Why Your Sleep Schedule Matters As Much As Duration

In this episode we discuss:

• Why sleep-circadian disturbances are the rule—not the exception—in mental health
• The “wired and tired” pattern and what actually causes it
• Why sleep duration alone is an incomplete metric of sleep health
• The top drivers of sleep quality
• Why adolescents are biologically wired to stay up later and why early school start times are harmful
• Practical circadian interventions for adults and teens
• When and how supplements can support circadian alignment and nervous system regulation

Show notes:

• “Mendelian randomization evidence for the causal effect of mental well-being on healthy aging” by Ye, C.J., et al.
• “An update on adolescent sleep: New evidence informing the perfect storm model” by Crowley, S.J., et al.
• “Exploring the Role of Circadian Rhythms in Sleep and Recovery: A Review Article” by Desai, D., et al.
• “Efficacy and safety of ashwagandha (Withania somnifera) root extract in insomnia and anxiety: A double-blind, randomized, placebo-controlled study” by Langade, D., et al.
• “The sleep-circadian interface: A window into mental disorders” by Meyer, N., et al.
• “A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality” by Ngan, A., & Conduit, R.
• “High sensitivity and interindividual variability in the response of the human circadian system to evening light” by Phillips, A.J.K., et al
• “Pilot trial of Melissa officinalis L. leaf extract in the treatment of volunteers suffering from mild-to-moderate anxiety disorders and sleep disturbances” by Cases, J. et al.
• “An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study” by Lopresti, A.L., et al
• “Social jetlag: Misalignment of biological and social time” by Wittmann, M., et al.
• Learn more about the Adapt Naturals Core Plus bundle or take our quiz to see which products best suit your needs
• If you’d like to ask a question for Chris to answer in a future episode, submit it here
• Follow Chris on Twitter/X, Instagram, or Facebook

Hey everybody, Chris Kresser here. Welcome to another episode of Revolution Health Radio. Today we’re going to talk about sleep, but not in the way you’ve probably heard before. We’re not going to focus on how many hours you’re getting. Instead, I want to talk about something I think could be more important for most people, which is when you’re sleeping relative to your internal biological clock. This is the circadian piece of sleep that doesn’t get nearly enough attention in mainstream conversations about sleep health.

When I was in practice, I worked with a lot of people who were doing everything right according to conventional sleep advice. They were getting seven or eight hours in bed, sleeping in a dark room, avoiding screens an hour before bed, etc, and yet they often still felt exhausted in the morning. They dragged through the day needing caffeine just to function, and then at night, they’d hit the pillow feeling completely exhausted but somehow too wired to fall asleep. I used to call this pattern “wired and tired,” and it was probably the most common sleep complaint I saw in my practice. I also worked with a lot of night owls who told me they naturally had more energy at night and preferred going to bed at 1 or 2 am. The problem was they still had to wake up at 6:30 or 7 to get their kids to school or be at work by 8 or 9. So they were living in a constant state of sleep debt, not because they weren’t trying to sleep, but because their schedule didn’t match their biology.

In this episode, I’m going to walk you through some new research on sleep and circadian rhythms and mental health, explain what’s driving sleep quality beyond just duration, talk about why adolescents and teenagers are especially vulnerable to circadian disruption, and share practical interventions you can use to support your circadian biology and improve your sleep. Let’s dive in.

A major review came out in early 2024 in the Proceedings of the National Academy of Sciences, or PNAS. It was a comprehensive review by researchers from King’s College London, Stanford, and several other institutions looking at the relationship between sleep circadian rhythms, and mental health disorders. The title of the paper tells you a lot – “The Sleep Circadian Interface: A window into mental disorders.” What they found was really interesting. Sleep and circadian problems aren’t just associated with one or two mental health conditions. They show up across the board in depression, anxiety, bipolar disorder, psychosis, and more. The authors made an important statement that I want to highlight. They said that sleep-circadian disturbances are “the rule rather than the exception” in mental health conditions. Not the exception, the rule.

Over 85 percent of adults in community mental health treatment met criteria for two or more sleep-circadian problems at the same time. This tells us that how well your sleep timing lines up with your internal clock is foundational to mental and physical health. It’s not a side issue, it’s central. And yet, most of the public conversation about sleep is still only about duration. “Get your eight hours.” That’s the message we hear over and over. For a lot of people, eight hours is the right target, but there’s real individual variation here that doesn’t get discussed. Some people do great on seven hours. A smaller number do fine on six. I’m one of them. I typically sleep six and a half to seven hours and feel rested and recovered when I wake up. I’ve done a lot of experimentation here, and I’m pretty comfortable with this duration, and it tends to run in my family. And that’s what you’ll find as well – short sleepers, there’s a genetic trait that tends to confer that quality, and you often see it present in families.

The problem is that the eight hour message has become so dominant that people who hit that number but still feel terrible assume something’s wrong with them, and something is often wrong, but it’s not usually duration. It could be timing, or consistency, [or] circadian alignment. There’s no lab test right now to tell you whether you need six, seven, or eight hours. It comes down to experimentation and paying attention to how you feel. But we can say with confidence that the fixation on duration has overshadowed these other factors, and that’s a problem.

What Really Drives Sleep Quality

Based on my clinical experience and the research, I’d rank the factors driving sleep quality in this order. First and foremost is light exposure. This is number one, and it’s also a two-part equation. On the evening side, you need to reduce blue light exposure for at least an hour before bed. And I’d put this ahead of morning light in terms of priority. Blue light suppresses melatonin and tells your brain it’s still daytime. If you’re on your phone or iPad in bed, scrolling until you pass out, you’re sending the exact wrong signal to your circadian system. Your brain thinks it should be alert right when you need it to wind down. On the morning side, you want bright light exposure, ideally natural sunlight, within the first hour after waking. This is one of the most powerful signals you can give your circadian clock. It sets the timing for cortisol release, body temperature regulation, and melatonin release that night. Everything downstream depends on that morning signal. Now, of course, some people live at latitudes where it’s still dark in the morning, and in that case, a light machine that emits about 10,000 Lux can be really helpful. But if you can get outside and get exposure to natural light, the lumens from the sun and from natural light exposure absolutely dwarf what you can get from a light machine. And there are some other benefits, of course, to being outside. So that’s the preferred method, if possible.

The PNAS review noted about a 50-fold difference in how sensitive people are to light’s circadian effects. That’s a pretty big range. It depends on age, genetics, eye health, and recent light exposure history. Some people need very aggressive light management, while others are less sensitive. But almost everyone underestimates how much light matters for sleep and circadian health.

Second is sleep-wake consistency. This one is also underrated. Going to bed and waking up the same time every day, including weekends, goes a long way toward regulating your circadian biology. Your body craves rhythm and predictability. You probably heard the term “social jet lag.” That’s when your biological clock and your social schedule don’t match up. Classic example is staying up super late on Friday and Saturday and sleeping in, then dragging yourself out of bed Monday morning. That two or three hour shift from the weekend to the week creates a kind of chronic mini jet lag that accumulates over time. The research shows real consequences for mood, metabolism, and cognitive function.

Third is meal timing. This one gets overlooked, but eating an early dinner works a lot better for sleep than eating late. If you’re targeting a 9 pm bedtime, finishing dinner by 5 or 6 pm is ideal. Your gut has its own circadian rhythm, and eating late throws it off. It elevates blood sugar and insulin at a time when your body is trying to wind down and prepare for sleep. And then, finally, supplements can help, but they’re not the first move. They work best when the foundational behaviors are already in place. And I’ll come back to this in a little bit.

Most sleep advice focuses on getting enough hours—but many people still wake up exhausted. This episode dives into the overlooked role of circadian rhythms and explains why when you sleep can be more important than how long you sleep. #RHRpodcast #circadianalignment #ChrisKresser

The Adolescent Crisis

I want to spend some time talking about teenagers, because the research here is particularly concerning, and this is personal for me. I have a 14-year-old daughter, so I pay close attention to this topic. Adolescence is when risk for psychiatric disorder spikes, and it happens to coincide with major changes in sleep biology. Teenagers naturally shift toward later chronotype during puberty. Their internal clock pushes them to stay up later and wake up later. This isn’t laziness or bad habits, it’s biology. Their brains are wired to operate on a different schedule than younger children or adults. The problem is that social structures don’t accommodate this biological reality. Most high schools start at 7:30 or 8 am which means teenagers are waking up at what is, for their biology, the middle of the night. The result is chronic sleep deprivation, impaired mood, worse academic performance, and increased vulnerability to anxiety and depression. And it’s not just about feeling tired. The PNAS review found that late chronotype in adolescence is linked to higher rates of depression, anxiety, bipolar disorder, psychosis and even suicidality. Mendelian randomization studies suggest this isn’t just correlation, it’s likely causal.

In our household, we have substantial parental controls on our daughter’s phone. It turns off an hour before bedtime and stays off all night. She’s not allowed to bring it into her room at bedtime. It charges in a designated spot outside of her bedroom, and this removes temptation completely, even though, because it’s off during the night, there’s not much she can do with it anyways. We also got lucky with school start times. In her district, her high school starts at 8:45 am, because the district reviewed the research on sleep, circadian rhythms, and adolescent chronotype shifts, and made the smart decision to start later. Not every district has done this, but it’s something worth advocating for, if you have the opportunity. The evidence supporting later school start times for teenagers is strong, and many districts around the country have already moved in that direction. If you don’t have control over school start times, and of course most families don’t, it becomes even more important to protect bedtime. Set firm boundaries around technology use. Given what we know about adolescent brain development and the importance of sleep during this window, this deserves to be treated as a health priority, not just a convenience issue.

Practical Interventions and Supplement Support

Let’s talk about practical interventions. If you’re dealing with that wired and tired pattern, and  you want to improve your sleep quality, here’s where I would start. Again, light comes first. Get outside in the morning, ideally within the first hour of waking. Even 10 to 15 minutes of natural light exposure helps set your circadian rhythm for the day. In the evening, dim lights and avoid screens for at least an hour before bed. If you have to use devices in the evening, use blue light blocking glasses or enable the night mode settings on your device. Light exposure is the single biggest lever most people have for improving their sleep, and many are not using it effectively.

Consistency comes second. Pick a wake time and stick to it, even on the weekends. I know that’s hard for a lot of people, but your circadian system will thank you. The more regular your schedule, the easier it becomes for your body to anticipate sleep and wakefulness at the right times. And while there has been some controversy about this, it does seem that research is coalescing around the idea that earlier bedtimes and earlier wake times, so let’s say nine or 10 pm and waking up at let’s say 5 or 6 am in the morning, are generally better than a night owl type of schedule where you’re going to bed at 2 am and sleeping until 9 or 10 am. Even if you get the same total amount of sleep, there is some evidence that an earlier bedtime and an earlier rise time is beneficial.

Meal timing comes third. Finish dinner at least three hours before bed, if possible. If you’re targeting a 9 pm bedtime, that means eating by six. This gives your digestive system time to wind down, and prevents blood sugar and insulin spikes that can interfere with sleep onset. Now I don’t recommend being rigid about this. Life is full. There are lots of things, especially if you work and you have kids, there are lots of situations where this may not be possible. So don’t sweat it and don’t stress about it. Just make it a goal or an aspiration to shoot for on most days of the week.

Once these foundations are solid, supplements can add another layer of support. This is where Steady Spirit, the most recent product that we released at Adapt Naturals, comes in. I formulated it specifically for the patterns we’ve been talking about, the wired and tired syndrome, difficulty winding down at night, and circadian misalignment. It contains five standardized botanical extracts that work together to address these issues from multiple angles. Sensoril ashwagandha is a high potency ashwagandha extract with strong clinical data behind it. Multiple trials show it significantly reduces cortisol levels. That wired feeling at bedtime is usually elevated evening cortisol, and ashwagandha helps reset the HPA axis so your stress response can wind down when it’s supposed to. Studies show it can improve sleep quality by 72 percent compared to 29 percent in placebo groups, which is a really significant difference.

L-theanine is an amino acid found naturally in green tea. It promotes alpha brain waves, which is the state of calm alertness you experience during meditation or deep focus. It works fast, usually within 30 to 60 minutes, and doesn’t make you drowsy. It calms the nervous system without sedating you, which makes it great for that transition into sleep.

Lemon balm phytosome works through GABAergic pathways, which means it stimulates GABA and calms the nervous system. Studies show 87 percent of people taking it reported improved sleep quality compared to 30 percent on placebo. And importantly, it does this without the cognitive impairment you often get from pharmaceutical sedatives.

Affron saffron, which is a branded form of saffron, is particularly interesting because it’s been studied for both mood and sleep. What stands out is that, like L-theanine and lemon balm, it doesn’t sedate you. It improves sleep quality and next morning alertness, which suggests it’s working on circadian function, not just knocking you out chemically.

Holy basil rounds out the formula. It supports HPA axis function and helps stabilize blood sugar. This is important because stress and blood sugar are closely linked. Cortisol releases glucose, and hypoglycemia can trigger cortisol release. Holy basil breaks that cycle and provides broad spectrum adaptogenic support. I put these ingredients together because I wanted something that works on multiple dimensions of the problem. The L-theanine and lemon balm give you immediate calming effects within the first hour. The ashwagandha, saffron, and holy basil work over time on the deeper adaptogenic level, helping you to reset your HPA axis and restore normal cortisol rhythms. Together, they address cortisol dysregulation, nervous system hyperarousal, and circadian misalignment. Steady Spirit can be used with adolescents and teens as well, but I’d recommend working with a clinician on dosing for younger people to make sure it’s appropriate for their specific situation.

If you’ve been focused on sleep duration and it’s not working, it’s time to zoom out and look at the bigger picture. Your circadian system is a master clock that coordinates sleep, mood, metabolism, immune function, and cognitive performance. When that system is misaligned, you can sleep eight hours and still feel bad. The most powerful lever you have for influencing your circadian system is light exposure. Reduce it at night, especially blue light from screens, for at least an hour before bed. Increase it in the morning by getting outside within the first hour of waking. This single intervention can make a huge difference, and it’s something most people aren’t paying enough attention to. Start there. Get light exposure right, then layer in consistency with your sleep-wake schedule, earlier meal timing, and targeted supplementation as needed. If you’re a parent, take your teenager’s sleep seriously. The biological changes happening during adolescence are real, and the consequences of chronic sleep deprivation during this period can be significant. Set firm boundaries around technology use, advocate for later school start times if you have the opportunity with the local school board, and protect that bedtime window as a health priority.

Thanks for listening. You can find show notes and references for this episode at ChrisKresser.com and I’ll talk to you next time.