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Short-term exercise may not help with insomnia

Exercise did not improve the total sleep time for patients with insomnia the following night, suggesting that only longer-term commitment to exercise will influence sleep, according to the results of a small Northwestern University study.

"If you have insomnia, you won't exercise yourself into sleep right away," study researcher Kelly Glazer Baron, PhD, clinical psychologist and director of the behavioral sleep program at Northwestern University Feinberg School of Medicine, said in a press release. "It's a long-term relationship. You have to keep at it and not get discouraged."

Baron and colleagues analyzed the effects of exercise on sleep in 11 women (mean age, 61.27 years) with insomnia who engaged in 30 minutes of aerobic exercise three times per week. The women reported on their sleep quality and wore wrist actigraph devices to measure total sleep time, sleep efficiency, waking after sleep onset and sleep fragmentation.

Total sleep time, sleep efficiency and sleep quality all improved throughout the 16-week study period (P<.05). However, daily exercise did not significantly improve sleep the corresponding night. Rather, longer sleep-onset latency shortened the duration of participants' exercise the following day (P<.05).

"This new study shows exercise and sleep affect each other in both directions: regular long-term exercise is good for sleep but poor sleep can also lead to less exercise," study researcher Phyllis Zee, MD, professor of neurology, said in the release. "So in the end, sleep still trumps everything as far as health is concerned," she said.

Disclosure: Zee reports financial relationships with Ferring Pharmaceuticals, Jazz Pharmaceuticals, Merck, Philips Respironics, Purdue, UCB and Vanda Pharmaceuticals.