"Also, arousal and erection are activated by the parasympathetic nervous system, which controls digestion and reproduction, so too much stress will lessen these functions," he explained.
In the new study, researchers at the Walter Reed Military Medical Center in Bethesda, Md., followed 92 men, average age 46, who began using CPAP machines after being diagnosed with obstructive sleep apnea. While sleeping, patients wear masks connected to machines that send pressurized air into the throat to keep the airway open throughout the night.
The average participant was overweight. Forty-six percent reported erectile dysfunction, and 27 percent said they had diminished libido.
After six months, the researchers found that sexual function and satisfaction improved in the CPAP device users, and erectile dysfunction vanished in 41 percent of those who'd had erection issues.
Joyce Walsleben, a sleep medicine specialist and associate professor of medicine at the New York University School of Medicine, said the devices probably boost energy by improving sleep.
"It may well have to do with increased oxygen and the production of hormones and other neurotransmitters being reset," Walsleben said.
CPAP machines aren't for everyone. They're expensive -- prices range from several hundred dollars to more than $1,000 -- and some sleep apnea patients can't tolerate them. However, other treatments, such as surgery, exist for sleep apnea.
As for whether wearing a mask-and-hose getup ruins the mood in bed, Walsleben had this to say: "I can tell you that from people I know with the device, happy bed partners are much more interested in sex -- before or after sleep -- than those who are fighting over snoring or sleeping in separate rooms."
The study -- scheduled for presentation Wednesday at the Associated Professional Sleep Societies meeting in
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