session on the bike, a 60 to 90 minute high quality run, and a 45 to 60 minute swim that incorporates longer 400 to 1000 meter intervals and that's it. Those are the only three long sessions per week. Now here's the important key to the ancestral athlete approach. The remainder of your aerobic training should be accomplished by just staying active throughout the day. Now you'll learn about many biohacks later in this book like treadmill workstations, cold thermogenesis, electrical stimulation, suspension trainers, etc. That you like to implement this concept more easily into your everyday life. But examples include standing and walking as much as possible. I stand six to eight hours per day while working, I often conduct phone calls and consults while walking, and I'm even recording this entire audiobook while standing and shuffling around a bit. Never sitting for longer than an hour at a time without standing and doing 50 to 100 jumping jacks or five doorway pull ups or 20 push ups or squats or some other kind of calisthenic movement. Spending as much time as possible outdoors in the fresh air sunshine, experiencing both hot and cold temperature fluctuations and avoiding carrying your phone, electronics and other electrical devices Lifting something heavy every day. I usually flip a tire a few times or load up a barbell in the garage. Commuting whenever possible, whether on a mountain bike or by foot, or even by learning new modes of movement like parkour, movenat or fitness exploring. Beginning every day with cold showers to spark the metabolism, followed by deep nasal breathing and stretching, learning how to breathe, standing and moving properly so that your aerobic metabolism stays elevated throughout the day. Now, once you've programmed your long aerobic sessions, that one swim, that one bike and that one run on the days that create the least lifestyle stress for you, which is typically the weekend for the average everyday athlete and the light physical activity I just got done describing is naturally worked into your life. You then just inject brief bouts of high quality intense workouts and structured weight training sessions throughout the week. But you only do them if you're completely rested and ready to do them with perfect form. So using these concepts, an Ironman triathlon training week might look like Monday 30 minutes of easy bicycling skills and drills, 20 minutes of easy swim drills. Tuesday 20 minutes of heavy barbell lifts with 30 minutes of running via an interval based HIIT workout. Wednesday 30 minutes of cycling via an interval based HIIT workout and 30 minutes of HIIT based swimming. Thursday 20 minutes of heavy barbell lifts with 30 minutes of easy run drills. Friday 60 minutes of injury prevention and core training yoga or an easy swim Saturday the long bike ride with 2.5 hours of 20 minutes on 5 minutes off cycling intervals at a race pace along with a 3 by 1000 meter swim at race pace and then Sunday the long run with 60 to 90 minutes of 9 minutes on 3 minutes off running intervals at race race pace. Now it's important to understand that this train less approach I just described will only work if your body is primed for optimal health, which you're also going to learn exactly how to accomplish in future chapters. You should also understand that what I just described to you involves 8 to 10 hours per week of training versus the typical 20 to 30 hours per week that a lot of Ironman triathletes use. And although that brief description of an ancestral athlete training week may seem like it merely scratches the surface, don't worry. In later chapters of this book I'll be teaching you every biohack, healthy living component, recovery protocol, nutrition blueprint and strategy. You need to ensure you're able to proceed in training and beyond training with zero guesswork. Now I want to include a special note at the end of this chapter. One concern repeatedly expressed to me by older athletes is the fear of tearing a muscle, getting a sprain or strain, or developing a stress fracture from the highest intensities experienced during a HIIT training session. It's true that it can certainly get a bit more difficult to jump, sprint and run and move just as powerfully as you may have been able to in your younger years, and there's a few reasons why. Number one, your metabolism decreases with age by about 10% from your 30s to your 60s and a further 10% from your 60s onwards. That means you gain fat more easily. Your maximum oxygen consumption decreases by significantly each decade from 25 to 65 years of age, and then decelerates even more quickly, which means intense cardiovascular efforts get very difficult. Next, you get less responsive to energy stimulating hormones called catecholamines like epinephrine, and as a result your maximum heart rate decreases, which can decrease the intensity of heart efforts. Next, the total amount of blood your heart pumps per beat and the ability of your muscles to extract oxygen from that blood decrease, which can affect your cardiovascular capacity. Your muscle strength peaks around 25 years old, plateaus through 35 or 40 years old, and then begins to decline quickly with 25% loss of peak strength by the time you're 65. This is due to a loss in the number of muscle fibers. Your tendon, ligament and joint elasticity is decreased as cross linkages form between soft tissue fibers in these areas. This causes a loss of 2 to 4 inches of lower back and hip flexibility. Your bone density decreases as the calcium content of your bones gets lower and the matrix inside the bone begins to deteriorate, which can lead to increased risk of osteoporosis or fractures, especially in women. But don't get depressed and let this information convince you that you shouldn't go near heavy weights or track instead. The HIIT approach for an aging athlete can have a dramatic anti aging effect on many of the variables that I just listed. For example, hard running intervals that involve heavy breathing and burning muscles can help to boost a slowing metabolism, slow the rate of VO2 max decline, improve venous return back to the heart and put your body through a greater flexibility enhancing mobility compared to a slow jog when performed in moderation. The impact from hard running also has a potent bone building effect for both bone density and staving off the loss of muscle that occurs with aging. Loading of the bones and joints along the long vertical axis is very effective and can be achieved with the strength exercises that I'll discuss later in the in this book. Like squats, overhead presses, chest presses or lunges, these same exercises can build new neurons and challenge your body and mind to move through movements that can be more complex than just riding a bike. A study done at the University of Trasos Montes explains that a high speed power based weight training program in older individuals can increase functional capacity of the upper and lower body extremity muscles much more efficiently compared to a program that only includes slow and controlled weight training. And both high intensity intervals and weight training cause a catecholamine and hormonal response that keeps your maximum heart rate elevated and maintains your body in a relatively anabolic state compared to pure low intensity cardio. In other words, by exposing your body to the hormone rush, mental stimulation and thrill of lifting heavy stuff or sprinting, you actually stay young. Or in the words of 83 year old Ironman world record holder Lou Hollander, go anaerobic every day. Well, there's a lot of chapter resources, helpful websites, scientific references and surprise bonuses for this chapter, including training plans. So if you want to get those now, go over to BeyondTrainingBook.com chapter three that's BeyondTrainingBook.com chapter three and grab those resources today. Enjoy.

You've been listening to the Ben Greenfield Fitness podcast. Go to BenGreenfieldFitness.com for even more cutting edge fitness and performance advice. Sam.