The association between nocturnal hot flashes and sleep in breast cancer survivors.

This study examined the relationship between objectively measured nocturnal hot flashes and objectively measured sleep in breast cancer survivors with insomnia. Twenty-four women who had completed treatment for non-metastatic breast cancer participated. All were enrolled in a study of cognitive-behavioral treatment for chronic insomnia. Nocturnal hot flashes and sleep were measured by skin conductance and polysomnography, respectively. The 10-minute periods around hot flashes were found to have significantly more wake time, and more stage changes to lighter sleep, than other 10-minute periods during the night. Nights with hot flashes had a significantly higher percentage of wake time, a lower percentage of Stage 2 sleep, and a longer REM latency compared to nights without hot flashes. Overall, hot flashes were found to be associated with less efficient, more disrupted sleep. Nocturnal hot flashes, or their underlying mechanisms, should be considered as potential contributors to sleep disruption in women with breast cancer who report poor sleep.