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When I was in my 20s, I didn’t think much about sleep. I felt that if I ate well, trained hard, and took the right supplements, I was good to go with health and fitness.

Today, I realize that sleep is often the deciding factor in whether or not someone succeeds.

When you think about it, most people should spend a third of their life sleeping. When you get that third right, the other two-thirds are more fun, productive, and healthier than they’d otherwise be.

Here’s everything you need to know to master the art of sleep.

The Phases of Sleep

You aren’t conscious of it, but while you sleep your body works hard to physically and mentally rebuild and repair itself.

Like the foreman on a job site who directs and organizes electricians, carpenters, and plumbers in a methodical process so they don’t interfere with one another’s work, your body divides sleep into different segments so it can effectively address one part of the body and then move onto another.

Throughout the night, your brain cycles through three stages of sleep: light, deep, and rapid eye movement (REM) sleep.

Each cycle lasts about 90 minutes. With normal sleep, you go through four to six cycles per night. The time you spend in deep and REM sleep — not just the amount of time you spend in bed — determines the quality of your sleep.

Most adults sleep in one large block of time, which is also called a monophasic sleep pattern. Children and the elderly do best with a biphasic sleep pattern, meaning they need a nap in the middle of the day to complement their nighttime slumber.

Light Sleep

During light sleep, you’re semi-conscious. You’re aware of your environment but only respond to something unexpected, such as the creaking of a door or your spouse whispering in your ear.

You have enough awareness to make sense of what’s happening, but are asleep enough that you don’t move unless you’re alarmed.

When you’re under a heavy amount of stress you can spend most of your night in this phase, missing out on the benefits of the next two phases.

Deep Sleep

Deep sleep supports the growth and repair of your body.

Provided you remain in light sleep without interruption, you enter deep sleep about 10 to 30 minutes later.

Deep sleep supports your body’s physical recovery, whereas REM sleep supports your brain and mind. In deep sleep, you lose your ability to regulate your body temperature, which is why it’s so important to sleep in a cool bedroom whenever possible.

During this phase, growth hormone rises, supporting tissue repair, fat metabolism, and many other positive health effects. Though dreams sometimes occur during deep sleep, it is rare.

In a typical night, you enter deep sleep three to five times.

Rapid Eye Movement (REM) Sleep

REM sleep supports the growth and repair of your brain.

The last third of the night, assuming you get a full night’s sleep, is dominated by REM sleep. In total, it makes up 20 to 25 percent of your sleep time.

REM, which follows deep sleep, is your dream state (it was also a great band in the ’80s and ’90s). It’s when your vibrant, funny, terrifying, exciting, and disturbing dreams occur.

A burglar would have the best chance of stealing something in this stage because you don’t hear anything, and your muscles are temporarily paralyzed. This happens so you don’t act out your dreams and knock out your bed partner.

It’s in REM that your brain tries to make sense of the information from the previous day. It deals with anything that’s been on your mind. Your memories are consolidated, and your brain is actually “washed” in cerebral fluid to help remove toxins.

REM sleep time varies throughout the seasons. The average person gets about 16 percent more REM sleep in the winter than in the middle of the summer.

Neurogenesis, the growth of new brain cells, takes place during REM. Throughout life, we lose and rebuild brain cells, but chronic sleep deprivation limits the brain’s ability to generate new brain cells.

Interestingly, penile erection and clitoral swelling occur during REM sleep as well. For men, lack of a morning erection is usually a sign of either low testosterone or insufficient REM sleep.

One other thing worth mentioning: Your brain takes priority during the night, so if you get behind on sleep quality, you’ll spend a disproportionate amount of time in REM compared to deep sleep until you catch up on your REM. That means you’ll have a hard time recovering from exercise and physical stress if you don’t get enough sleep for your brain to recover.

How Much Sleep Do You Need?

GroupAgesIdeal Sleep
Older Adult65+7–8 hours
Adult18–647–9 hours
Teenager14–178–10 hours
School Age6–139–11 hours
Preschool3-510–13 hours
Toddler1–211–14 hours
Infant4–11 months12–15 hours
Newborn0–3 months14–17 hours

What Happens During Sleep?

The following table outlines what happens with your hormones and neurotransmitters at night.

Hormone / NeurotransmitterEffects During Sleep
Growth HormoneHighest secretion of 24-hour cycle occurs during deep sleep, and is secreted in pulses with each cycle back into deep sleep.
ProlactinRises about 30 to 90 minutes after onset of sleep.
Thyroid Stimulating Hormone (TSH)Peaks in evening before sleep, and decreases throughout the night, suggesting that thyroid hormones (T3 and T4) rise as night progresses.
TestosteroneIn men, secretion is lowest at about 8 p.m., and peaks about 8 a.m. (which is why it’s best to get blood testing done first thing in the morning).
MelatoninRise begins at bedtime and peaks between 3 a.m. and 5 a.m.
LeptinIncreases to curb appetite.
Cortisol, Epinephrine, NorepinephrineStress hormone and neurotransmitters decrease during sleep; they rise leading into the morning wakeup time.

Melatonin and Sleep

You can’t have a conversation about sleep without bringing up melatonin. Melatonin is the hormone of darkness, and is created from the amino acid l-tryptophan.

The pineal gland secretes melatonin at dusk, and levels continue to rise until midmorning. Moderate levels of stress or exercise enhance your ability to secrete melatonin, but its cyclical ebb and flow is often disrupted in people with poor or inconsistent sleep patterns.

Melatonin secretion decreases with age, which could be part of the reason older adults sleep less.

Melatonin supplementation can be beneficial when traveling across time zones, adjusting to a new sleep schedule, or for older adults.

In addition to supporting sleep, melatonin has been shown to support healthy cholesterol levels, normal inflammatory levels, and can support restful sleep, especially in those with neurodegenerative diseases, depression, chronic fatigue, fibromyalgia, headaches, and insomnia.*

Melatonin stimulates brown adipose tissue while inhibiting insulin production from the beta-cell (insulin-secreting cells of the pancreas). By doing so, melatonin may control body weight via changes in body temperature and energy expenditure whereas, by inhibiting insulin production at night, may favor beta-cell rest. We suggest that prolonging our days with artificial light may favor obesity by inhibiting melatonin production, thus silencing the brown adipose tissue, and may also impair insulin production in the long term by prematurely exhausting the beta-cell.

Cizza, et al.

Consequences of Sleep Debt

“You don’t need so much sleep. Sleep when you’re dead.”

The first time I heard that ridiculous piece of advice, I was in the locker room at the Olympic Training Center in Lake Placid, N.Y. I’d asked one of the ski jumpers on the U.S. Olympic team how he fit in all his training while going to school and still having plenty of time for fun.

Unfortunately, I’ve heard people say the same thing too often to count over the years.

In some messed up way, we often think that we can outsmart our own physiology — that the health risks of insufficient sleep don’t apply to us. If that’s what you believe, it’s time to stop deceiving yourself.

The term “sleep debt” paints an accurate picture of what you do to your body when you either sleep too few hours each night, or when you get enough hours, but you don’t achieve deep restorative sleep.

Effects Of Sleep Debt
Elevated Cholesterol Reduced Testosterone
Insulin Resistance Obesity
Metabolic Syndrome Type 2 Diabetes
Elevated Cortisol Muscle Loss
Increased Appetite From Leptin & Ghrelin Dysfunction Disrupted Gut Bacteria
Depression Increased Inflammation
Reduced Immune Function Increased Pain Sensitivity
Decreased Libido Body-fat gain

In the past, it was thought that people who got insufficient sleep ate more and moved less, and that caused weight gain. It turns out, weight gain isn’t necessarily a result of excess calorie intake and too little movement. In fact, insomnia increases metabolic rate — one study showed a year of insomnia increased resting metabolic rate by a whopping 11 percent.

Yet, even though insomnia raises metabolic rate, those with insomnia still tend to gain fat, even when they eat well and exercise appropriately. That shoots another hole in the “calories in, calories out” hypothesis.

Weight gain from sleep debt isn’t a calorie balance problem. It is a hormonal balance problem.

One night of disrupted sleep causes insulin resistance the next day. Two nights of insufficient sleep causes mood deterioration, which is caused by dysfunction in the medial prefrontal cortex (MPFC). A week of getting only five hours of sleep decreased testosterone by 10 to 15 percent in men.

In women with sleep debt, for each additional hour of sleep they got, their likelihood of having sex the next day increased by 14 percent, suggesting sleep debt robs you of your libido.

Animal research shows sleep debt increases sensitivity to pain. This means that as you lose sleep, aches, pains, and conditions like fibromyalgia can get worse.

The liver produces more than 600 metabolites. About 60 percent of them depend on a normal circadian rhythm.

Long-term sleep debt can cause cognitive decline. Also, many neurodegenerative diseases like Alzheimer’s or Lewy body dementia cause reductions in deep and REM sleep. The loss of REM sleep further contributes to cognitive decline.

Shift Work and Sleep

Cortisol is at the crux of the shift-work problem. Your cortisol should reach its peak once per day, just as you wake up. However, if you wake up at one time for a job during the workweek, and a totally different time on the weekends, you disrupt the normal cortisol rhythm and cause chronically elevated levels.

Constantly elevated cortisol levels cause weight gain, especially in the belly, along with the following:

  • Muscle loss
  • Increased heart disease risk
  • Inflammation
  • Immune system suppression
  • Cognitive dysfunction
  • Mood changes

If you are a shift worker who wants to maintain your health and avoid obesity, you must stick to a consistent, seven hour (or more) sleep schedule with a consistent bedtime every night, and avoid the temptation to snack on convenience foods and energy drinks.

While you can use supplements and nutrition to minimize the negative impact of shift work, sticking to a consistent schedule is the most important.

Causes of Sleep Debt and What You Can Do About It

Your body has an internal clock, which, when it’s working well, determines the ebbs and flows of hormones and neurotransmitters, manages many of your body’s systems, and guides you to sleep, wake up, nap, and move. Your internal clock is found in the suprachiasmatic nucleus (SCN).

Your environment also affects your circadian rhythm. The external influences on your circadian rhythm are called zeitbergers. Light is the most powerful zeitberger, but diet, exercise, and supplementation also influence the SCN.

You don’t want to mess with your circadian rhythm. To give you an idea of what one lost night of sleep can do, look at the effects of shifting the clocks forward one hour for Daylight Savings Time:

Heart attack rates jump 25 percent the Monday after the clocks change due to Daylight Savings Time.

Most of the causes of sleep debt below directly or indirectly affect the SCN. I’ve listed the causes of sleep debt, starting with the most obvious and ending with causes you might not think of. Often, it’s the obvious causes people overlook.

Inconsistent Bedtime

For your circadian rhythm to have a rhythm, you have to be consistent about when you go to sleep.

Melatonin secretion initiates the process of putting you to sleep. But if you keep yourself up with artificial lights, digital screens, and stimulants, eventually your body stops producing melatonin like it’s supposed to. Then, when you want to go to sleep on schedule, you won’t be able to.

When improving sleep, the most important thing you can do is to go to bed at a consistent time every night.

If you have a hard time falling asleep, read a book. Your brain waves while reading are similar to sleeping, which is probably why so many people find it easy to fall asleep after a few pages of reading, but can stay awake for hours while watching a movie in bed.

Bedroom Temperature

The ideal temperature for sleep is 67 to 69 degrees F. If you’re going to err on one side or the other, go with a cooler over a warmer bedroom.

It is possible to go too low with the temperature. If you get too cold, your body won’t get into REM sleep — this is a survival mechanism common among mammals. You wouldn’t want to be dead to the world because you’re in a dream while your body is literally freezing to death.

Alcohol Consumption

If you imbibe to settle your nerves and calm your mind, alcohol might help you fall asleep, but it can negatively affect the benefits of sleep.

Drinking “every once in a while,” compromises your REM sleep the night you drink. Interestingly, those who drink every night seem to regain their REM sleep as they develop a tolerance to alcohol. So, periodic alcohol consumption compromises REM sleep, but regular drinking does not.

Before you justify getting jingled each night, know this: Regular drinking suppresses growth hormone. Low growth hormone leads to muscle loss and fat gain, which explains why regular drinkers often end up with big (a.k.a. “beer”) bellies and scrawny arms and legs.

Disruptive Bed Partner

Whenever I get a cold, I sleep on the couch. Whenever my wife, Vanessa, gets a cold . . . I sleep on the couch. (We do have an extra bedroom, but I never sleep in there because I don’t want to make the bed in the morning.)

If you sleep with someone who snores, coughs, tosses and turns, or has restless leg syndrome, you’re going to pay for it with interrupted sleep. While I’m not a fan of having separate bedrooms, if your significant other wakes you up throughout the night, your ability to spoon him or her might not be worth the sacrificed sleep.

Try earplugs to drown out the noise. Suggest that he or she take magnesium to reduce the restless legs. Do whatever you can, and whatever they’re willing to do to be a better bed partner — but don’t sacrifice sleep night after night if they can’t stay still and silent.

Sleep Apnea

It’s estimated that half of adult women and a significant percentage of men suffer from sleep apnea. Excessive body fat is the most common cause of sleep apnea.

As people gain body fat, their necks and throats gain fat, too. The extra fat presses down on the soft tissue in their mouth and throat as they sleep, blocking airflow.

Most of the time, the lack of oxygen wakes them up. This happens multiple times each night, causing interrupted sleep, which contributes even more to their weight gain.

While a CPAP is helpful, it is not a long-term solution. If you’re overweight and have sleep apnea, using a CPAP is like someone with type 2 diabetes using insulin — it deals with the symptom but does nothing to fix the cause.

Lose the weight so you can breathe when you sleep.


In many ways, the word stress has become as synonymous as the word struggle.

Perhaps it’s because most of us have never faced major stressors. Or, it could be that we have so many minor inconveniences we fret about, that our minds feel overwhelmed with irritation. Then again, it could also be the fact that so many people describe their lives as stressful, that we exaggerate our own issues just to fit in, or one-up someone else on social media.

I digress. My point is that when it comes to stress, it isn’t really the events or circumstances themselves that cause stress, it’s our interpretation and perspective of those situations.

The solution to better sleep isn’t to avoid stress. The solution is the skill of handling the stress.

You can meditate, pray, or take a long walk as a mental break from your stress. If there’s something you can do about whatever is causing you stress, then do it. If there isn’t anything you can do, then let it go.

Holding on to stress — and the emotions that accompany it — causes a cascade of hormones and neurotransmitters that keep you from sleeping well. It disrupts your metabolism and can lead some people into adrenal fatigue.

While you work out the details on how you’ll handle the stress, the following supplements have been shown to help reduce feelings of stress, calm your mind, and/or support more restful sleep.

Supplements That Support Stress Resilience

Relora®: Relora is a combination of Magnolia and Phellodendron extracts. I was first introduced to Relora by Dr. Jim LaValle, author of Cracking the Metabolic Code. Relora has been shown to support normal stress hormone levels, relieve feelings of tension, anger and fatigue, and supports feelings of vigor and good mood.*

Essential oils: A number of studies show essential oils support a normal stress response, calm the mind, and support sleep. They include the essential oils of bergamot, orange, lavender, lemon, rose, cedar, Roman chamomile, angelica, and ravensara.

Magnesium: Magnesium has numerous effects on the body and brain, one of which is to help calm the mind.

Low magnesium levels dampen serotonin production, so if your magnesium is low, supplementing with magnesium malate may help you calm your mind and get to sleep.*

Hemp oil: Smoking dope could help you sleep, but the recreational use of marijuana doesn’t really fit with a healthy way of life. Fortunately, you can get most of the benefits of Mary Jane, including the support of sleep, without needing to spark a bowl by using hemp or CBD oil. Hemp oil and other phytocannabinoids have been shown to reduce feelings of stress and support better sleep.


Coffee is good for you, but not when you drink it too late in the day. At least, it’s not a good idea to drink caffeinated coffee too late in the day. More often, the issue isn’t coffee, though. It’s other stimulants like energy drinks and pre-workout supplements.

The top consumers of energy drinks are adolescents, but many adults rely on energy drinks as well. Often, the energy drinks create a faster and greater mental stimulation — and a faster and greater crash — than coffee.

Coffee contains dozens of other compounds, which is why most people will notice a greater effect on their heart rate and feel more jittery from a caffeine pill than from drinking a cup of coffee with an equal amount of caffeine.

If you have the habit of using a stimulant before your workouts, and you exercise in the evening, wean yourself off of them. If you get better sleep, you might not be so tired before your evening workout.


Cushing’s syndrome, Addison’s disease, adrenal insufficiency, and adrenal fatigue cause abnormal cortisol rhythms and are all associated with disrupted sleep. Nutrition, supplementation, and the right type of exercise play roles in mitigating the negative effects of too much or too little cortisol.

You can work your way toward a more normal cortisol rhythm, and resilience to stress, but it takes months, and sometimes years. Patience and persistence.

Frequently Asked Questions

Whenever we talk to people about changing their sleep habits, we’re often asked the following questions. Since they weren’t specifically addressed above, I’ll briefly cover them here.

(Of course, you can continue the conversation in the Life Time Training Facebook group.)

Can I make up for my sleep debt during the week by sleeping in on the weekends?

No. According to the research, you need to be consistent with your sleep. Sleeping in a couple of days per week won’t resolve the problems associated with your sleep debt from the other nights.

Is there anything else I can do to improve the quality of my sleep?

Other than what’s covered above, I’d recommend the following:

Eat dinner a few hours before bedtime. Insulin levels should be back to baseline by then, allowing you to fall asleep faster.

Block blue light. Exposure to blue light interferes with melatonin production. Many smartphones and laptops now have settings that allow you to shut off the blue light at night. It changes the color of the screen, but it’s worth it so you don’t sacrifice sleep.

Get a pair of blue-light-blocking glasses. I’m wearing a pair of Felix Gray glasses right now as I work on this article.

Make your room as dark as possible. Block all lights, including those from your devices. Your skin senses light even when your eyes are closed. Research shows it can interfere with sleep quality.

Finally, take a warm bath about 90 minutes before bedtime. The bath increases your core temperature. In response, your body increases blood flow to cool itself. When you get out of the bath, your body continues to cool itself, which drops your core temperature a bit below normal, aiding in sleep quality.

I have kids. How do I get more sleep when they’re up so late?

A teenager who goes to bed at 9 p.m. and wakes up at 6 a.m. gets 10 hours of sleep. That’s the recommended amount in the table above.

Vanessa and I felt it was important to lead by example for our kids when they were growing up. We went to bed at 9 p.m., so our sons did, too. There was no other option. If your kids are up too late to get enough sleep, that’s on you as the parent.

I also realize some kids are in sports practice past 9 p.m. Do what you can to minimize the late nights, as their brains and bodies are in the middle of an important growth period — they need sleep.

Sleep Like a Boss

Laugh and the world laughs with you, snore and you sleep alone.

Anthony Burgess

2,555. That’s the number of hours, at a minimum, you should sleep each year as an adult.

Just as a plane can end up miles from its destination by flying just a degree or two off from its course, you can end up far from healthy and fit by sacrificing just a little bit of sleep night after night.

A year of falling 30 minutes short each night is 182.5 hours — more than an entire week of lost sleep.

If you got to the end of this long article, and didn’t fall asleep, congrats. My goal isn’t to just write something that’s interesting to read, though.

I wrote this to challenge you to take your sleep more seriously. You can always make money back. You can almost always find time to watch another show, or post a status update on social media. But you can never get back your time.

The hours you lose from sacrificing sleep are gone forever. Starting tonight, stop going further into debt, and make the most of the nights ahead of you. Sleep well.


Keep the conversation going.

Leave a comment, ask a question, or see what others are talking about in the Life Time Health Facebook group.

The Life Time Health Team

Thoughts to share?


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