Why Sleep Should Be a Part of Your Training Plan

Sleep- one of four biological needs (the others being: eating, drinking and mating). So important to our overall health that the Guinness World Records no longer recognizes this category because long term sleep deprivation has been shown on multiple occasions to pose serious and permanent health risks, both physically and mentally. 

Take for example the infamous sleep deprivation experiment in 1959 by New York DJ Peter Tripp. He locked himself in a glass booth located in Time Square and made it 201 hours (8.4 days) before falling asleep (the last 66 hours he required stimulants to remain awake). On day 3, Tripp was found laughing hysterically at nothing, and following that day, he continued to hallucinate, reporting mice and kittens running around the room. By the end of the experiment, Tripp was convinced that he was no longer himself, but an impostor. After the experiment ended, Tripp’s family reported permanent changes to Tripp’s personality, including moodiness and depression.

Sleep has been shown to have a direct impact on overall health, lifespan, productivity, safety and ability to learn. Sleep is one of the top five reasons that patients visit a clinic for care every year and lack of sleep has been associated with an increased risk of type 2 diabetes, cardiovascular disease, Alzheimers disease, and even cancer. Along with being an integral part of the recovery and adaptive process between bouts of exercise, accumulating evidence suggests that increased sleep duration and improved sleep quality in athletes are associated with improved performance and competitive success.

This week, we’re focused on sleep. Why? Because it’s something that everyone, especially athletes, tend to neglect when we get busy. We think that shortening our sleep by just one hour will help us get more done, and won’t really affect our health and/or performance. But will it? With COVID thrusting many athletes into an early off season, now is the PERFECT time to start working on finding YOUR perfect sleep routine. To convince you why this is so important, we’re going look at the physiology of sleep, but also the consequences of not getting enough quantity and quality sleep, how to get more (and better) sleep, what to do if your life isn’t set up for optimal sleep, and why prioritizing sleep is something you want to do right now to help your performance in the future!

The Science Behind the Circadian Rhythm
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In order to optimize our sleep and wake cycle, we must understand our biological clock, also known as our circadian rhythm. Inside of the hypothalamus, deep inside our brain, lies a group of nerves called the suprachiasmatic nucleus (SCN). This group of nerves is made up of approximately 20,000 neurons and is responsible for generating neurotransmitters that regulate bodily functions, such as core body temperature, blood pressure, hormonal regulation, digestion, metabolism, brain wave activity, and arguably the most important feature of all, the sleep and wake cycle. The SCN regulates these bodily functions in a timely rhythm, known as our circadian rhythm. Every organism on the planet has been shown to have a circadian rhythm, including plants, bacteria, fungi and mammals. Across all of these organisms, scientists have found that specific genes (although different in each species) are responsible for establishing this biological rhythm. The circadian rhythm is a natural, internal clock that repeats itself in an approximately 24-hour cycle. Although it is established by genes and is internally driven, the circadian rhythm is influenced by the external environment, most specifically by light and temperature. It is thought that the circadian rhythm is established in species as an evolutionary selective advantage. The timely prediction of seasonal weather conditions, food availability, or predator activity is crucial for survival of many species. We most commonly see the circadian rhythm play out in nature among species who have regular migratory, hibernating, and reproductive patterns.

Since our circadian rhythm affects everything from our digestion and appetite, to blood pressure and sleep, a circadian rhythm disruption can have some serious consequences on recovery after exercise and overall health. A study on mice published in 2005 showed the health effects of mutations to a gene that aids in regulating the circadian rhythm in mice, known as Clock. In the study, Clock gene mutant mice were shown to have a greatly altered diurnal feeding rhythm, were excessively hungry, became obese, and developed many metabolic syndromes including hyperlipidemia (an abnormally high amount of fats in the blood) and hyperglycemia without proper insulin production (the hallmark of type 2 diabetes). These results indicate that the circadian Clock gene network plays an important role in mammalian energy balance that involves a number of central and peripheral tissues, and disruption of this network can lead to obesity and the metabolic syndrome in mice.

There are several studies that have looked at how a disrupted circadian rhythm can affect endurance performance, most of which have demonstrated that sleep deprivation inhibits performance. In a small study of 11 male subjects who completed a 30 minute self-paced treadmill test after a normal night sleep and again after 30 hours of sleep deprivation in a randomized order, the subjects distance covered was decreased after sleep deprivation, without differences in thermoregulatory function or oxygen consumption. Several other studies on endurance athletes have found a decrease in time to exhaustion along with an increased rate of perceived effort after just one night of reported poor quality sleep. Preexercise muscle glycogen stores have also been found to be decreased after sleep deprivation, suggesting an alteration in endogenous fuel availability that could translate into impaired performance in endurance sports.

With so much evidence leaning towards optimizing sleep to improve athletic performance and optimized health, there is no reason why learning more about how you can optimize your sleep routine shouldn’t be a focus of your off-season. The off-season is a perfect time to test different activities, methods, foods, workouts, etc to find what works best for your body. N=1 couldn’t be more true in this situation. For one person, eating dinner at 7pm may not affect their sleep whereas another person may not get into deep sleep if they eat after 5pm. Use the quality time you have WITHOUT a race on your calendar to fine tune your sleep routine.

The Sleep Cycle
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Our sleep cycle is one of our many circadian rhythms. Our sleep cycles occur in approximately 90 minute cycles and consist of 2 major states: REM and non-REM. REM, standing for rapid eye movement, is the sleep phase where our brain waves are active and resemble similar brain waves as wakefulness. Non-REM, standing for non-rapid eye movement, is the phase of sleep measured by calm brain waves and little to no eye or muscle movements. These 2 states can be further broken down into 4 distinct and measurable phases:

Non-REM Stage 1
Starts at the onset of sleep and lasts for approximately 20 minutes. In stage 1, our heart rate slows down, our temperature begins to drop, and our brain transfers learned muscle memory into permanent memory. Stage 1 of Non-REM sleep is very light sleep and one can be easily woken in this stage.

Non-REM Stage 2
This is the transitional period between light and deep sleep.

Non-REM Stage 3
This stage is considered complete deep sleep. In stage 3, Delta brain waves are produced which help move blood to the muscles to initiate recovery and repair, the parasympathetic nervous system is stimulated which supports immune function, and human growth hormone is produced.

REM Stage 4
Stage 4 is considered REM sleep and the stage in which we dream. In stage 4, the hippocampus (part of the brain) transfers information to the neocortex and our memories are formed.

A full night of sleep is important because the stages are not divided equally throughout the night. In the early hours of sleep, the majority of our sleep is made up of non-REM sleep and very little REM sleep. In the second half of a night's sleep, our cycle shifts to be mostly REM sleep and less non-REM sleep. Non-REM sleep is deeper and more restorative than lighter, dream-infused REM sleep. Additionally, the major period of human growth hormone release occurs during the first period of stage 3 non-REM sleep during the night, about an hour after you first fall asleep.

 These are just some of the reasons that Dr. Matthew Walker, head of the Sleep and Neuroimaging Lab at the University of California, Berkeley, and other sleep experts say that sleeping from midnight until 8am is not the same thing as sleeping from 10pm-6am because the shift from non-REM to REM sleep happens at certain times of the night regardless of when you go to bed. If improved memory and tissue growth/repair isn’t enough of a reason to get to bed early, maybe learning more about the consequences of poor sleep will be.​

​Consequences of Poor Sleep
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There are hundreds of studies that have been completed since the 1950’s to show the systemic consequences of poor sleep on humans (and other animals). Dr. Michael Twery, a sleep expert at NIH, states that “poor sleep affects growth and stress hormones, our immune system, appetite, breathing, blood pressure and cardiovascular health.”

Here are a few studies, which are reminders that things like blood sugar, weight, and memory are not affected from our diet alone!

Blood Sugar/Insulin Resistance

A study performed at the Leiden University Medical Center took 9 healthy individuals, with healthy blood sugar response, and restricted sleep for one night (subjects were allowed to sleep from 1am to 5am). The result was insulin resistance in multiple metabolic pathways in all subjects.

Data from large published studies, including: Sleep Heart Health Study; Finnish Type 2 Diabetes Study; Quebec Family study; Behavioral Risk Factor Surveillance System; National Health Interview Study; and Isfahan Healthy Heart Program, have all demonstrated that middle-aged to elderly subjects with self-reported short sleep duration are approximately twice as likely to be diagnosed with type 2 diabetes and are at higher risk for impaired glucose tolerance.

Weight Gain

A 2004 study took 1,024 volunteers from the Wisconsin Sleep Cohort Study, a population-based longitudinal study of sleep disorders, and looked at morning fasted blood samples for serum leptin and ghrelin (two key opposing hormones in appetite regulation), adiponectin, insulin, glucose, and lipid profile. Results showed that participants with sleep shorter than 8 hours per night had reduced leptin  (the satiation hormone) and elevated ghrelin (the hunger hormone) as well as higher BMI.

Immunity

A study published in 2009 took 153 healthy men and women and had them report on sleep duration and sleep efficiency for 14 days. Subsequently, participants were quarantined, administered nasal drops containing a rhinovirus, and monitored for the development of a clinical cold for 6 days. Results showed poorer sleep efficiency and shorter sleep duration in the weeks preceding exposure to a rhinovirus were associated with lower resistance to illness.

Death

A study published by the University of Bristol which examined working men and women looked for the associations between sleep duration, cardiovascular disease risk factors and mortality, while also taking into account the perceived stress of the individuals. The findings: the men and women who reported sleeping fewer than 7 hours in a 24 hour period had greater risk of dying from any cause over a 25 year period than those who reported sleeping 7-8 hours in a 24 hour period. 

9 Foundations of Sleep
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To optimize your performance, health, productivity, lifespan, safety and ability to learn, not only do you need to get regular sleep, but that sleep needs to be quality sleep. 

To ensure the right quantity and quality of sleep, there are some sleep foundations you should follow:

Follow a sleep schedule. Every single night at the same time, you should start a series of actions that should stay the same from night to night. The sun setting can be a good trigger to start this routine in the winter, however, in the summer when days are long, setting a standing alarm can help remind you that it’s time to finish eating, put on your blue light blocking glasses, turn off all screens and start winding down.

Eat a diet that promotes quality sleep at the right times.

• Eat a dinner full of melatonin rich foods, such as: tart black cherries, almonds, walnuts, corn, rice and ginger root.
• Avoid caffeine, including chocolate after 12pm
• Avoid alcohol before bed
• Avoid large meals and beverages 2 hours before bedtime

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Avoid intense exercise 2-3 hours before bedtime. If your fasted morning blood sugar is higher than ideal, choose 20-30 minutes of a relaxing activity before bed, like gentle walking.

Get your daily dose of natural sunlight for a minimum of 30 minutes per day. If you work in front of a computer all day and wear blue light blocking glasses, make sure you take them off periodically throughout the day and allow your eyeballs to see the natural sunlight. If you can not get out into the natural sun, consider morning exposure to artificial light for at least 1 hour.

Only nap before 3pm.

Schedule time for relaxation for at least 20 minutes before bed. Espom salt baths, foot soaks, reading and meditation are all great options.

Create a bedroom that is most conducive for proper sleep.

• Avoid electronics in the bedroom
• Create complete darkness
• The general suggested temperature for an ideal night's sleep is between 60-67 degrees Fahrenheit.
• Invest in comfortable and non-toxic clothing, pillow, mattress and linens.

Avoid medications that cause stimulation before bed. Some examples of these medications are hypertension, allergy, and thyroid medications. Consult with your doctor about options for taking these medications at earlier times of day in order to optimize your ability to sleep.

Don’t stay in bed if you haven’t fallen asleep after 30 minutes. Instead, move to another room and do something relaxing, like read a paperback book. Avoid jumping onto your phone to check social media, emails or play games. Once you start to feel tired again, move back into bed.

​If you are consistently following the 9 sleep foundations above, and are still experiencing constant fatigue and irritability during the day after getting 7-9 hours of sleep, waking up several times during the night, staying awake for more than an hour without being capable of falling back to sleep, or taking longer than 30 minutes to fall asleep, it might be time to seek out a sleep specialist for help.

Helpful Tools for a Good Night's Sleep
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There are several tools that can help you assess your quality and quantity of sleep, along with helping you learn more about why it’s so important. 

For more info on the topic of sleep, I love Matthew Walkers book, Why We Sleep: Unlocking the Power of Sleep and Dreams. He also did a really great podcast with one of my favorite doctors, Dr. Peter Attia which you can find HERE. 

If you think you’re getting enough quality sleep, but aren’t quite sure, definitely look into getting an Oura Ring. The Oura Ring is exactly that, a ring that you wear every day and every night that tracks everything from heart rate, body temperature, HRV, sleep cycles and more. Oura interprets these signals while you sleep so you can wake up to the insights you need to take on the day. With the data, you are empowered to understand and define your health on your terms, based on your personalized data. I have personally been using an Oura ring now for over a month and have already been surprised at how small changes to my evening routine have had a profound effect on my deep and REM sleep (and therefore my recovery).

Temperature has a pretty pronounced effect on your sleep cycles. If you share your room and/or household with someone who doesn’t love the bedroom between 60-67F, consider getting a Chili Pad. This pad lives between your mattress and your sheet and can help control the temperature on your side of the bed. You can even set the temperature to increase in the early morning hours to wake you up peacefully. Say goodbye to the BEEP BEEP BEEP alarm. That’s a terrible way to wake up!

In Summary
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I get it, we’re all busy. But in a time when training doesn’t have to be our tip top priority, doesn’t it make sense to focus on a few other things that can help make you a healthier human being?

By taking the time now (while you have it), to learn more about what helps you get better sleep (which translates into better performance) you can apply your own best practices when it matters most.

Sure, eating dinner at 5pm may not be your reality year around, but if you find that eating early unlocks more deep and REM sleep, don’t you want to make that a priority during your hard training weeks and leading into your future events?

Now’s the time to start playing and tracking some metrics. If you can’t afford a trackable device like an Oura ring, start a journal.

​Change 1 thing for 7 days in a row and see if you notice a difference in how you feel the next day in regards to your energy, recovery, mood and hunger levels. You might be surprised how small changes can have a big impact on your health and performance!

RESOURCES:

1. https://link.springer.com/article/10.1007/s00421-009-1103-9
2. https://journals.lww.com/acsm-msse/Fulltext/2011/07000/Intermittent_Sprint_Performance_and_Muscle.22.aspx
3. Mesarwi, Polak, Jun and Polotsky, Sleep disorders and the developments of insulin resistance and obesity. Endocrinology Metab Clin North Am. 2013 Sep; 42(3): 617-634
4. Taheri S, et al. Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index, 2004
5. Cohen S, et al. Sleep habits and susceptibility to the common cold, 2009​
6. Heslop P, et al. Sleep duration and mortality: the effect of short or long sleep duration on cardiovascular and all-cause mortality in working men and women, 2002