4 Ways Poor Sleep Can Sabotage Fitness Goals

4 Ways Poor Sleep Can Sabotage Fitness Goals


by Shane Creado, MD

If you work with people who are trying to lose weight, build lean muscle mass, or improve athletic performance, it’s critical to talk to them about getting adequate rest. Let’s look at just some of the many ways sleep can impact the ability to reach fitness goals.

1. Sleep deprivation tanks testosterone levels.

Anyone who is trying to build more muscle or get leaner needs healthy testosterone levels. Testosterone is an anabolic hormone that promotes muscle growth and strength in both men and women. It also plays a role in fat loss and preventing fat gain. For example, research shows that the testosterone levels of obese men are about 30% lower than those in men at a healthy weight.

Lack of sleep lowers testosterone levels. In a trial with healthy young men, sleeping just 5 hours a night for a week caused testosterone levels to decrease by 10-15%. Sleeping less means less testosterone, which results in less lean muscle and more fat.

2. Lack of deep sleep decreases growth hormone.

Deep sleep coincides with the release of growth hormone. Many of the body’s cells also show increased production and reduced breakdown of proteins during deep sleep. Since proteins are the building blocks needed for muscle growth, repair of damaged tissue, and bone-building, deep sleep is critical for athletic achievement and recovery from tough workouts. It is also vital for healthy growth and muscle development in children and adolescent athletes.

Unfortunately, 69% of high school students in the U.S. do not get adequate sleep. Because of this, children and teen athletes may potentially suffer from stunted growth as well as other direct impacts on sports performance.

Additionally, when a child or adolescent has growth hormone deficiencies, concentration and reaction times can be affected (frontal lobes), math and art skills can suffer (parietal lobes), and memory centers (temporal lobes) take a big hit.

3. Sleepless nights spike stress hormones.

Physical activity increases the production of cortisol and testosterone. Cortisol plays a central role in the body’s response to physical activity and the regulation of the immune system. The balance and timing of the release of anabolic (testosterone) and catabolic (cortisol) hormones are considered essential to muscle adaptation, especially muscle growth.

Sleep deprivation can lead to more cortisol production, which can worsen stress, accelerate muscle breakdown, and further contribute to insomnia/excessive wakefulness, setting up a bad feedback loop.

4. Poor sleep can make you fat.

If hormones are the gatekeepers of your cells, then sleep deprivation is a Trojan horse. Short sleep duration is one of the strongest risk factors for obesity. In one massive review study, children and adults with short sleep duration were 89% and 55% more likely to become obese, respectively.

Possible mechanisms include:

  • Sleep deprivation can be caused by, as well as result in, increased cortisol and adrenaline, which can break down muscle and store fat.
  • Sleep deprivation, as explained above, leads to less testosterone, less growth hormone, and more muscle breakdown.
  • Sleep deprivation interferes with the production of appetite hormones. Leptin is a hormone that suppresses appetite, while ghrelin stimulates it. Lack of sleep has been shown to reduce leptin and increase ghrelin, which increases appetite and calorie intake, resulting in added fat stores.

To quantify this, approximately 4 hours of sleep deprivation results in a perceived deficit of 900 calories, which means your body will think you need 900 more calories for every 4 hours of sleep you lose. Eating an extra 900 calories can quickly add up to excess fat on the body.

Many of the patients I see tell me that they rarely lose 4 hours of sleep in a week. But I explain to them that the brain needs 9 hours of sleep a night, so even if someone is getting what they think is a “healthy” 7 hours of sleep a night, at the end of the week, it adds up to 14 hours of sleep deprivation. When you help patients or clients think about it this way, they begin to see how their lack of sleep may be holding them back from reaching their fitness goals.

It’s our job as clinicians to help people who are trying to lose weight or trying to build muscle understand that getting quality sleep is just as crucial to their fitness goals as nutrition and exercise.

About the Author: Shane Creado, MD, Amen Clinics Chicago 

Dr. Shane Creado is a board-certified sleep specialist, who works not only on the treatment of sleep disorders but also on perfecting and optimizing sleep. He is the host of the Overcoming Insomnia course, which teaches the best evidence-based strategies to improve sleep. Dr. Creado is also the author of Peak Sleep Performance: The Cutting-Edge Sleep Science That Will Guarantee A Competitive Advantage, available on Amazon.

This book is primarily geared toward coaches, trainers, and elite athletes, but this step-by-step guide to sleep optimization can also be beneficial for anybody who wants to boost their brain health and productivity. For updates about the book, free sleep tips, as well as special offers, follow @peaksleepperformance on Instagram.



  1. Can someone call me back, as I need to speak with someone due to my depression. I think I may need some assistance to get though this time. Thanks,

    Comment by Ginger Schmidt — July 27, 2020 @ 6:36 AM

  2. Hello Ginger, thank you for reaching out. We’d be happy to contact you, we look forward to speaking with you!

    Comment by Amen Clinics — July 27, 2020 @ 4:55 PM

  3. I absolutely believe this. I’m a 36 year old life-long insomniac who has also been struggling with my weight since early childhood. I have experienced a number of issues which science has linked to chronic poor sleep as well as other related things, such as memory and a decline in cognitive function since my 20s. I have been on a number of medications for insomnia over the years as well, having only one that ever helped. Unfortunately, it stopped working after awhile. I do a number of things to improve my sleep, such as meditation and breathing exercises, yet I still have a lot of difficulty falling asleep and wake up several times during the night. I also suffer from chronic nightmares and stress dreams. I have been diagnosed with a number of physical and mental illnesses and to be honest, finding good quality scientific information on things like nutrition, weight loss and sleep is very frustrating. I appreciate the article, but I would appreciate one that suggested some possible solutions as to how to improve sleep, aside from all the general well-known ideas, much more.

    Comment by Storm M Dee — July 28, 2020 @ 1:24 PM

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