Sleep quality improves with exercise, but it could take months

A good night’s sleep has an immediate effect on encouraging exercise the next day, but it could take months before exercise improves your sleep quality, a new study has found.

Researchers from Northwestern University’s Feinberg School of Medicine in Chicago examined the short-term and long-term relationship between sleep and exercise among 11 women with insomnia. In the short term, results suggested “sleep influences next-day exercise rather than exercise influencing sleep … These results suggest that improving sleep may encourage exercise participation.”

In the longer-term, however, regular exercise sessions of 30 minutes of cardio, three to four times per week, improved sleep quality over the 16-week study, which was published in the Journal of Clinical Sleep Medicine. Those who exercised also reported improvements in their mood and general quality of life.

But the researchers found no improvements in sleep related to exercise on a day-to-day basis, only through the cumulative effect of several weeks of regular physical activity. Even two months into the study, the subjects who were prescribed exercise saw no measurable gains in sleep quality. After the full 16 weeks, however, the benefits were significant.

“Just keep in mind that the effect may happen gradually, not all at once.” sleep doctor Michael J. Breus wrote in The Huffington Post. “This is how we think of exercise as applied to weight loss – and we may need to think of exercise in relation to sleep the same way.”