Dr. Tabatha Barber explains how your body's cortisol rhythm syncs with light exposure: low at night, rising in the morning. Morning sunlight triggers the cortisol awakening response, while dimming lights and avoiding screens in the evening help you sleep. Shift workers face extra challenges keeping these rhythms stable.
Questions this video answers
10–15 minutes after waking (up to 30 minutes max).
About 20 minutes in the morning during winter.
Go to sleep around 10:00–10:30 PM.
At least two hours before bed (or use blue-blocker glasses).
Dim lights for the last hour or two and engage in relaxing activities (read, massage, meditate).
Chapters
The sleep waking cycle, that's my next thing. Under regular circumstances, you have low cortisol levels in the evening. You saw how that pattern came down nicely for you to go to sleep. And then in the morning you wake up and it comes up. And what's regulating all of this are actual clocks in your body. They're hormone clocks. They're part of our circadian rhythms. We have them in our brains and they're responding to the external stimuli in the world. And it's telling our body when to make our hormones. So it really is imperative that you live by the sun and nature's rhythms if you want to stay in sync, because that's how our clocks are created to be. So shift workers, especially third shift workers, this is going to be your biggest hurdle to overcome, is the fact that you're living against your body's natural hormone clocks. I have yet to meet a shift worker who has balanced hormones and, you know, is functioning properly, unfortunately. So sometimes you have to make hard decisions and change jobs or set more boundaries or do biohacks like, I use a full spectrum white light. It's a little light. You can buy it on Amazon or anywhere. And I will literally shine that in my face for the first 20 minutes in the morning throughout the winter, because we don't get sun in Michigan and sun hitting your retinas in the morning is what stimulates your cortisol awakening response. It's what's talking to your hormone clock and saying, it's time to wake up, it's time to make the donuts, it's time to make the cortisol, right? So you need to get out in the sun the first 10 to 15 minutes after you wake up, half an hour max. And get out there. No sunglasses. Don't block the sun. Don't stare at the sun, obviously, but let it hit your retinas. And if there's no sun, you got to use the white lights. So shift workers, that's what I would recommend. You need to go to sleep around 10, 10:30. If you go to sleep at midnight, some, you know, one o', clock, your clock is going to miss the message to make melatonin. You're not going to make melatonin, therefore you're not going to get good sleep. You want to get to bed early enough and then you want to avoid electronics at least two hours before bed. Or use blue blocker glasses. That blue light suppresses your hormone clocks. It prevents them from knowing that it's nighttime. So the best thing you can do is to dim your lights for the last hour or two. Get chill. Read a book, massage your partner, you know, do some meditation. Do all of that chill stuff that tells your clocks, oh, it's evening time. We can unwind. We can decrease that cortisol production and get out of that sympathetic mode so that we can actually start to lose some weight.
