What does exercising right before bed do to my sleep?

Vigorous exercise in the evening, where your workout ends less than 4 hours before bedtime, is associated with poorer sleep. This was shown in a large-scale study of nearly 15,000 people covering more than 4 million nights: you fall asleep later, sleep for shorter periods, sleep less deeply, and your heart rate during the night stays elevated. The more intense the effort and the later the time, the greater the effect.

If your workout ends at least 4 hours before bedtime, there is no measurable negative effect on your sleep, no matter how hard you have trained. This gives you a clear rule of thumb: preferably schedule intense workouts before 7 p.m. if you want to be asleep by 11 p.m.

Exercising regularly at a suitable time is actually beneficial for your sleep. Multiple studies show that strength training, aerobic training (such as running or cycling), and yoga and tai chi all significantly improve sleep quality compared with not exercising at all. In older adults with insomnia, strength training appears to be the most effective, outperforming aerobic training alone or combined training.

Similar findings apply to specific groups. In women who are going through or have been through menopause, movement-based exercises such as yoga, tai chi and Pilates noticeably improved sleep quality, although there was considerable variation between individual studies. In middle-aged and older adults with sleep problems, twelve weeks of moderate aerobic training was already sufficient to produce a clear improvement.