Peak Performance

When do you gain the most benefit from your exercise regimen? Do you like to greet the new day with a workout, or are you more energized by a late afternoon or early evening run?

Dr. Phyllis Zee, a neurologist at Northwestern University of Medicine, suggests that our circadian rhythms regular changes in mental and physical characteristics that occur in the course of a day determine the best timing for sports performance.

"The best time to work out is in the late afternoon," Zee says, "because your muscle strength is at its peak, meaning you're less likely to injure yourself. It's also a time when you are most awake and alert."

If afternoon or early evening exercise doesn't fit your schedule, though, health experts agree: It's better to exercise any time of day than not at all. If you exercise in the morning, just be sure to spend a few more minutes warming up.