Hot Flashes Disturb First Four Hours of Sleep

Finding may explain conflicting results on menopause-related sleep disturbances

FRIDAY, Sept. 30 (HealthDay News) -- Sleep disturbances caused by hot flashes are more likely to occur during the first four hours of sleep in peri- and postmenopausal women, researchers reported this week at the North American Menopause Society's annual meeting in San Diego.

Robert R. Freedman, Ph.D., of Wayne State University School of Medicine in Detroit, and colleagues studied 12 symptomatic and eight asymptomatic postmenopausal women and 11 cycling women, aged 46 to 51.

There were no differences between the groups in sleep measures. The study was repeated under cold (18 degrees Celsius) neutral (23 degrees Celsius) and warm (30 degrees Celsius) conditions. REM sleep, which is more common in the second half of the night, can suppress thermoregulatory responses, including hot flashes.

Women tended to have their sleep disturbed by hot flashes in the first half of the night, but not the second. Under cooler conditions, hot flashes were reduced in the first half of the night. The finding may explain conflicting results of previous studies, the authors write. "Treatment of hot flash-induced sleep disturbance should be directed towards the first four hours of sleep."

Abstract (P.11)

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