APSS: Moderate Evening Workout Improves Sleep in Insomnia

By Michael Smith
BALTIMORE,13 june 2008 -- Fifty minutes on a treadmill a few hours before bedtime helps patients with primary insomnia get to sleep, a researcher said here.In a controlled trial, those who did moderate aerobic exercise in the evenings fell asleep more quickly, woke less often, and increased their total sleep time, according to Giselle Passos, a doctoral student at the Federal University of Sao Paulo in Brazil.On the other hand, intense aerobic exercise and moderate strength training had no effect, Passos said at SLEEP 2008, the annual meeting of the Associated Professional Sleep Societies.
The results show that "there is a way to diminish the symptoms of insomnia without using medication," Passos said.
She added that the study "may contribute to increased quality of life in people with one of the most important kind of sleep disorders around the world."
People with insomnia are not usually advised to work out in the evening, because exercise has an arousing effect, commented Donna Arand, Ph.D., of the Kettering Hospital Sleep Disorders Center in Dayton, Ohio, who was not involved in the work.
Dr. Arand said it's well known that regular exercise has a "strong and good effect" on sleep quality, but insomnia experts have traditionally suggested it take place earlier in the day.
The advantage of the later hour is that many patients have busy days and the evening is the only time available for exercise. "This might be an option for them," Dr. Arand said.
She said the study adds support for the idea that exercise can be beneficial for those with primary insomnia, but added it needs to be replicated before it can become part of clinical practice.
Passos and colleagues enrolled 36 patients (including 28 women) with primary chronic insomnia and an average age of 44.4. Their sleep was evaluated using a sleep log and polysomnography in the sleep lab, after a night of laboratory adaptation.
The study included three experimental groups -- nine each taking moderate aerobic exercise, heavy aerobic exercise, moderate strength training -- as well as nine in a control group that did not exercise.
Those in the moderate-exercise group ran on the treadmill for 50 minutes at a pace that kept them below the first ventilatory threshold, regarded as a cutoff for moderate exercise.
Volunteers in the heavy-exercise group ran in three 10-minute bursts at the second ventilatory threshold (considered the level of intense exercise) with 10-minute breaks between. Those doing the strength training did exercises including shoulder presses, leg curls, and abdominal crunches for about 50 minutes.
The study found no significant changes in sleep for the heavy-exercise and strength-training groups. However, in the moderate group, the polysomnographic results showed:
A 54% reduction in sleep-onset latency -- from 41.5 minutes on average at baseline to 18.9 minutes after exercise -- which was significant at P<0.05.
A 36% decrease in time spent awake (also significant at P<0.05), from 146.7 minutes at baseline to 94 minutes after exercise.
A corresponding 21% increase in total sleep time, from 4.5 hours to 5.7 hours, which was significant at P<0.05.
An 18% increase in sleep efficiency, from 65% to 78.6%, also significant at P<0.05.
The sleep logs of the volunteers in the group also showed significant reductions (P<0.05) in total sleep time and sleep onset latency.
Dr. Arand noted that the researchers reported the effects of a single exercise session, rather than regular exercise.
The study was supported by the Associação Fundo de Incentivo à Psicofarmacologia, the Instituto do Sono, CEPE, CEMSA, FADA/UNIFESP, and FAPESP. Passos reported no conflicts.
Primary source: Associated Professional Sleep Societies meetingSource reference:Passos GS, et al "Physical exercise can improve sleep quality of insomniac patients?" APSS Meeting 2008; Abstract 737.