Doing this specific type of exercise twice a week could help you sleep better, study shows — but there's a catch

A woman lays in bed, smiling with her eyes closed, while holding her pillow.

If you experience issues with your sleep, such as insomnia, regular awakenings or other sleep disorders, you may have considered exercise as a tool to help (and if you haven't, there's plenty of evidence that it can improve sleep).

But what kind of physical activity is best for sleep? And how much of it you should be doing?