Episode 23: How to Sleep Better — The Science and Daily Playbook

Sleep isn’t a luxury; it’s the foundation of every system in your body.
In this episode of The Dr. Kumar Discovery Podcast, Dr. Ravi Kumar explores the neuroscience, hormones, and daily habits that drive great sleep. You’ll learn how to optimize circadian rhythm, manage sleep pressure, and use evidence-based strategies to restore energy, focus, and long-term health.

Episode Highlights

The Architecture of Sleep — what happens during light, deep, and REM sleep
Two Forces of Sleep — how circadian rhythm and adenosine work together
Sleep and Health — how poor sleep drives insulin resistance, inflammation, and hormone imbalance
The Science of Light — how morning and evening light shape your sleep clock
Temperature Matters — why a cool room and warm extremities promote deep sleep
Consistency Counts — how regular sleep timing prevents “social jet lag”
Supplements That Work — magnesium, glycine, L-theanine, and tryptophan explained
Melatonin Myths — when it helps, when it doesn’t
Mind Before Bed — how mental wind-down reduces insomnia
The Hidden Factor — what to know about sleep apnea and when to get evaluated

Show Notes

The Science of Sleep

Sleep is an active biological process that repairs tissue, consolidates memory, balances hormones, and clears waste from the brain. Deep sleep triggers growth hormone release, resets cortisol, and restores metabolism. REM sleep connects emotion and memory, acting as nightly therapy for the mind.

How Sleep Works

Your body’s sleep rhythm runs on two systems. The first is circadian rhythm, the 24-hour clock synchronized by light entering the eyes each morning. The second is sleep pressure, driven by adenosine buildup during wakefulness. When these align—high sleep pressure meeting an open circadian gate—you fall asleep easily and naturally.

How Much Sleep Do You Need?

Adults need seven to nine hours per night. Anything less consistently impairs focus, mood, metabolism, and cardiovascular health. Children and teens need even more, as their brains are still developing. Regular sleep schedules strengthen circadian rhythms and improve restorative sleep quality.

The Foundation: Light, Temperature, and Timing

Morning sunlight within the first hour after waking anchors your circadian rhythm and boosts morning cortisol. In the evening, dim warm light preserves melatonin.
Keep your bedroom cool, around 68°F, and allow your body to release heat through hands and feet. Consistent bedtimes and wake times train every clock in your body—from your brain to your liver.

Supplements That Support Sleep

Tier 1: Start with magnesium (250–300 mg of elemental magnesium, ideally as glycinate) and glycine (3 g before bed).

Tier 2: If needed, add L-tryptophan or L-theanine for deeper relaxation.

Tier 3: Options like ashwagandha, saffron, or tart cherry extract may help, but try one at a time.

Melatonin: is best reserved for circadian rhythm shifts like jet lag or night shifts.

When to Screen for Sleep Apnea

If you snore loudly, wake up gasping, or experience daytime fatigue, you may have sleep apnea. Take the STOP-BANG questionnaire here: http://www.stopbang.ca/osa/screening.php
If your score is high, talk to your doctor about a formal sleep study. Treating sleep apnea can dramatically improve energy, blood pressure, and long-term health.

Transcript

[00:00 –> 00:16] On this episode of the Doctor. Kumar discovery. Sleep might be the riskiest thing any animal can do. When you’re asleep, you’re unconscious, unaware, and completely vulnerable to danger. And yet, every species ever studied still sleeps.

[00:16 –> 00:35] That alone should tell you how essential it is. I wasn’t just tired, I was completely broken. There wasn’t a single disease to treat. It was the cumulative cost of chronic sleep deprivation and relentless stress. So sleep literally fine tunes nearly every system from your blood vessels to your metabolism to your mind.

[00:35 –> 00:59] When we lose it, everything begins to unravel. The good news is that sleep is one of the most reversible risk factors in medicine. When you restore it, blood pressure drops, metabolism stabilizes, memory sharpens, and emotional resilience returns. When it comes to getting truly restorative sleep, the first lever you need to pull is My name is Doctor. Ravi Kumar.

[00:59 –> 01:27] I’m a neurosurgeon in search of the causes of human illness and the solutions that help us heal and thrive. I want you to join me on a journey of discovery as I turn over every stone in search of the roots of disease and the mysteries of our resilience. The human body is a mysterious and miraculous machine with an amazing ability to self heal. Let us question everything and discover our true potentials. Welcome to the Doctor.

[01:27 –> 01:39] Kumar discovery. Welcome to the Doctor. Kumar discovery podcast. My name is doctor Ravi Kumar. I’m a board certified neurosurgeon and assistant professor at UNC.

[01:39 –> 02:05] Today, we’re talking about sleep. Sleep is something every human does, yet most of us don’t respect how vital it truly is. We spend nearly a third of our lives asleep, but in our productivity obsessed culture, sleep is treated like a luxury, not a biological necessity. To understand how important sleep is, think about this for a moment. Sleep might be the riskiest thing any animal can do.

[02:05 –> 02:28] When you’re asleep, you’re unconscious, unaware, and completely vulnerable to danger. And yet, every species ever studied still sleeps. That alone should tell you how essential it is. Before I was a neurosurgeon, I was actually a marine biologist. One of the things that stuck with me while studying marine mammals and seabirds was how they balance their need for sleep with the demands of their environment.

[02:29 –> 02:55] Marine mammals like dolphins live in the water, but breathe air just like us. They have to come up out of the water to breathe, but they can’t skip sleep. So they rest one hemisphere of their brain at a time. One side sleeps while the other stays awake, guiding them to the surface for air and scanning for danger. Birds do the same thing in mid flight across oceans and continents, literally sleeping with one eye open as they glide through the air.

[02:55 –> 03:17] That’s how deep the biological drive for sleep runs. When animals are completely deprived of sleep, they die within about eleven days in controlled experiments. And throughout history, sleep deprivation has been used as a form of torture. That’s how destructive the lack of sleep can be. So yes, sleep is essential for survival, but it’s also one of the easiest levers we can pull for optimizing health.

[03:17 –> 03:41] We talk endlessly about nutrition, exercise, supplements, and meditation. All those matter, but none can compensate for poor sleep. Sleep is the foundation that everything else sits on. It regulates your hormones, repairs your brain, resets your metabolism, consolidates memories, and stabilizes your emotional balance. If you fix your sleep, you amplify the benefits of everything else you do.

[03:41 –> 04:08] So if you’re chasing biohacks, supplements, or new diet trends but haven’t dialed in your sleep, stop. Get your sleep right first because if you don’t, everything else you build will be on sand. In this episode, we’ll explore the science of sleep. By the end, you’ll understand what sleep truly is, what happens when we don’t get enough, and how to use it as one of the most powerful tools for health and longevity. So before we go any further, I wanna give you a quick disclaimer.

[04:08 –> 04:29] I’m a medical doctor, but I’m not your doctor. This show is for informational purposes only. It’s not meant to diagnose or treat any medical condition. The goal of this podcast is to give you knowledge because knowledge is power, and with power, you can take action to improve your health. It’s important to note as well that this podcast is separate from my role as assistant professor at UNC.

[04:29 –> 04:47] And also one more thing, I’m really trying to grow this podcast so I can reach more people. To do that, I need reviews on Apple Podcasts and Spotify Podcasts. If you’re willing, please do me a favor and leave a written review there. That’s the one thing I’ll ever ask of you, and if you’re willing to do it, I will be so appreciative. Okay.

[04:47 –> 05:13] So let’s start our investigation of sleep with a personal story. As you know, I’m a neurosurgeon, and to become one, I had to go through seven years of neurosurgical training. Anyone who’s been through surgical training knows it’s brutal, but neurosurgery takes that and multiplies it by two or three. For some reason, my specialty glorifies toughness, long hours, no sleep, full adrenaline. In neurosurgery, exhaustion is worn like a badge of honor.

[05:13 –> 05:31] During residency, I routinely worked eighty to a hundred hours per week, sometimes more. That’s not an exaggeration. I’d come home, collapse on the floor, and fall asleep mid sentence reading to my children. Then I’d wake up before 5AM the next morning and do it again. And the crazy thing is, I thought it was fine.

[05:31 –> 05:44] I thought that was what it took to become something great. But honestly, it took a toll. Two of my children were born during residency, and I barely got to see them grow up. My marriage felt like a long distance relationship. My wife was essentially a single mother.

[05:44 –> 06:03] I kept telling myself it was temporary, that we’d get through it and then move on to the good life. But when those seven years ended and the adrenaline stopped, my body fell apart. My thyroid shut down, my testosterone plummeted, my energy disappeared. I wasn’t just tired, I was completely broken. There wasn’t a single disease to treat.

[06:03 –> 06:26] It was the cumulative cost of chronic sleep deprivation and relentless stress. I had spent every biological dollar I had, and when the debt came due, I had nothing left to give. It took me more than seven years to rebuild my health, and that experience completely changed the way I think about sleep. It’s not optional, and it’s not weakness to need it. It’s the foundation of all human health, wellness, and performance.

[06:26 –> 06:54] You can skip a few meals, you can miss a few workouts, but skip sleep long enough, and your body will collect the bill. What’s crazy is that the world still glorifies sleeplessness. Harvey Cushing, one of the fathers of neurosurgery, worked around the clock, chain smoked, and died of a heart attack. Thomas Edison bragged about sleeping four hours a night, and Margaret Thatcher did the same. But imagine what they could have been if they had respected sleep, possibly sharper, calmer, more creative human beings.

[06:54 –> 07:12] Who knows? We’ve made the mistake of treating sleep like the enemy of ambition, but sleep is not the enemy. It’s the fuel. It’s the force that powers ambition, performance, and longevity. The critics of sleep throughout history assumed it was a passive state, a time when nothing was happening, a time when productivity was lost.

[07:12 –> 07:38] But that couldn’t be further from the truth. Sleep is an active process. It’s when the body repairs itself, recalibrates hormones, clears toxins, and restores energy. Every night, your brain literally washes itself out, flushing out metabolic waste like beta amyloid, the same molecule that accumulates in Alzheimer’s disease. When you deprive yourself of that process, you’re not just tired, you’re functioning inside a neurologically toxic system.

[07:39 –> 08:01] So the next question becomes, how did we actually begin to understand the importance of sleep? Where did our understanding that we currently have today start? For centuries, people knew intuitively that sleep mattered. Communities organized themselves around that need with different people staying awake at different times. It was kind of a sleep relay race that we call chronotypes now, which ensures that everyone could safely rest.

[08:02 –> 08:31] But it wasn’t until scientists began systematically studying what happens when we’re deprived of sleep that we started to grasp how essential it truly is. In the late eighteen hundreds, two psychologists, doctor Patrick and doctor Gilbert at the University of Iowa, ran the first controlled human sleep deprivation experiments. They took healthy adults and kept them awake for ninety straight hours. What they found was fascinating. As the hours passed, reaction time slowed, motor coordination declined, and memory collapsed.

[08:31 –> 08:54] By about seventy two hours without sleep, participants could barely focus. Yet when they finally allowed them to sleep, recovery was almost complete after just a couple long rest periods. It was a simple, bold experiment, but it marked a turning point in human understanding. That work by Patrick and Gilbert in Iowa was the birth of sleep science and ultimately the field of sleep medicine. Medicine.

[08:54 –> 09:27] Everything that came later, our understanding of REM cycles, circadian rhythms, the links between sleep, metabolism, and cognition, all of it traces back to those early experiments by these two pioneering researchers. So I think the next thing we should talk about before we go further into why sleep matters is to understand what it actually is. Because sleep isn’t just shutting off. It’s a carefully orchestrated biological rhythm, a sequence of distinct stages that serve different purposes. Your brain cycles through these stages about every ninety minutes, completing roughly four to six full cycles every night.

[09:27 –> 09:54] Each cycle moves through three stages of non REM sleep called n one, n two, and n three, followed by a stage called REM sleep, which stands for rapid eye movement. REM is when you dream. It’s also when the eyes dart back and forth beneath the eyelids and your body is paralyzed. All these stages are measured by something called EEG or electroencephalogram, which is a way of measuring brain waves during sleep. Let’s go through each stage briefly so you have a clear picture of what’s happening while you sleep.

[09:54 –> 10:21] Stage n one is the twilight zone between wakefulness and sleep. Your muscles relax, your eye movements slow, and your brain waves shift from alpha, the rhythm of quiet wakefulness, to theta, the rhythm of light sleep. It’s easy to wake from this stage, but it marks the point where the gates to the conscious world begin to close. The brain starts disengaging from external stimuli so you can dive deeper into restorative sleep. Stage n two makes up about half of your night.

[10:21 –> 10:46] This is where your brain stabilizes, consolidates memories, and begins serious housekeeping. On EEG, two electrical patterns stand out, sleep spindles and k complexes. Sleep spindles are rapid bursts of activity around 12 to 15 hertz. They act like noise filters, protecting sleep from interruption, but they also play a second role. They transfer memories from short term storage to long term storage.

[10:46 –> 11:08] Think of them like little data transfer waves, moving the day’s experiences into your mental hard drive. Stage n three is deep or slow wave sleep, sometimes called delta sleep. This is the heavyweight stage of restoration. On EEG, it’s dominated by slow, high amplitude delta waves. This is the hardest stage to wake from, and yet the brain is remarkably active.

[11:08 –> 11:36] It’s repairing tissue, building immune strength, pruning weak synapses, and reinforcing strong ones. This is also where metabolic recovery happens, where your brain begins its nightly detox, flushing out waste products through the glymphatic system. We’ll talk more about that later. And finally, we reach REM sleep, which is rapid eye movement sleep. If you’ve ever watched someone in REM sleep, their eyes flutter under closed lids even though the rest of their body is completely still.

[11:36 –> 12:02] That’s because almost every major muscle in the body is paralyzed in a state of atonia. The mind is dreaming, but the body is restrained, so those dreams aren’t acted out. On EEG, the brain looks almost awake with distinctive sawtooth pattern waves. During REM sleep, your brain weaves together emotion, memory, and creativity. It’s the time when emotional experiences are replayed and refiled without a surge of stress hormones.

[12:02 –> 12:29] That’s why REM sleep helps regulate mood, solve problems, and link abstract ideas. If you’ve ever had an amazing idea that came to you in a dream, it likely came to you during REM sleep. When you look at all these stages together, the architecture of sleep is beautifully layered. It’s a symphony of biological processes, each with its own rhythm and purpose, all working together to repair, regulate, and prepare you for another day of being human. Okay.

[12:29 –> 12:56] So now that we’ve talked about what sleep is, let’s talk about what causes us to sleep, how the body knows when it’s time to just lay down and fall asleep. We don’t fall asleep just because we’re tired. We actually fall asleep when two internal forces align. One is your circadian rhythm, the roughly twenty four hour clock that tells your body when to be alert and when to rest. The other is homeostatic sleep pressure, the biological drive that builds the longer you stay awake.

[12:56 –> 13:29] Together, these two systems, known as process c for circadian rhythm and process s for sleep pressure, choreograph every night’s sleep. When it happens, how it unfolds, and when it ends. Let’s start with process c, the circadian rhythm. Master clock that runs this rhythm lives deep in the brain, inside the hypothalamus, in a tiny cluster of cells called the suprachiasmatic nucleus or SCN. We know it’s the body’s timekeeper because when scientists transplanted the SCN from a healthy animal into another whose sleep wake cycle was broken, the rhythm was restored.

[13:29 –> 13:56] They literally transferred a running clock from one brain to another. In humans, this internal clock runs on a cycle of about twenty four point one eight hours, just a little longer than the Earth’s day. And each morning, it gets reset by light entering the eyes. Inside the retina are specialized retinal ganglion cells that contain a pigment called melanopsin. When morning light hits them, they send a signal through the retinal hypothalamic tract directly to the SCN.

[13:56 –> 14:21] The SCN then resets the body’s internal clocks and synchronizes systems throughout the body. It’s like a town square where everyone checks their watches against the clock tower. Each organ has its own rhythm, the liver, the gut, the heart, but the SCN keeps them all on time. One of the organs it talks to is the pineal gland, a small structure near the center of the brain that releases melatonin. Melatonin is your body’s darkness signal.

[14:21 –> 14:49] As light dims in the evening, melatonin rises, something we call dim light melatonin onset. It’s one of the most reliable markers that the biological night has begun. Then in the morning, when light hits the eyes again, the SCN triggers a surge of cortisol about thirty to forty five minutes after waking called the cortisol awakening response. This rise helps energize you, raise alertness, and set the tone for the day. Now let’s talk about process s, the homeostatic sleep drive.

[14:49 –> 15:14] This is your sleep pressure, the biological urge you feel that builds up the longer you’re awake and then releases during sleep. It’s tracked chemically by a molecule called adenosine. Adenosine builds up as you burn through energy because it’s the base molecule for your main energy currency, ATP. As ATP is used, adenosine accumulates. When it builds up in the basal forebrain, it binds to receptors that tell neurons to start quieting down.

[15:14 –> 15:31] That’s what gives you the heavy eyed, foggy feeling. It’s your body’s way of pressuring you into sleep. That’s why we call it sleep pressure. When you finally sleep, adenosine levels fall, releasing that pressure. So now that we understand process c and process s, how do these two systems interlock?

[15:31 –> 15:52] Think of sleep pressure, process s, as a rising tide that builds throughout the day. And think of the circadian rhythm, process c, as a gate that opens and closes. During the day, that gate stays shut, holding the tide back. But as evening approaches, the circadian gate opens. The tide of adenosine driven sleep pressure floods in, and you fall asleep.

[15:52 –> 16:18] If that gate opens at the wrong time as it does in circadian rhythm disorders, you feel completely exhausted yet unable to fall asleep. But when those two forces align, high sleep pressure meeting an open circadian gate, that’s when the body surrenders naturally to sleep. Okay. So now we know what sleep is, we know how it’s structured, and we understand the processes that control its rhythm. Now the question is, how much sleep do we actually need?

[16:18 –> 16:33] Many adults think they can get by on five or six hours a night, but the science is not ambiguous on this one. For the majority of us, that’s simply not enough. And it’s important to understand that sleep need isn’t about toughness. It’s about biology. There aren’t tougher people who need less sleep.

[16:34 –> 16:54] There are just people who defy sleep and operate below their potential. For most adults, the sweet spot is between seven and nine hours per night. That’s the consensus from the American Academy of Sleep Medicine and the Sleep Research Society. Seven hours is the minimum for good health. A bit more can be fine for some people, but too much can also be counterproductive.

[16:54 –> 17:18] Anything less than seven hours produces measurable declines in mood, performance, immune function, and metabolic health. For older adults, those 65, the goals shift slightly. Seven to eight hours is usually optimal. But with age, sleep becomes lighter and more fragmented with a less deep slow wave activity. For this group, the biggest predictor of restorative rest isn’t total hours, it’s actually regularity.

[17:18 –> 17:37] Going to bed and waking up at consistent times anchors the circadian rhythm and enhances restorative sleep. Now for children, it’s a completely different story. Their brains are growing, pruning, wiring, and learning, all of which requires more sleep. Here’s what the numbers look like for children. Newborns need fourteen to seventeen hours.

[17:37 –> 17:56] Infants need twelve to sixteen hours. Toddlers need around eleven to fourteen hours. Preschoolers, ten to thirteen hours, and school age children, nine to twelve hours. Short or irregular sleep in childhood consistently predicts worse attention, learning, and behavior across multiple studies. It also predicts higher metabolic risk.

[17:56 –> 18:18] Kids who sleep less are about twice as likely to become overweight later in life compared to those who sleep longer. Now for teenagers, the need is about eight to ten hours per night. But here’s what’s different about teens. Their internal clocks naturally run later during puberty. The circadian rhythm shifts by about one to two hours, meaning teens literally fall asleep later and wake up later.

[18:19 –> 18:44] Yet, we still require them to wake up for early school start times, which truncates their REM sleep and crushes their ability to emotionally regulate. That’s why delayed school start times have been shown to improve grades, mood, attendance, and even reduce car crash rates. So when your teenager stays up late, that’s not rebellion. That’s biology. And they often need the flexibility to sleep later in the morning to meet their physiological needs.

[18:44 –> 19:08] Now I know a bunch of parents of teens, including my brother and sister-in-law, are thinking, OMG right now, because the current lack of understanding in the school systems doesn’t match with the biological needs of our children, and it causes great grief for our kids and us as parents. Okay. So that’s sleep times, how much you need based on your age. Now we need to ask another question. How are we doing with sleep as a society?

[19:08 –> 19:35] And the truth is, not well. Chronic sleep deprivation has become a modern epidemic. According to the CDC, one in three adults in The United States doesn’t get enough sleep, and that deficit ripples across every system in the body, cardiovascular, metabolic, hormonal, and cognitive. To understand this better, let’s walk through how sleep deprivation breaks us down one system at a time. The cardiovascular system is one of the first to show impact.

[19:35 –> 20:10] Even a single night of short or fragmented sleep pushes the body toward higher blood pressure, inflammation, and sympathetic overdrive. That’s your fight or flight mode. Across large cohort studies, short sleep consistently predicts hypertension and heart disease. A meta analysis of 15 prospective studies involving nearly half a million people found that sleeping less than six hours per night was linked to a forty eight percent higher risk of coronary heart disease and a fifteen percent higher risk of stroke compared with getting seven to eight hours. Poor sleep also fuels inflammation, which is the root cause of vascular disease.

[20:10 –> 20:38] Even modest restriction just six hours a night for a week elevates c reactive protein and other inflammatory markers, priming the arteries for atherosclerosis. The next system to fall apart with sleep deprivation is metabolism. Even one night of poor sleep can push the body towards insulin resistance. That’s when your cells stop responding normally to insulin, so glucose builds up in the blood, essentially a prediabetic state. You feel it as sugar cravings, brain fog, afternoon fatigue.

[20:39 –> 21:09] Your body can’t get glucose into its cells, so it craves more fuel. In a landmark 1999 Lancet study, healthy adults restricted to four hours per night for six nights developed impaired glucose tolerance, higher evening cortisol, and sympathetic overdrive. Their bodies look metabolically older and stressed. Even one night of four hours of sleep can drop insulin sensitivity by 25% by the next morning. And then there’s the brain, which might be the organ that suffers the most when sleep is deprived.

[21:09 –> 21:37] Remember, sleep isn’t a passive state. It’s an active process of repair and detoxification. Your brain’s system to clear waste is called the glymphatic system. During deep sleep, the spaces between the brain cells expand by 60%, allowing cerebral spinal fluid to flow through and flush out toxins. Those rhythmic brain waves of slow wave sleep act like a biological pump, moving fluid through your brain tissue and washing away waste.

[21:37 –> 22:02] Among the waste products is beta amyloid, a sticky protein fragment that builds up in Alzheimer’s disease. Think of beta amyloid like the paper hole punches that fall into your sink. If you churn on the water and wash them down every night, they never accumulate. But if you never churn on the water, if you never sleep deeply, those hole punches pile up and clog the drains. That’s what happens to the brain when it’s deprived of sleep.

[22:02 –> 22:39] When beta amyloid accumulates, it creates oxidative stress and inflammation, which then causes another protein, tau, to clump inside the neurons. Both beta amyloid plaques and tau neurofibrillary tangles are hallmarks of Alzheimer’s disease, and they’re both washed out with deep sleep. And we can objectively see this happening in real time. PET scans show that after one night awake, healthy adults have higher beta amyloid levels in memory critical regions like the hippocampus. Even the morning drop in beta amyloid in spinal fluid disappears when people are sleep deprived, and long term studies confirm the connection.

[22:39 –> 23:11] In the Whitehall two study from London, people who slept six hours or less in midlife had a twenty two to thirty seven percent higher risk of dementia later in life compared to those who were getting seven or more hours. Those who consistently deprive themselves of sleep through their fifties, sixties, and seventies had a thirty percent higher risk of Alzheimer’s. Sleep is how your brain performs maintenance on itself. When you short change it, you’re not just tired, you’re letting neurotoxins accumulate. You should think of each night of deep sleep as an investment in your cognitive longevity.

[23:12 –> 23:33] Sleep is also your nightly endocrine reset. During deep sleep, growth hormone surges, cortisol drops, and testosterone pulses rise. When you cut sleep, you disrupt it all. About 60 to 70 of daily growth hormone release happens in the first few hours of deep sleep. That pulse drives tissue repair, fat metabolism, and muscle recovery.

[23:34 –> 24:04] Restricting sleep blunts that surge and keeps cortisol elevated at night, which is a double hit that promotes stress, insulin resistance, and slower recovery. Normally, cortisol peaks in the morning and falls at night as melatonin rises. But with sleep deprivation, that curve flattens. Evening cortisol can rise by 35 to 45% the next day after being sleep deprived, keeping you stuck in a stressed state when your body should be resting. And it doesn’t take long for testosterone to drop either.

[24:04 –> 24:36] In one JAMA study, healthy men restricted to five hours a night for just one week saw testosterone fall by 10 to 15%, which is roughly the decline expected from ten to fifteen years of aging. Sleep deprivation also disrupts appetite hormones. In another study, just two nights of four hours sleep dropped leptin, your satiety hormone, by 18%. Participants reported 24% higher hunger and stronger cravings for sugary, starchy foods. That’s your body’s way of saying, I’m tired, give me fast fuel.

[24:37 –> 25:10] And finally, when sleep is cut short, cognitive and motor performance plummets. Across 61 experimental studies, the average drop in cognitive performance was the equivalent of falling from fiftieth percentile of performance to thirty fifth percentile. That’s a significant drop in performance, especially for things like test taking where a score can have a substantial impact on your future opportunities in life. During sleep, your brain literally rehearses motor patterns, refining timing and coordination. In one classic experiment, people practiced a finger tapping sequence.

[25:10 –> 25:46] Without further practice, their speed and accuracy improved overnight purely by sleeping. That’s why athletes, musicians, and surgeons all performed better after quality sleep and why during my own neurosurgical training, I now see how irrational it was that we were expected to operate under chronic sleep deprivation while working on the most delicate anatomy in the human body. So sleep literally fine tunes nearly every system from your blood vessels to your metabolism to your mind. When we lose it, everything begins to unravel. But what happens when you finally get good sleep?

[25:46 –> 26:16] If sleep deprivation tears you down, restorative sleep builds you back up. Every night of full, high quality sleep is like running your body’s internal maintenance program, rebuilding tissue, resetting hormones, refreshing your brain, and recharging focus and mood. During deep sleep, your brain replays the day’s experiences through bursts of activity known as hippocampal replay. That’s how short term memories get transferred into long term storage, essentially how learning becomes permanent. Good REM sleep restores emotional balance.

[26:16 –> 26:37] It reconnects the amygdala, your brain’s emotion and fear center, with the prefrontal cortex, the seat of judgment and control. That’s why after a good night’s sleep, yesterday’s problems feel more manageable, and your emotional reactions are steadier. Quality sleep also rebalances your hormones. Growth hormone surges to repair tissue. Cortisol, your stress hormone drops.

[26:38 –> 27:12] Testosterone pulses return to normal, even your appetite hormones leptin and ghrelin reset to restore hunger and satiety balance. During sleep, the hypothalamus and pituitary synchronize through circadian and homeostatic cues, recalibrating every major hormone that governs growth, stress, metabolism, and reproduction. Athletes who extend their sleep show measurable improvements, faster reaction times, better accuracy, and greater endurance. That’s because muscles repair, tissue regenerates, and coordination sharpens while the brain rests. The body literally rebuilds as the mind sleeps.

[27:12 –> 27:37] Restorative sleep also recalibrates insulin sensitivity, strengthens immune memory, and lowers inflammation. Across massive population studies, people who sleep seven to eight hours a night live longer. Too little sleep and even sometimes too much sleep are both linked with higher mortality. Sleep is in many ways the most powerful antiaging therapy we have, and it doesn’t cost a cent. The takeaway is simple.

[27:37 –> 28:08] When you get enough sleep, every system in your body, cognitive, emotional, hormonal, metabolic, moves back into sync. Sleep is literally when your body upgrades, repairs, and restores itself. So now that we know what happens when you don’t get enough sleep, and how restorative sleep puts you back on track, Let’s talk about how to actually get that kind of restorative sleep, because that’s what we really wanna know. But before we get into the details on that, I wanna make one thing clear. I don’t generally recommend sleep medications as a first step.

[28:08 –> 28:40] Meds can knock you out, but they don’t build you up. They create unconsciousness, not restoration. Drugs like trazodone, antihistamines, or hypnotics give you more light stage sleep, but not enough of the deep or REM sleep that actually repairs the body, consolidates memory, and restores the metabolism. If you ever need medication, think of it only as a temporary bridge while you work on getting your own natural rhythm back. Now when it comes to getting truly restorative sleep, the first lever you need to pull is light.

[28:41 –> 29:07] If you wanna fix your sleep, don’t start with supplements. Start with light. Light is the single strongest signal to your brain’s master clock, the suprachiasmatic nucleus, that tells every cell what time it is. Morning light, especially within the first hours of waking, anchors your rhythm for the whole day. Getting bright outdoor light into your eyes within thirty to sixty minutes of waking is one of the most powerful things you can do for your circadian rhythm.

[29:07 –> 29:45] Morning light boosts your cortisol awakening response by about 35%, helping you feel more alert during the day and helping you fall asleep more easily that same night. Throughout the day, staying exposed to natural light keeps your rhythm stable, telling your body it’s still day. People who get more daylight and less light exposure at night fall asleep earlier and have fewer problems with insomnia. So just as morning light helps, evening light can actually hurt you. The light from the setting sun doesn’t cause problems, but indoor light, especially bright overhead LED lights, suppress melatonin and shortens its duration, effectively cutting your biological night short.

[29:46 –> 30:18] The worst offender is blue enriched light, the kind that comes from LED bulbs, TVs, e readers, and phones. It stimulates the same light sensitive cells in the retina that send signals straight to the suprachiasmatic nucleus, tricking your brain into thinking it’s still daytime. So on this topic, you’ve probably heard about blue light blocking glasses, and many people try to use these as ways to bypass the blue light problem in the evening. The truth is, they don’t make much of a difference for sleep. The most recent Cochrane review found little to no consistent benefit.

[30:18 –> 30:41] They can help with eye strain, but that’s about it. So rather than buying special glasses, change your lighting. Turn off bright overhead lights in the evening and use warm, low light at eye level like clamps and sconces. We once went all in on this concept as we had four kids under 10, and bedtime was always a hassle. We decided to turn off all electricity at sunset and light the house only by candlelight.

[30:41 –> 31:08] My wife wasn’t thrilled about this idea, but she humored me. On the day that we were playing to start this experiment, I came home late from the OR to find my wife Chosun sitting in the dark with four kids by candlelight. It’s fair to say that she was a little bit irritated, but the funny thing is the kids fell asleep instantly that night. We didn’t keep doing it, but it taught me that picking your light sources carefully in the evenings makes a huge difference in the quality of your sleep. The next factor is temperature.

[31:08 –> 31:35] About two hours before you fall asleep, your body’s core temperature naturally begins to drop. That drop is under control of the suprachiasmatic nucleus, which starts the cooling process as a cue for sleep. The faster your core body temperature drops, the faster you fall asleep. The body does this by sending warm blood to the skin, especially in the hands, feet, and face. If you keep your hands and feet warm, the blood vessels stay open and allow you to release heat more efficiently.

[31:35 –> 32:01] Wearing socks or keeping a blanket over your feet helps with this. Taking a warm bath or shower an hour or two before bed can also help because when you step out and start to cool down, your body dumps heat even faster. In studies, that post bath cooling shortened the time it took people to fall asleep by about ten minutes on average. You can also cool your environment. A bedroom temperature around 68 degrees Fahrenheit or about 20 degrees Celsius is usually ideal.

[32:01 –> 32:32] Too warm or too cold can both disrupt sleep, but a cool environment with warm extremities is the perfect combination. To optimize your sleep with temperature, I would say cool your room to 68 degrees Fahrenheit, take a shower before bed, and wear some comfortable socks. This will prime you for a nice core body temperature drop, which will induce restful sleep. The next thing to think about is caffeine. Most people metabolize caffeine with a half life of about four to six hours, which means it can take twelve hours or more to fully clear from your system.

[32:32 –> 33:02] That’s why it’s generally best to avoid caffeine eight to ten hours before bed. That said, everyone metabolizes caffeine differently. Some people who are very fast metabolizers can actually wake up in the middle of the night from caffeine withdrawal if they stop drinking caffeine too early in the day. For them, having a small amount of caffeine later in the evening can paradoxically help them stay asleep through the night. It’s counterintuitive, but it’s something to experiment with if you’re one of those people who wakes up at two or three in the morning and stops drinking coffee before noon.

[33:02 –> 33:26] The next level of pull is sleep time consistency. Consistent bedtimes and wake times train every clock in your body, from your brain’s master clock to the tiny peripheral clocks in your liver, heart, and pancreas. When your schedule swings wildly between weekdays and weekends, those clocks fall out of sync. That mismatch is called social jet lag. You haven’t flown anywhere, but your body feels like it has.

[33:26 –> 33:57] This internal desynchrony raises evening cortisol levels, disrupts metabolism, and keeps you wired when you should be winding down. Keeping a consistent sleep and wake schedule is one of the simplest and most powerful things you can do for long term health. And the last foundational lever you can pull is to lower your cognitive load before bed. One of the biggest drivers of insomnia is mental hyperarousal, going to bed with your mind racing essentially. Don’t dive into intense projects or emotionally charged conversations right before bedtime.

[33:57 –> 34:21] Give yourself time to wind down. Create a buffer between your day and your sleep. So at the end of the day, the most powerful levers for sleep are simple ones, light, temperature, sleep time consistency, and winding down your mind before bed. When you get those right, you’ve created a solid foundation for good sleep. Now if you’re one who struggles with insomnia, you might need extra help.

[34:21 –> 34:55] The best evidence based approach we have is cognitive behavioral therapy for insomnia, or CBTI. It’s a structured program that retrains your brain and your habits around sleep. It works by building sleep drive, reassociating bed only with rest, challenging unhelpful beliefs about sleep, and practicing relaxation techniques. It usually runs about four to eight weeks and has better long term outcomes than any medication we’ve ever studied. You’ll need to contact a therapist to get help with this, but if you suffer with insomnia, this is likely your best bet for getting back to normal sleep habits.

[34:55 –> 35:16] So now let’s say you’ve built the foundation that I talked about and still need a little extra help. This is where supplements can come in. I like to think of sleep supplements as working in tiers. The first tier includes those that have the best evidence, the lowest risk of side effects, and the most consistent results. The two I’d start with are magnesium and glycine.

[35:16 –> 35:52] Magnesium has been shown in double blind randomized trials of older adults with insomnia to improve sleep efficiency, total sleep time, and the time it takes to fall asleep. I generally recommend two hundred and fifty to three hundred milligrams of elemental magnesium in the evening about an hour before bed. Magnesium glycinate is my preferred form because it’s well absorbed and easy on the stomach. I take about two hundred and seventy milligrams myself at night, and I notice a difference in muscle relaxation and a smoother transition into sleep. Magnesium works by binding to GABA receptors, calming the nervous system and promoting muscle relaxation.

[35:52 –> 36:17] It also helps stabilize melatonin release through the night. If you’re on thyroid medication, make sure to separate it by at least four hours from your magnesium. The second supplement in the first tier is glycine. It shortens the time it takes to fall asleep, improves sleep quality, and can even help regulate body temperature at night. In studies, three grams taken thirty to sixty minutes before bed improved both sleep onset and next day alertness.

[36:17 –> 36:47] Glycine is safe, inexpensive, and well tolerated. It works by activating calming pathways in the brain, promotes a parasympathetic rest or digest state, and helps cool the body slightly, something that’s critical for entering deep sleep. Now if you build your foundation and added magnesium and glycine from the first tier of supplements but still find sleep difficult, you can move on to the second tier. These are okay to stack, but I would try them one at a time to see if you get benefit. The first is L tryptophan.

[36:47 –> 37:27] It’s an amino acid that your body uses to make serotonin, which then gets converted into melatonin. The interesting part is that tryptophan competes with other amino acids to get into the brain, and that competition limits how much can be converted into serotonin and melatonin. That’s why taking tryptophan with a small amount of complex carbohydrates, something like fruit or a slice of whole grain toast, can actually help. Insulin rises from the carbohydrates and drives competing amino acids into muscle cells, leaving more tryptophan in circulation that can cross the blood brain barrier and enter the brain. Clinical trials show that one to three grams of tryptophan before bed can shorten the time to fall asleep and reduce nighttime awakenings.

[37:27 –> 37:55] I generally recommend starting with one gram of tryptophan before going to bed and then going up to two and then possibly three grams before bed as an upper limit. I don’t recommend using tryptophan if you’re on an antidepressant medication like SSRIs, SNRIs, or MAOIs as as there’s a very rare complication called serotonin syndrome that can occur. The next supplement in tier two is L theanine. It’s especially useful when stress or anxiety are what keep you awake. It’s not a sedative.

[37:55 –> 38:30] It won’t knock you out, but it does help you relax. In one randomized controlled trial, adults taking two hundred milligrams of L theanine daily reported better sleep quality, less anxiety, and fewer depressive symptoms after eight weeks. I usually suggest taking two hundred milligrams in the late afternoon or an hour before bed, and you can safely increase up to four hundred milligrams if needed. L theanine basically works by balancing glutamate and GABA signaling in the brain and lowering your sympathetic fight or flight activity. If those don’t quite get you where you wanna be, there are a few additional supplements with milder or more variable effects.

[38:30 –> 38:51] I call these tier three supplements. They can be tried one at a time but should not be stacked. Ashwagandha has shown modest but measurable improvements in sleep quality and efficiency in meta analyses. Six hundred milligrams per day taken in the evening with food is typical. It’s calming and adaptogenic, and it’s fairly safe, but rarely it can cause liver issues.

[38:51 –> 39:14] So anyone with liver disease should check with their doctor first before taking ashwagandha. Saffron is another interesting one. Extracts standardized to about fourteen milligrams a day have shown small to moderate improvements in sleep quality and mood. It’s generally well tolerated but can occasionally cause mild digestive upset or headaches. Tart cherry extract has also been studied in older adults with insomnia.

[39:14 –> 39:44] It appears to slightly lengthen total sleep time and improve efficiency, likely because tart cherries contain small amounts of melatonin and increase the body’s own production. Drinking tart cherry juice for a couple of weeks improved sleep in one pilot trial, but the effect size was modest. Another supplement you might hear a lot about is apigenin, a compound found in chamomile. Some studies show small benefits for sleep quality, while others don’t show much effect at all. It’s mild, safe, and easy to try as tea or as an extract, but the evidence is weaker than for the others.

[39:44 –> 40:05] Finally, let’s talk about melatonin. Melatonin isn’t really a sleep supplement. It’s a timing signal. It tells your body when it’s time to sleep, but it doesn’t directly make you sleepy. For most people, melatonin should be reserved for situations where the circadian rhythm is misaligned, like jet lag, night shift work, or social jet lag from inconsistent schedules.

[40:06 –> 40:30] In those people, one to three milligrams taken thirty to sixty minutes before bed can help reset your rhythm. Short term use is safe, and longer term studies in healthy men haven’t shown changes in testosterone or luteinizing hormone. But in women trying to conceive, very high or prolonged doses could theoretically affect hormone cycles, so it’s best to use sparingly. Now I also wanna have a quick word about food timing. You’ve probably heard that eating late ruins your sleep.

[40:30 –> 41:01] In reality, studies show mixed results. Eating late doesn’t seem to impair sleep architecture in most people, but it can cause heartburn or reflux, which absolutely keeps you up. It also disrupts nighttime metabolism, raising glucose, delaying triglyceride peaks, and reducing fat oxidation. You’re essentially feeding the body when it’s supposed to be in a restorative phase. That being said, I subjectively feel worse sleep every time I eat late, so I always try to finish my meal by 7PM if possible, which honestly doesn’t happen every night.

[41:01 –> 41:23] If you can, finish your last meal at least three hours before bed. That’s metabolically sound, and it gives your digestion time to settle. And before we close, we have to talk about one of the biggest hidden causes of poor sleep, sleep apnea. Nearly thirty million adults in The United States have obstructive sleep apnea, and many don’t know it. It’s a silent disruptor that’s completely fixable.

[41:23 –> 41:54] During sleep, the airway intermittently collapses, dropping oxygen levels and forcing your brain to jolt you awake to restart breathing. These constant microarousals drive up sympathetic activity, heart rate, and blood pressure. That elevated stress tone carries into the daytime, causing hypertension, insulin resistance, and inflammation. People with untreated sleep apnea have higher rates of atrial fibrillation, metabolic disease, and daytime fatigue, and their risk of car accidents doubles. But the good news is that it’s mostly treatable.

[41:54 –> 42:26] CPAP and BiPAP devices can keep the airways open. There are also mouth guards that move the lower jaw forward and even implantable systems that stimulate the hypoglossal nerve to open the airway with each breath. The red flags to look for are loud snoring, pauses in breathing, gasping, morning headaches, daytime sleepiness, high blood pressure that’s hard to control, atrial fibrillation or type two diabetes. If you have any of these, it’s worth talking to your doctor about a sleep study. You can also start by taking the stop bang questionnaire, which screens for sleep apnea.

[42:26 –> 42:44] A score of three or higher means you should get evaluated. I’ll include a link to that questionnaire in the show notes. So before we wrap up this episode, let’s go over the things you can actually do to take control of your sleep. I always recommend a strong sleep foundation. This is where you start before you do anything else.

[42:45 –> 43:08] The first thing is to get morning light in your eyes within thirty to sixty minutes after waking. That single act coordinates your circadian rhythm for the whole day. You also need to avoid blue lights and overhead electric lights at night as they block your melatonin production. Second is to keep your room cool at night, around 68 degrees Fahrenheit or 20 degrees Celsius. This seems to be the sweet spot for most people.

[43:08 –> 43:28] You can also take a shower and wear comfortable socks in bed, which helps you lower your core body temperature and prepare for deep sleep. And third is to maintain sleep consistency. Go to bed and wake up at roughly the same time every day. That keeps your body’s clocks in synchrony. And fourth is to have a wind down routine before bed.

[43:28 –> 43:51] Give your brain permission to power down. And if you have chronic insomnia, talk to someone about cognitive behavioral therapy for insomnia. It’s one of the most effective treatments we have. Once those foundations are in place, then you can add supplements from the first tier, which includes magnesium and glycine. For magnesium, aim for two hundred and fifty to three hundred milligrams of elemental magnesium.

[43:51 –> 44:12] I prefer magnesium glycinate because it’s well absorbed and easy in the stomach. Take it right before bed. For glycine, mix about three grams of the powder into water and drink it thirty to sixty minutes before bed. Glycine helps cool the body and deepens slow wave sleep and reduces next day fatigue. If that’s not enough, the next tier would be L tryptophan and L theanine.

[44:12 –> 44:39] L tryptophan is the amino acid that becomes serotonin and then melatonin in your brain. It helps with faster sleep onset, especially in people who have trouble falling asleep. Start with one gram and increase up to two or three grams if needed. Take it with a small carbohydrate snack like fruit or a slice of toast with jam. That helps more tryptophan cross into the brain, but avoid it if you’re on antidepressants like SSRIs, SNRIs, or MAOIs.

[44:39 –> 45:11] L theanine promotes relaxation and smooth alpha wave activity. It’s great if racing thoughts or anxiety are keeping you up. Try two hundred milligrams in the evening, and if that’s not working, go up to four hundred milligrams. If those still don’t get you there, there are a few others you can experiment with one at a time in tier three. Saffron at fourteen milligrams a day, ashwagandha at six hundred milligrams a day, chamomile tea or apigenin extracts to be used as recommended on the bottles or the product, and tart cherry juice or tart cherry extract.

[45:11 –> 45:45] Don’t stack any of these, but try them one at a time and see how they work, and move on if they don’t work. Melatonin itself should be reserved for circadian rhythm disruptions, like jet lag, night shifts, or social jet lag from staying up late on the weekends. In those cases, one to three milligrams about thirty to sixty minutes before bed can help reset your rhythm. Just make sure you get a high quality third party tested brand since there have been discrepancies in studies showing that more or less melatonin is present in the supplement than recorded on the bottle. If you suspect sleep apnea, take the stop bang questionnaire.

[45:45 –> 45:59] If your score is high, talk to your doctor about a sleep study. Treating sleep apnea can dramatically improve your energy, focus, and long term health. Okay. That was a lot, but this information seriously can change your life. Sleep isn’t a luxury.

[45:59 –> 46:29] It’s maintenance for your brain, your hormones, your heart, your metabolism, your mood. When we sleep, the brain files memories, clears waste, and resets the emotional circuitry that allows us to meet the next day with balance. During sleep, the body can repair muscle, recalibrate hormones, and restores insulin sensitivity. But when sleep is cut short, the entire system begins to fray. Blood pressure rises, inflammation builds, glucose control slips, appetite hormones flip, and the brain loses its rhythm.

[46:29 –> 46:59] Even one week of short sleep can drop testosterone, raise cortisol, and blunt insulin sensitivity. Over time, it increases the risk of cardiovascular disease, diabetes, dementia, and depression, all because the body never gets its nightly rest. The good news is that sleep is one of the most reversible risk factors in medicine. When you restore it, blood pressure drops, metabolism stabilizes, memory sharpens, and emotional resilience returns. Sleep heals faster than almost anything else we can prescribe.

[46:59 –> 47:19] We live in a world that glorifies pushing harder, sleeping less, and powering through. But sleep isn’t weakness. It’s the ultimate performance enhancer. If you start treating your sleep with the same respect you give your work or your workouts, you’ll unlock capacity you didn’t know you had. When sleep works, everything else works better.

[47:19 –> 47:51] Alright. In the next episode, we’ll return to tribulations and go back to a time when diabetes was a death sentence, when the only treatment was starvation and parents watched their children waste away before their eyes. Then one sleepless night, a young surgeon scribbled an idea in his notebook, an idea that would save millions of lives. It’s a story that involves the kind of courage, curiosity, and altruism that medicine rarely sees anymore. This is a story you don’t wanna miss.

[47:51 –> 47:57] So until next time, stay curious, stay critical, and stay healthy. Cheers.