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Sleep, The Hidden Advantage for Performance by Ashley Reaver, MS, RD, CSSD

Sleep, The Hidden Advantage for Performance by Ashley Reaver, MS, RD, CSSD

Athletes are always looking for a way to improve their performance. Whether it’s an updated bike, a different fueling strategy, or a new coach, athletes are willing to invest their money in things that could lead to a better outcome. Interestingly, the investment that is likely to have the biggest impact on performance is free: sleep!

An ideal night’s sleep

Sleep includes three distinct phases: Light sleep (Non-REM 1 & 2), Deep sleep (Non-REM 3), and REM sleep. One cycle includes passing through all 3 phases and typically lasts about 90 minutes. Most people have 4-5 sleep cycles per night, depending on the length of sleep. It is recommended that adults sleep 7-9 hours per night. In theory, this allows for 5 sleep cycles to take place.

Sleep and performance

Each of the sleep phases is important. When entering light sleep, your brain starts to shut down the conscious part. This frees up resources to restore and repair other parts of the brain. Light sleep is also the sleep phase entered during naps. Even just a 20-minute nap is shown to increase alertness and cognitive functioning. For athletes, this translates to reaction times and reflexes. Deep sleep is believed to be responsible for the storage of short-term memories into long-term memories.


REM sleep has the biggest impact on our performance because it is linked to the highest production of testosterone, particularly in your first REM phase. Testosterone plays a critical role in muscle repair and growth. As an anabolic hormone, its primary role is to build muscle. For athletes that are training, this is a critical component of your training cycle. The point of training is to cause some muscle damage, which in turn stimulates muscle repair and growth. Without adequate testosterone production, the muscles can’t reach their potential.

Here are some ways that you can improve your sleep quality:

  • Limit screen time 30-60 minutes before bed
  • Don’t drink caffeine after noon
  • Exercise at least four hours before you go to bed
  • Go to sleep at a consistent time each night
  • Sleep in a dark, quiet room
  • Establish a nighttime routine

Cortisol is another hormone that plays a significant role in not only your sleep, but also your performance. Cortisol, the “stress hormone,” can prevent us from transitioning from light sleep to deep sleep to REM sleep. Additionally, cortisol can significantly impact our performance in three ways.

First, cortisol levels typically peak when we wake up. If cortisol levels are chronically high, the body can have a difficult time shutting down and reaching deeper levels of sleep. This can not only prevent us from falling asleep, but also from reaching REM sleep. Poor motor functions and feelings of fatigue can impact training.

Next, if REM sleep is not achieved or is reached less often, testosterone production will suffer. As discussed above, lower testosterone production will impact the ability to repair and grow muscle. Lack of sleep will also cause an increase in cortisol, compounding the effects.

Cortisol acts as the opposite of testosterone.

Cortisol is a catabolic hormone, meaning that it breaks things down, primarily muscle and fat. Cortisol’s main role in the body is to break down muscle and fat and convert it into glucose, our body’s primary fuel source. In doing so, the body produces vital energy to hopefully escape whatever has caused the spike in cortisol. Evolutionarily, this was essential for outrunning a predator. Today, however, our body responds in the same way to general stressors of life like a fight with a partner, traffic, or a tight deadline.

Understandably, having a high level of cortisol is not ideal for athletes since it will go to work breaking down the muscle you’ve struggled to build through training, as well as interfering with testosterone’s ability to grow that muscle. Managing your cortisol level is imperative for healthy sleep and performance.

Here are some ways you can manage your cortisol level:

  • Practice 5 or more minutes of meditation per day
  • Incorporate yoga once per week
  • Find a creative outlet like journaling, painting, or playing an instrument
  • Acknowledge when thoughts aren’t productive and choose to avoid them
  • Get at least 7-9 hours of sleep
  • Eat enough calories to support your training

Many factors can impact the quality of sleep. Fortunately, many of them are firmly within our control.

Choose to focus on 1-2 changes each week to improve your sleep hygiene and improve your performance. Add one additional component each week.

Just because a better night’s sleep doesn’t have a significant cost investment doesn’t mean that it won’t have a significant impact on your performance.

Ashley Reaver is the founder of Ashley Reaver Nutrition, a private practice that offers nutritional services. She also created  My Weekly Eats, a health/wellness blog-social media brand that focuses on easy, make-ahead recipes and meal plans.

Ashley’s knowledge areas and counseling specialties include sports nutrition, weight loss, cooking classes, meal planning, and intuitive eating principles. She holds a Bachelor of Science in Nutritional Science from Cornell University. In addition, she completed her dietetic internship at California Polytechnic University. Afterwards, she earned her Master of Science in Nutrition Science and Policy from Tufts University.

Ashley is also a Certified Sports Specialist Dietitian.



All bloggers receive a small compensation for their contributions.

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