Researchers at Northwestern University Feinberg School of Medicine studied 17 sedentary adults, all of whom suffered from chronic insomnia, to asses the effect of regular moderate aerobic exercise on sleep. Participants assigned to the aerobic physical activity group exercised for two 20-minute sessions four times per week or one 30-to-40-minute session four times per week, both for 16 weeks. Those in the non-physical activity group participated in non-physical recreational or educational activities for approximately 45 minutes three to five times per week for 16 weeks. Both groups received education about good sleep hygiene. Results showed that exercise improved participants’ self-reported sleep quality, so much so that their scores on the Pittsburgh Sleep Quality Index dropped by an average of 4.8 points – enough to be elevated from a diagnosis of “poor sleeper” to one of “good sleeper”. Those in the physical activity group also reported fewer depressive symptoms, more vitality and less daytime sleepiness. “This is relevant to a huge portion of the population,” said Phyllis Zee, M.D., director of the Sleep Disorders Center at Northwestern Medicine and senior author of the paper. “It is essential that we identify behavioral ways to improve sleep. Now we have promising results showing aerobic exercise is a simple strategy to help people sleep better and feel more vigorous. By improving a person’s sleep, you can improve their physical and mental health. Sleep is a barometer of health, like someone’s temperature. It should be the fifth vital sign.”
