Many people say they want to exercise more, but in one survey 56% of adults said they were often just too tired to do it.

That epidemic of weariness isn't surprising. Almost 30% of adults get less than seven hours of sleep nightly. And lack of sleep makes it difficult to exercise well.

A study in the journal Physiology & Behavior found that tennis players who were short on sleep had up to 53 percent decreased serve accuracy. Another found that even one night of short sleep tanked the endurance of male runners and volleyball players.

According to the Mayo Clinic, one study found that that people who get 10 hours of sleep a night (more than the 7-8 we recommend) saw a 60% improvement in free throws and three-pointers compared to sleep-deprived basketball players.

If you have trouble accomplishing your physical activity goals, it may be time to improve your sleep habits:

• Head for bed at the same time every night.

• Make sure your room is cool, dark, and free of digital devices.

• Try 10 minutes of meditation nightly.

And ask your doctor about taking nonprescription sleep aids such as melatonin, a hormone produced in your pineal gland that signals to your body that it's time to sleep.

The Sleep Foundation recommends an adult dose of up to 5 mg daily. Dr. Mike is comfortable recommending up to 10 mg a day. Dr. Oz likes a lavender-scented infuser to promote sleep.