We commonly think of sleep apnea as being caused by obesity or structural problems. However, in women the transition into menopause can contribute to sleep apnea too. When estrogen is low, the brain fails to signal the palate and tongue to retain its tone during sleep. As a result they over relax and block the airway.
Female hormones play a role in sleep
The hormonal factors that contribute to sleep apnea are different in women than in men. In a study involving rats, researchers discovered that young male rats respond to normal episodes of hypoxia, or brief periods of oxygen deprivation, during sleep by increasing brain activity to take deeper and more frequent breaths. The older male rats did not have the same response.
But when scientists looked at female rats they discovered they reacted much differently to these hypoxic episodes. For instance, older female rats had a more positive response to oxygen deprivation than the older males. That response was even better during certain stages of the menstrual cycle in younger female rats, suggesting female hormones play a role in the response to hypoxia during sleep.
This could help explain why many women begin to experience sleep problems during perimenopause (pre-menopause) and menopause, when estrogen production begins to decline. Estrogen influences serotonin, an important brain chemical that transmits signals, including to the tongue and palate.
To test the theory, researchers removed the ovaries from female rats, inducing estrogen deficiency and menopause. They found less serotonin in the region of the brain controlling the tongue, which compromised the female rats' ability to respond to hypoxia during sleep. The lack of estrogen affected the brain function involved in breathing. This is consistent with evidence that shows the incidence of sleep apnea increases in women during midlife.
The rate of sleep apnea also increases in midlife for men, as declining testosterone results in worse brain coordination for sleep. This helps explain why many people start snoring as they get older.
Middle-aged men tend to snore more and experience the cessation of breathing during sleep. Middle-aged women, however, more commonly complain of insomnia, headache, fatigue, and irritability related to poor sleep. That estrogen deficiency promotes weight gain only compounds the problem of sleep apnea. Estrogen deficiency can also play a role in restless leg syndrome.
When estrogen begins to decline in women, the adrenal glands ideally take over the production of estrogen. The adrenal glands sit atop the kidneys and regulate the body's response to stress. Stressful lifestyles, processed foods, high sugar intake, and other factors of modern life leave many women entering midlife with poor adrenal function. As a result, estrogen levels may drop too low during perimenopause and menopause. Estrogen is vital for all aspects of a woman's health, including that of her brain, bones, immune system, and ability to sleep well. Adopting a whole foods diet free of processed carbohydrates and supporting adrenal health are some strategies to support estrogen levels.
For more information on supporting hormone levels and proper sleep, contact my office.