Final answer:
Physical exercise generally improves sleep for most people and helps sleep disorders, such as insomnia. The optimum time to exercise for sleep benefits is four to eight hours before bedtime.
Step-by-step explanation:
Research shows that physical exercise generally improves sleep for most people and helps sleep disorders, such as insomnia. Exercise is the most recommended alternative to sleeping pills for people with insomnia. The optimum time to exercise for sleep benefits is four to eight hours before bedtime, although exercise at any time of day seems to be beneficial. However, heavy exercise undertaken shortly before bedtime may actually interfere with sleep.