58: Sleep and Insulin Resistance with Dr. Ben Bikman

Just remember, everyone, insulin controls the fuel the body uses, what type of fuel it uses, how much it's using it, whether it wants to store some of the energy or nutrients or burn them and how they're burned. So insulin has its hand very firmly on the levers of nutrient metabolism and more in the body. And so it's always a matter of. It ought to be a matter of thought or a matter of wonder, what are the inputs that are controlling how insulin is then controlling human metabolism? And one of the very strong inputs, much of what we always focus on justifiably, will be the food we eat. That is a topic we will always come back to because it is the elephant in the room. It is the main driver of insulin. Now, there are other inputs that matter, and I think it's important for everyone attending, everyone zooming in or watching to appreciate one of the main ones is stress. I'll always say that stress is one of the key pillars of causing insulin resistance. Now, let's go one level deeper. What is one of the main foundations that this pillar of stress is built on? And sleep deprivation is a big one. It's a big one because of its impact on insulin resistance, which we'll look at highlighting a couple manuscripts in particular. But it's also a big one because it's just so darn prevalent these days where so many people are sleep deprived due to, well, just poor sleep hygiene. And I would say even poor sleep hygiene has a lot to do with food and not to. I promise I'll get to the manuscripts in a moment. I just feel compelled to mention this. I have found that the single most relevant variable that will predict or determine whether I have a good night of sleep or not will be whether I go to bed stuffed with food very, very full, or whether I go to bed a little lean. You know, I ate a modest dinner and I didn't snack into the evening. If I go to bed with a full stomach, my sleep is going to be terrible. As opposed to going to bed relatively leaner or not too comfortably full, but not stuffed. That'll make all the difference. Now, what happens then? So this particular study that we'll include in the notes, so it's called Sleep Restriction for One Week, Reduces insulin sensitivity in healthy men. Yes. That is an unfortunate aspect of many studies where they just included males in this. There are other studies that mixed and had men and women in it. This one was just really easy and lucid to get through. So I picked it just for the sake of convenience in highlighting the relevance so what they did was take these healthy individuals, these healthy subjects, and they tested their insulin sensitivity and a handful of other markers over several days when they were in bed for 10 hours. Now that of course that doesn't mean they were sleeping straight for 10 hours, but they had that ample window of sleep. And so that was considered a baseline. And so they measured their insulin sensitivity. They also measured relevant to stress. And this is why I put sleep deprivation in that category of stress. They measured the stress hormones and the prototypical, the poster child stress hormones are epinephrine and cortisol. Those are the key stress hormones that really underlies every stress response. If someone's experiencing emotional stress or physical stress like an illness, or even they're exercising too much, these stress hormones, cortisol and epinephrine will start to increase. Now they're doing all kinds of things throughout the body, but one of the main effects that they have, especially with cortisol is to push up glucose. It's that fight or flight mechanism. You know, historically, ancestrally the body, these hormones would be helping mobilize glucose and flush the blood with energy, fatty acids and glucose in order to fuel us getting away from whatever the danger was or addressing the danger head on. That is a process that gets somewhat hijacked when it comes to sleep deprivation. So they had them sleep well, they got a baseline, what's their insulin sensitivity, what are their stress hormones, specifically epinephrine and cortisol. And then they had them do a few days of restricted sleep down to five hours per night. Now many people listening may think, well, well that's what I get all the time. I'm always getting five hours of sleep. In fact, I'm very sensitive to that because I typically go to bed around 10 and I am often wide awake at 3, almost 5 hours on the dot. And then it takes me some time to fall back asleep. So I look at this manuscript and see some of my self reflected and what they did as the intervention regardless, five hours, they restricted them to five hour windows of sleep for several days and then they did, but not indefinitely, it was just a handful of days. And then they did a measure of insulin sensitivity again and a measure of these hormones again. Now let's look at the hormones first in table one and I'll hold it up here. So some people that are curious about statistics, they'll appreciate this when they looked at the cortisol number. Here's the cortisol and here is the epinephrine. In fact norepinephrine as well, those are the two catecholamines. They found P values. And in other words, the differences were less than 0.001 and in some instances less than 0.0001, including cortisol. And so there was a hugely significant increase in cortisol and epinephrine. And remember, especially cortisol. Cortisol is determined, it is called a glucocorticoid. Its main action is considered to be a pushing up of glucose. And so now of course you have this war between insulin and cortisol. Cortisol is pushing the glucose up, insulin is trying to push it down. And so we get into this sort of vicious cycle. As long as cortisol keeps pushing, insulin has to work harder and harder, increasing or reducing its efficacy. And that's what we see. I won't hold it up again. That's just too awkward. So in figure three, that's where they really detailed like an hour by hour change, in fact, 30 minute by 30 minute change in the cortisol levels. And from the very beginning of doing this new test, after a few days of five hours a night, the cortisol was immediately higher and at some time points it was twice as high than the people who were in the same person compared to when they were getting a full night of sleep. And then in this study they did something called a continuous or a euglycemic hyperinsulinemic clamp. That is the gold standard, that is considered the best way of measuring insulin sensitivity. And they found that insulin sensitivity was significantly compromised in these people. So that's the study. Just a few days of sleep restriction down to five hours per night resulted in significant elevation of stress hormones and a significant, significant reduction in insulin sensitivity. Now, one other study that we'll provide the link to in the show notes was interesting because it looked at it in a different perspective, which I'll elaborate. Now, hormones, all hormones have some degree of a circadian rhythm. They're supposed to, they ebb and flow throughout a 24 hour period. Sometimes they ebb and flow in a more macro level, you know, in a longer period than just 24 hours. But cortisol follows a pretty typical 24 when people were sleep deprived. And it needs to, hormones need to go up and down. Insulin's also, it's no exception to this. They're supposed to come and go up, ebb and flow in order to function properly. What they found in the sleep deprived patients was it had compressed the variation. There was no longer this cortisol up and down in this kind of this big flowing pattern, it compressed it. And so rather than going like this, it went like this, but it was constantly elevated, it was much, much higher than it was before. So we were comp it and pushing it up. Over the course of a 24 hour period with sleep deprivation really reflective of what's becoming sort of a constant, a continuous elevation in cortisol. And once again that's making insulin work all that much harder. But cortisol has even more effects, not that I'll get into that now necessarily, but it results in the destruction of collagen in the skin. It can break down muscle, it can break down bone. In fact, all of this is to get those proteins, to break them down into amino acids to give them to the liver so the liver can make more glucose. So cortisol will wreck the body just to produce more glucose, of course, all the time creating more and more insulin resistance. Now, one last comment. Often when someone is sleep deprived, they will then try to make up for that by taking caffeine, which I get. Caffeine is a stimulant. In fact, it's the most widely consumed addictive drug in the world due to habits, in fact, probably more now than ever before because of our sleep deprivation. While that will help you feel more alert, it also will in fact potentially increase cortisol even more, which is when it comes to perhaps the sleep deprivation induced effects on insulin resistance, the caffeine may in fact compound the problem. I'm not telling people, I would just say this. Don't continue to rely. If you've been relying on caffeine to make up for your poor sleep deprivation, don't, don't focus on the caffeine as a solution. The solution needs to be better sleep habits, dimming the lights, and I would say very especially don't snack into the evenings. So again, don't rely on caffeine to continue to fix what is truly a sleep hygiene problem. Fix the sleep, you know, maybe, hopefully temper that caffeine down a little bit, all in an effort to help cortisol come down and then metabolic health improves.