Is it okay to work out twice in one day? And if so, what’s the best way to do it?

The expert: Doug Barsanti, a certified strength and conditioning specialist and owner of ReInvention Fitness in Santa Cruz, California

The answer: Logging double workouts can be safe, but it depends on two things: how long your workouts are and what you’re doing during each one. “People assume that working out more is always better than working out less, but that’s not the case—more isn’t always better, especially if you're doing the same thing,” Barsanti explains.

His advice: Doubling up can work if you :

a) separate your sessions into two smaller, 30- to 45-minute blocks and do them at the beginning and end of the day, and..

b) practice different disciplines during each one. So for example, you could go on a 30-minute run in the morning and then do 30 minutes of strength training at night, or you could do strength training early in the day and then yoga later on that evening.

What happens if you try to exercise for twice a day for longer periods of time? Your body basically collapses. “Generally speaking, working out for longer than an hour a day runs your body into the ground. You’ll get so tired that you’ll actually lose strength and therefore lose muscle—not to mention losing the enthusiasm to exercise,” Barsanti explains. Same goes for repeating the same kind of exercise. "If you don't vary it up, your body gets used to it, and it won't be as effective the second time you do it," he continues.

Your best bet: Aim for a consistent workout schedule that you can definitely stick with every week. And if you do double up, don't break the rules!