While exercising at any time is healthier than parking your bum on the sofa, your workout schedule can make a difference in your performance. You have a circadian rhythm that plays a large part in energy levels, and learning how your body works will allow you to choose the best timing for your exercise sessions.

Peak Performance Time

According to the American Council on Exercise, the optimal time to exercise is in the late afternoon, when your body is warmest. This is also when your muscles are more flexible, your body is at its strongest and your blood pressure and heart rate are low. You will feel as though you're exerting less energy than at other times--even while performing identical activities--and you'll have faster reaction skills.

That said, if you already have an exercise schedule, you'll probably perform better by sticking to your current routine. Your body is an adaptable machine and changes to accommodate your activity. So if you run every day at noon, this will become your peak-performance hour. You can use this strategy when training for an athletic competition--train at the same time as the event to help give your best performance on the big day.

For Morning Birds

If you can't live without your morning workouts, take some extra time to warm up before building up the intensity. Your muscles are coldest in the morning, so you may be more prone to strains and other injuries.

Despite the body-temperature disadvantage, morning workouts can be helpful for people who have trouble sticking to an exercise schedule, according to WebMD. For some reason, people who work out in the morning are more likely to make the activity a long-term habit.

For Night Owls

If you get a second wind at night, it's usually fine to heed your natural calling and work out after dark. Problems can arise, however, if your activity affects your sleep schedule. Exercise elevates your heart rate and energizes your body, which can make it harder to drift off into slumberland.

If you start tossing and turning after late night exercise sessions, pull back your workout time to at least a few hours before your normal bedtime. Regular exercise should help you sleep better, not worse.

Frequency

How often you work out is far more important for your health than when you work out. To match guidelines set by the Centers for Disease Control and Prevention, get at least 150 minutes of moderate cardio activity per week. That works out to 30 minutes per day, five days per week although you can break it up however you please as long as each exercise period lasts at least 10 minutes (shorter sessions simply don't provide the same cardiovascular benefits).

You also need strength training two to three times weekly. Weightlifting, doing crunches or taking Pilates all count, but pick an allover routine instead of just toning one or two muscle groups.