Exercise and Sleep: The Two-Hour Rule
In general, physical activity helps promote sleep; and of course, sleep is good for your health, too. But your timing can make a big difference when it comes to whether you'll enjoy a restful night's sleep or a restless one that actually does more harm than good.
When is the right (and wrong) time to exercise before turning in for the night? Researchers have discovered the answer, and the two-hour mark holds an important key.
An analysis of 15 previous studies, published in Sleep Medicine Reviews, examined exercise timing and its impact on sleep by evaluating timing on two levels: time of day (early evening or late evening) and hours between exercising and bedtime (fewer than two hours, approximately two hours or 2-4 hours). Researchers also analyzed variables such as fitness level (sedentary vs. active), exercise intensity and exercise duration. Here's what researchers determined based on the data:
Time of Day: Early-evening, high-intensity exercise is beneficial for sleep, promoting sleep onset and sleep duration.
Proximity to Bedtime: Exercising too close to bedtime (finishing exercising fewer than two hours before turning in) negatively impacts sleep, reducing sleep duration and increasing the time needed to fall asleep. By comparison, performing exercise that ends 2-4 hours before bedtime does not negatively impact either time to fall asleep or sleep duration.
Exercise Type and Intensity: High-intensity exercise (30-60 minutes) also positively impacts sleep, increasing sleep duration and reducing time necessary to fall asleep. (Cycling exercises were the most beneficial.)
If you're physically active, but struggle to fall asleep and/or stay asleep, your exercise routine may be to blame. Take these findings to heart and ensure you use exercise to promote restful, restorative sleep – not the opposite.