Two-a-day workouts, once considered exclusive to professional sports teams and hard-core competitive athletes, have become more popular among fitness buffs with average skills and abilities.
"A lot of [two-a-day] people have a focus on wellness and their own personal goals," says Andrea Shelby, co-owner of Federal Hill Fitness in Baltimore.
Fitness experts have mixed opinions on the strategy and its benefits, however. Lynne Brick, a nationally recognized aerobics instructor and owner of the Brick Bodies chain of health clubs, says she recommends two-a-day workouts only for sedentary, out-of-shape beginners who can't make it through one long program.
"A deconditioned person can start with two 10-minute workouts a day," says Brick, "but after a few weeks, they should be able to get a [full] workout in at one time."
Dr. Andrew Tucker, director of primary care sports medicine at the University of Maryland Medical Center and head team physician for the Baltimore Ravens, suggests that people who work out twice a day know their limits.
"The disadvantage would be if they get into that environment and want to keep pushing," Tucker says.
He notes that exercisers may increase their risk of an overuse injury if they increase their workouts. But, "if they're basically not doing more and more by splitting it up, then I don't really see a significant downside."
In fact, people with time constraints may actually benefit from breaking up a large workout into two smaller sets.
A split schedule -- for example, jogging in the morning and weight training in the afternoon or evening -- also may be a healthier choice for those who try to cram a lot of high-intensity moves into a single workout.
By exercising in smaller segments, busy fitness buffs will be less likely to push beyond appropriate limits, Tucker says. And they'll get a good rest in between.