A new UCLA study has found that sleep apnea is more harmful to women than men. The study, conducted by the UCLA School of Nursing, reported that shows that the body’s autonomic responses—the involuntary nerve responses that affect functions such as blood pressure, heart rate and sweating—are weaker in individuals with obstructive sleep apnea but are even more diminished in women. The findings were published on October 23 in the journal PLOS ONE.
Obstructive sleep apnea affects more that 20 million adults in the U.S. and is associated with a number of serious health consequences and early death. It occurs when a person’s breathing is repeatedly interrupted during sleep, sometimes hundreds of times. Each time, the oxygen level in the blood drops, eventually resulting in damage to many cells in the body. Women are much less likely to be diagnosed than men. “We now know that sleep apnea is a precursor to bigger health issues,” explained lead researcher Paul Macey, PhD. He added, “And for women in particular, the results could be deadly.”
The study group comprised men and women, both those with and those without obstructive sleep apnea. Their heart-rate responses were measured during three physical tasks: (1) The Valsalva maneuver in which the subjects breathe out hard while the mouth is closed; (2) A hand-grip challenge in which the subjects squeeze hard with their hand; and (3) A cold pressor challenge in which a subject’s right foot is put in almost-freezing cold water for a minute. In all three tests, changes to the normal heart rate were lower and delayed in patients with obstructive sleep apnea, compared with healthy controls. Furthermore, the difference was more pronounced in women.
Dr. Macey explained, “The heart-rate results for these tests show that the impact of sleep apnea, while bad in men, is more severe in women. This may mean that women are more likely to develop symptoms of heart disease, as well as other consequences of poor adaptation to daily physical tasks. Early detection and treatment may be needed to protect against damage to the brain and other organs.”
The investigators next plan to determine whether the autonomic responses improve with treatments such as continuous positive airway pressure (CPAP); this is the standard sleep apnea therapy, in which a machine is used to help an individual breathe easier during sleep. In addition, they also plan to evaluate other forms of treatment for sleep apnea.