What’s the Best Time to Exercise?

We may even be less prone to injury if we hit the gym or the pavement later in the day. That’s because our core body temperatures are higher at that time, making our muscles and joints more adaptable to exercise. But rolling out of bed for a workout doesn’t mean you’re doomed for injury, notes Felicia Stoler, an exercise physiologist and author of "Living Skinny in Fat Genes: The Healthy Way to Lose Weight and Feel Great."

“Morning exercisers will only get injuries if they don’t do something to warm up first,” says Stoler. But that doesn’t mean stretching, which Stoler says can lead to injuries when your muscles aren't warmed up. Instead, she suggests opting for a brisk walk, light jog or jumping jacks.

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When it comes to weight loss, it’s a toss-up between mornings and evenings. In a study of post-menopausal women, participants were split into two groups. One group walked in the morning, while the other walked in the evening. At the end of the study, evening strollers did better overall with weight loss, losing more fat mass than morning walkers.

On the flip side, research shows that exercising in a fasted state—which is usually only possible before breakfast—is better for weight loss because our bodies burn a greater percentage of fat for fuel during exercise, instead of relying on carbohydrates from food.

Bottom line: Don’t sweat the time of day too much—just break a sweat whenever you can. “When it comes to weight loss, the key is to exercise whenever you can get it done,” advises Stoler. “It’s not always realistic to say you should exercise at a certain time. Exercise is beneficial regardless of the time of day you do it. That’s really what it boils down to.”

QUIZ: How Physically Active Are You?