Sleep (SLP) is essential for good health and men's health. Previous studies have found that sleep quality is essential for a healthy weight (i.e., reduced obesity), libido, vigor and sex drive, bone density, reproductive and androgen function (i.e., SLP loss can result in reduced blood testosterone levels), and an overall healthy lifestyle.
Sleep and Testosterone Study Key Points
- Chronic sleep loss is associated with low testosterone (i.e., hypogonadism) and testosterone deficiency.
- A study found that people who slept less were associated with smaller testicle sizes.
- More studies must be conducted to confirm sleep and testicular size. There are very few studies to confirm this study.
Sleep Deprivation & Sleep Apnea Destroys Health
Previous studies have found that sleep quality is essential for a healthy weight (i.e., reduced obesity), libido, vigor and sex drive, bone density, reproductive and androgen function (i.e., SLP loss can result in reduced blood testosterone levels), and an overall healthy lifestyle.
Unfortunately, millions of Americans don’t get the necessary 8 hours of sleep and have poor sleep habits. More specifically, 32% of American adults have SLP insufficiency (<7 hours per night), 10% of Americans work evenings and nights, and up to an additional 6% of workers have SLP disturbances. (Okoro et al., 2020) Caffeine has numerous benefits for exercise performance but can result in poor sleep. Caffeine has a long half-life, which means it can stay in the blood for long periods. This can result in sleep problems and disruption in deep sleep (i.e., less rapid eye movement REM) and disrupt circadian rhythm if consumed too late in the day.
Numerous articles have been written on Evidence Based Muscle about getting adequate SLP for increased anabolic hormone levels, muscle gains, and weight loss. Lack of sleep can result in decreased productivity, lower levels of testosterone, and an increased risk of developing chronic diseases (i.e., high blood pressure). Not getting enough sleep can significantly impact our overall health and well-being. Not getting sleep also results in low levels of testosterone and erectile dysfunction.
Sleep and Testosterone Production
SLP plays an important role in testosterone production in men. SLP disruption and obstructive sleep apnea are associated with low testosterone levels. After just one week of insufficient SLP, daytime testosterone levels decreased by 10% to 15%. Moreover, the decline in testosterone levels was linked to a decrease in mood and vigor scores. (Leproult & Van Cauter, 2011)
Insomnia, REM Sleep, and Testosterone Production
Plasma testosterone levels begin to increase with the onset of SLP, and in young men, testosterone levels peak at the first REM SLP episode and remain at that level until waking. (Wittert, 2014) Testosterone production depends on SLP, generally reaching the peak during the first 3 hours of uninterrupted SLP, and at least in young men, at about the time of the first REM episode.
Insomnia, REM Sleep, and Testosterone Production
Plasma testosterone levels begin to increase with the onset of SLP, and in young men, peak at the first REM SLP episode and remain at that level until waking. (Wittert, 2014) Testosterone production depends on SLP, generally reaching the peak during the first 3 hours of uninterrupted SLP, and at least in young men, at about the time of the first REM episode.
Is Sleep and Muscle Growth Related?
As we have learned, SLP plays an important role in testosterone production, which is crucial for overall male health. However, not just testosterone levels are affected by lack of SLP. It turns out that hypertrophy also suffers when we do not get enough shut-eye.
During SLP, our bodies repair and regenerate muscle tissue, making it essential for lean mass gains. Without enough SLP, our muscles may not have the opportunity to fully recover from exercise, leading to slower gains in strength and size. Previous studies have discovered that those who slept less possessed less mass. (Buchmann et al., 2016)
The Surprising Link Between Sleep and Testicle Size
If a person is dieting, a larger loss of lean muscle mass has been reported in subjects who slept 5.5 hours a night compared to those sleeping 8.5 hours a night. (Nedeltcheva et al., 2010) One theory explaining why insufficient SLP can cause loss of lean muscle is a previous study that found that 72 hours of SLP deprivation led to increased cortisol and protein breakdown. (Kant et al., 1984)
Testosterone replacement therapy (TRT) is a common treatment option for men with low testosterone levels and symptoms of hypogonadism, which can help restore energy levels and regain masculine qualities lost due to low testosterone production. However, it is essential to note that TRT has various risks, including worsening sleep apnea, a potentially serious sleep disorder.
How Sleep Affects Testicle Size
Recent research has also discovered the relationship between SLP and reproductive health. A study by (Zhang et al., 2018) found a correlation between SLP duration and the testicles testis size in healthy young men, suggesting that SLP may significantly impact male reproductive health.
Sleep and Testicle Size
The study consisted of 92 healthy young men aged 22 to 45 (i.e., the average age of 32) years to investigate the relationship between SLP duration and testis size. Participants were recruited from a university population. The study excluded individuals with any chronic medical conditions, SLP disorders, or those taking medications that could affect SLP or hormonal function.
The researchers asked the participants to maintain an SLP diary and wear an actigraphy watch for two weeks to objectively measure their SLP duration. The doctors assessed testis size using an orchidometer. An orchidometer consists of a string of twelve numbered wooden or plastic beads of increasing size ranging from about 1 to 25 milliliters. Each bead has a label indicating its volume, helping doctors determine the testicle’s size.
The study found a significant association between SLP duration and testis size. Participants with shorter SLP durations had smaller testis volumes than those with longer ones. Additionally, the study found that SLP duration was positively correlated with testosterone levels, suggesting a potential mechanism linking SLP duration and testis size. The results showed that men who slept for less than 6.5 hours per night had significantly smaller testis sizes than those who slept for 7-7.5 hours per night.
The authors hypothesize that the smaller testis size may result from the lower testosterone levels in participants with shorter SLP durations. Testosterone is an essential hormone for male reproductive health, playing a vital role in sperm production and overall sexual function.
While the study does not establish causality, it raises important questions about the potential impact of SLP on male reproductive health. It is well-known that SLP deprivation can lead to hormonal imbalances, negatively affecting various health aspects. In the context of male reproductive health, SLP may be particularly important for maintaining optimal testis size and function.
Other Factors That Affect Testicle Size
As we have seen, sleep and testosterone production is directly linked to men’s health and possibly testicle size. However, several other factors can impact testicle size as well.
- Age is one of the most significant factors, with testicles typically decreasing in size as men get older.
- Hormones also play a crucial role, with testosterone and other hormones affecting testicle size.
- Genetics can influence testicle size, while certain health conditions and lifestyle habits can also have an impact.
- Maintaining a healthy diet is essential for optimal testicular health. A balanced diet rich in whole foods can provide the necessary nutrients to support healthy testicular function.
- Regular exercise and physical activity can have numerous benefits for overall health.
Buchmann, N., Spira, D., Norman, K., Demuth, I., Eckardt, R., & Steinhagen-Thiessen, E. (2016). Sleep, Muscle Mass and Muscle Function in Older People. Dtsch Arztebl Int, 113(15), 253-260. https://doi.org/10.3238/arztebl.2016.0253
Cote, K. A., McCormick, C. M., Geniole, S. N., Renn, R. P., & MacAulay, S. D. (2013). Sleep deprivation lowers reactive aggression and testosterone in men. Biological Psychology, 92, 249-256. https://doi.org/10.1016/j.biopsycho.2012.09.011
Hanafy H. M. (2007). Testosterone therapy and obstructive sleep apnea: is there a real connection?. The journal of sexual medicine, 4(5), 1241–1246. https://doi.org/10.1111/j.1743-6109.2007.00553.x
Kant, G. J., Genser, S. G., Thorne, D. R., Pfalser, H. L., & Mougey, E. H. (1984). Effects of 72 Hour Sleep Deprivation on Urinary Cortisol and Indices of Metabolism. Sleep, 7(2), 142-146. https://doi.org/10.1093/sleep/7.2.142
Leproult, R., & Van Cauter, E. (2011). Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA, 305(21), 2173-2174. https://doi.org/10.1001/jama.2011.710
Nedeltcheva, A. V., Kilkus, J. M., Imperial, J., Schoeller, D. A., & Penev, P. D. (2010). Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med, 153(7), 435-441. https://doi.org/10.7326/0003-4819-153-7-201010050-00006
Okoro, C. A., Courtney-Long, E., Cyrus, A. C., Zhao, G., & Wheaton, A. G. (2020). Self-reported short sleep duration among US adults by disability status and functional disability type: Results from the 2016 Behavioral Risk Factor Surveillance System. Disabil Health J, 13(3), 100887. https://doi.org/10.1016/j.dhjo.2020.100887
Wittert, G. (2014). The relationship between sleep disorders and testosterone in men. Asian Journal of Andrology, 16(2), 262-265. https://doi.org/10.4103/1008-682x.122586
Zhang, W., Piotrowska, K., Chavoshan, B., Wallace, J., & Liu, P. Y. (2018). Sleep Duration Is Associated With Testis Size in Healthy Young Men. Journal of Clinical Sleep Medicine, 14(10), 1757-1764. https://doi.org/doi:10.5664/jcsm.7390