Middle-aged, women they say disruptions are to be expected. Sleep may become lighter, nights may be warmer, and energy may be harder to come by. Hormones change and the body adapts. But for a huge number of women, something else also happens: While they sleep, their airways collapse dozens of times an hour.
Obstructive sleep apnea (OSA), once viewed as a disorder primarily affecting older, heavier men, is increasingly recognized as a much more sophisticated and often undetectable condition, particularly in perimenopausal and menopausal women.
OSA occurs when the upper airway narrows or collapses during sleep, oxygen levels drop, and the brain briefly stimulates the body to breathe again. For years, it was viewed as a single disorder with a familiar face. Researchers now understand it to be much more sophisticated: a heterogeneous condition shaped by different biological mechanisms and expressed through different symptom patterns. However, the older, larger male archetype still shapes who gets diagnosed and who doesn’t.
Recent performance in The Lancet Respiratory Medicine suggests that the problem is much bigger – and affects women more – than previously thought. Scientists estimate that by 2050, nearly 77 million American adults ages 30 to 69 will have OSA, a 65% relative augment in prevalence among women to approximately 30.4 million, compared with a 19% relative augment among men. This augment reflects an aging population and rising obesity, but hopefully also something more fundamental: better detection.
Carlos Nunez, chief medical officer at ResMed, who supported the analysis, explains that although more than a billion people worldwide suffer from sleep apnea, in some countries as many as 90 percent are undiagnosed and untreated. “It’s a condition in which people often live anonymously. Most people don’t realize they suffer from it because when it happens, they sleep,” he says.
Although OSA can occur at any age – even in children – the risk increases because decreasing muscle tone makes it complex to keep the airway open during sleep. However, for women, menopause is a crucial moment. Research shows that postmenopausal women are at a much higher risk of developing OSA. One analysis from the US Health Survey found that postmenopausal women were about 57 percent more likely to have symptoms of sleep apnea than premenopausal women, even after taking body weight into account.
“Women are hormonally protected by estrogen until menopause,” says Marie-Pierre St-Onge, director of the Center of Excellence for Sleep & Circadian Research at Columbia University. He explains that around this time, the distribution of fat shifts towards the neck and upper body, increasing pressure on the airway.
Tests suggests that estrogen and progesterone have a protective effect on the regulation of breathing and the activity of the muscles of the upper respiratory tract. As levels of these hormones decline after menopause, their effect wanes, which may contribute to a greater likelihood of your airway collapsing during sleep.
Rashmi Nisha Aurora, professor of medicine and director of the Women’s Sleep Medicine Initiatives at Recent York University’s Grossman School of Medicine, describes estrogen as a major antioxidant defense. As it declines, protection against oxidative stress weakens, just as OSA itself exposes the body to repeated oxygen drops and inflammatory stress. The result, she says, is a physiological “double effect,” increasing the workload on the heart and metabolic system.
Aurora notes that pregnancy is another time when hormonal fluctuations temporarily augment susceptibility to OSA.
The paradox is that menopause is also the time when OSA is most easily misinterpreted, because women’s symptoms – which may differ from men’s – include night sweats, fatigue and restless sleep, which overlap with menopause itself. “That’s where it really gets overlooked,” Aurora says. “Part of the problem was identifying and investigating cases.”
The checklists that doctors rely on – noisy snoring, unwitnessed pauses in breathing, excessive daytime sleepiness – have largely been developed and validated in male or mixed cohorts. Many of the most commonly used tools to measure hypersomnia, including the Epworth Sleepiness Scale, have not been validated in women of different age groups. Symptoms that often trigger a referral for CPAP, such as excessive daytime sleepiness, may be described or experienced differently by women.