Why Do Men Sleep Better Than Women?
Insomnia affects nearly 15% of adults in the United States, with women being 41% more likely to experience issues with sleep. Could it be due to the fact that men are three times less likely to go to the doctor than women? Perhaps, but that’s a whole different conversation. Research suggests that it could be due to the levels of sex hormones circulating in the body.
Differences in Sleep Experience
Qualitative research has found that while women do report sleeping longer, they also report having more interrupted sleep than men.
A poll by the National Sleep Foundation determined women report experiencing insomnia a few times a week, ranging from trouble falling asleep initially to waking up more often throughout the night and having difficulty returning to sleep once awake. However, men are not completely off the hook.
Males reported instances of snoring and experiencing pauses in breathing during their slumber more frequently than their female counterparts. They also reported needing more than the minimum required amount of sleep in order to feel refreshed and ready for the day ahead.
Perception of sleep quality may be influenced by underlying conditions such as anxiety, depression, and affective disorders, which all potentially increase the frequency of insomnia.
Sex Hormonal Influence
Brain function, chemistry, and even composition are influenced by biological gender. Therefore, it should not be surprising to find differences between males and females in circadian biology. Exposure to sex steroids (estrogen, progesterone, and testosterone) during development mediates the bulk of sex differences observed in the nervous system, including functional differentiation. Generally, these differences become noticeable when sex hormones begin performing their distinguished roles during puberty and across adulthood.
Earlier research in this area proposed a significant influence of ovarian steroids in females on sleep-wake cycles and, though not as profound, an influence of testicular steroids in males. Later studies confirmed that there is a relationship between sleep and testosterone levels, although it is more difficult to identify in men.
Ovarian Sex Steroids and Sleep
In addition to age-related changes, physiological changes in a woman’s body could potentially cause poor sleep quality. These changes include hormonal fluctuations during the menstrual cycle, pregnancy, postpartum, and menopause.
Oral contraceptive use, which alters the levels of sex hormones circulating, could also have an influence on circadian rhythm.
There have been strong associations reported between insomnia and third trimester pregnancy, menopause, and the late-luteal phase of the menstrual cycle. Imbalances in estrogen and progesterone levels are suggested causes of shifts in sleep patterns in women. Because progesterone’s metabolite, allopregnenolone, is a GABA agonist, it promotes GABA function. GABA is an important inhibitory neurotransmitter, necessary for supporting sleep and mood.
Estrogen, Estradiol (E2), and Serotonin
Estrogen in the form of Estradiol (E2) has been shown to increase the number of serotonin receptors in the brain. Serotonin is also an inhibitory neurotransmitter involved in sleep and mood regulation. As women age, sex hormone levels are constantly declining. This indicates that the decline in sex hormones with age may not be the only mechanism at work for poorer sleep in older women.
With all of this instability in ovarian sex steroids throughout a woman’s lifetime, it is no wonder women report sleep disturbances more frequently than men.
Testicular Sex Steroids and Sleep
While information is limited on testosterone’s effects on sleep, the evidence is significant. Testosterone levels may be reduced by defects in circadian rhythm, sleep quality, and duration of sleep in men over 65. Lower testosterone levels have been linked to reduced sleep efficiency, more awakenings during the night, and less deep sleep, known as slow-wave sleep.
Testosterone is a Serotonin Agonist
It is also known that testosterone acts as a serotonin agonist, meaning that more testosterone is equivalent to more serotonin function. As discussed earlier, serotonin has activity in modulating mood and sleep patterns. However, research found that increased levels of testosterone, induced by testosterone administration, are associated with reduced sleep times, increased number of awakenings, and more occurrences of insomnia. Thus, it can be concluded that an appropriate balance of testosterone is crucial for optimal circadian pattern.
Potential Treatment for Insomnia via Hormone Replacement Therapy
Hormone replacement therapy (HRT) is being studied as an option for insomnia treatment. However, research has been more focused on estrogen supplementation for menopausal women struggling with sleep difficulties, as insomnia seems to be more frequent in this population.
Hot Flashes and Hypothalamic Activity
Hot flashes have taken a huge portion of the blame for sleep issues in menopausal women. Experts believe that hypothalamic activity is involved. When estrogen levels decrease in menopausal women, the hypothalamus, which controls body temperature, perceives an increase in body heat.
This perception causes the hypothalamus to release hormones to lower body heat, which consequently causes an adrenaline response that allows more blood to flow.
This adrenaline rush prompts the body’s natural remedy to an increased body temperature – what we call sweating.
Hormone Replacement Therapy (HRT) as a Treatment for Insomnia in Menopausal Women
Based on studies, the use of estrogen supplementation to reduce hot flashes could reduce the implications placed on sleep by this adrenaline rush. Though this seems like a promising treatment for women experiencing insomnia due to menopause, HRT is recommended in the lowest possible dose and for the shortest feasible time due to increased risk of breast cancer and cardiovascular disorders, based on WHI data.
Low-dose birth control pills have also been suggested as an alternative to help in stabilizing estrogen fluctuations during this menopausal period.
It is evident that sex hormones play an important role in circadian rhythm and sleep, in synergy with neurotransmitters and brain activity. With the proper balance, symptoms of insomnia and poor sleep can be better managed, leading to an overall improvement in health. Are you getting enough sleep?
Cabeca, A. (2010). Balancing the HPA-T axis and Managing Menopause Symptoms [Audio Lecture]. Retrieved from Sanesco International Inc.: http://www.sanescohealth.com/?post_type=portfolio&p=6097
Krucik, G. (24 July 2014). What causes hot flashes? 11 possible conditions. Retrieved from: http://www.healthline.com/symptom/hot-flashes
Mong JA, Baker FC, Mahoney MM, Paul KN, Schwartz MD, Semba K, & Silver, R. (9 November 2011). Sleep, Rhythms, and the Endocrine Brain: Influence of Sex and Gonadal Hormones. Retrieved from: http://www.jneurosci.org/content/31/45/16107.full
News Medical. (9 June 2011). National survey finds women more likely to see doctor on regular basis than men. Retrieved from: http://www.news-medical.net/news/20110609/National-survey-finds-women-more-likely-to-see-doctor-on-regular-basis-than-men.aspx
Orff HJ, Meliska CJ, Martinez LF, & Parry, BL. (26 June 2014). The influences of sex and gonadal hormones on sleep disorders. Retrieved from: https://www.dovepress.com/the-influence-of-sex-and-gonadal-hormones-on-sleep-disorders-peer-reviewed-article-CPT
Walseleben, J. (2016). Menopause and Insomnia. Retrieved from: http://sleepfoundation.org/ask-the-expert/menopause-and-insomnia
James, L. The Importance of Sleep [Infographic] [Digital image]. Retrieved March 1, 2016, from http://lucasjamespersonaltraining.com/importance-sleep-infographic/4584/