On the other hand, training may also affect sleep. It's probably a good idea to keep your workouts brief, as some research indicates that long-duration, moderate to intense exercise can cause a decrease in nighttime secretion of testosterone and GH and a simultaneous rise in cortisol. Also, working out every other day or taking at least a couple of days off every week from working out may give your body and brain adequate amounts of non-REM and REM sleep, ensuring that both function optimally.

Sports researchers seem to agree that the more physical or mental energy spent during the day, the greater the need for quality, continuous, multiple-stage sleep. To ensure a healthful night's sleep, try these six tips:

• Plan on a daily transition from stimulating activities to less-active, relaxing pursuits up to three hours prior to sleep—such as reading, listening to music, or taking a casual walk.
• Take supplements containing a 2:1 ratio of calcium to magnesium, augmented with optimal intake of Vitamin B-complex micronutrients (especially B5 and B6).
• Avoid consumption of caffeine, alcohol, and foods rich in tyrosine or tyramine at least four hours before going to bed.
• Avoid stimulation from exercise, stress, and medications at least three hours prior to sleep.
• See if you can synchronize your sleep pattern with available sunlight by developing the habit of going to bed when the sun sets and walking near the time when it rises. While this is not always possible (especially in the winter), you can try to reinforce your basic sleep cycles by providing a dark, quiet environment for sleep.
• If you nap during the day, attempt to sleep for at least 30 to 60 minutes for optimal recuperation, rejuvenation, and muscle growth.