Today's Moment of Science concerns the relationship between estrogen and breathing. Actually, today's Moment of Science is also about a disorder called sleep apnea. That's because research on sleep apnea is how the relationship between estrogen and breathing was discovered.
First, sleep apnea is a disorder in which air is obstructed to some degree from entering a person's body while he or she sleeps. Usually, this is because the tongue or other muscles relax and block the air passage. The effects include heavy snoring, frequent awakenings, and brief periods of one's breathing stopping. Sound dangerous? It is.
The fact that the majority of sleep apnea sufferers are middle-aged men led researchers to investigate the influences age and gender have on the disorder. When they found that female rats at various ages consistently responded to withheld oxygen by taking in deeper and longer breaths, researchers began looking at estrogen, the female super hormone. Estrogen revs up the chemical serotonin, which works to transmit nerve signals; thus, leading to faster communication between different parts of the body. In other words, estrogen may be responsible for the female rat's heightened response to oxygen deprivation.
This may explain why middle-aged women suffer less from sleep apnea than middle-aged men. That is, women typically have about twice as much estrogen as men. In tune with this theory is that later when women hit menopause, and estrogen levels decline, their susceptibility to sleep apnea rises--unless that is, they get on hormone replacement therapy, in which case their estrogen levels remain high, and they breathe well throughout the night.