Q: I don’t have much time to exercise anymore. I used to work out for an hour every day but my schedule has changed and now that’s impossible. I’ve started doubling up my workouts: I take a step aerobics class followed by a weight-lifting class. Although I thought I wouldn’t be able to handle this much exercise, it’s easier than I thought. So now I work out three times a week, for two hours at a time. This gives me four free days to catch up on work and other obligations. But is working out longer, but less often, as effective as working out for shorter sessions on most days of the week?
A: You’re obviously in pretty good shape to be able to handle either variation of your routine—daily, hour-long workouts or longer, doubled-up sessions less often. So when you ask how “effective” either approach is, it really depends upon your goal.
If you’re trying to maintain your fitness level and muscle strength, either route will keep you as fit as you are.
If you’re trying to improve your cardiovascular and muscular fitness, as long as you feel sufficiently challenged during your sessions, you will give your body the stimulus it needs to improve. (And as long as you’re hydrated and well-nourished before your two-hour workouts, you should fly through them.)
If you’re trying to lose weight, it’s unclear which approach is best. From a theoretical perspective, you are burning the same amount of calories either way. So, it’s unlikely that you should notice a difference in body fat loss or weight changes. If you notice greater weight or fat loss with a different approach, it could be that you also changed the way you eat (consuming fewer calories) or the intensity at which you work (burning more calories).
The super-long sessions could give you a false impression that you’ve lost weight if you sweat profusely. Being dehydrated can seem like pound or inch loss. Chances are, though, this is only water loss and not permanent.
Working out more often might possibly lead to more fat loss. There is one school of thought that suggests exercising more frequently revs up your body’s engine more often. If a workout is intense enough, you can create a more frequent afterburn, where you use up extra calories during the hours after the workout. So exercising frequently keeps the motor running, so to speak. In contrast, long lulls between sessions, no matter how tough they are, may put your body into sleep mode and make you more prone to conserve energy.
Of course, even if the afterburn effect occurs—and you usually have to work at very high exercise intensities for it to kick in—it’s unclear whether the extra calories burned would add up to a big enough chunk of calories to lead to noticeable weight loss. If you’re only burn an extra 10 calories after each session, it could take years for that to show up as a major change in the way you look.
Calculating calories and predicting what happens with metabolism is always a gamble because there are so many influencing variables. For example, would more frequent sessions make you hungrier, canceling out any after burn calories you accrue? Or would you become more slothful during your non-workout days if you chose to limit yourself to just three exercise sessions a week—and thereby burn fewer calories all day and gain weight?
Generally speaking, it’s probably better to be active more often, simply so that you don’t settle into an overly sedentary existence. Of course, that doesn’t mean you have to do a gym workout on your days off. You could just make an extra effort to walk the dog more often or for longer periods of time, use stairs instead of elevators, and so on.
