The American College of Sports Medicine (ACSM) has long advocated that adults engage in at least 150 minutes of moderate-intensity exercise each week. But for many adults, that length of time can seem daunting. That’s why the ACSM (and many noted fitness authors) are now saying that multiple shorter, higher-intensity workout sessions of at least 10 minutes are acceptable, too.

But Dr. Carl Foster, a professor in the exercise and sports science department at the University of Wisconsin-La Crosse, advises caution before starting a regimen of ‘exercise snacking’ (as these shorter workouts are called)—particularly among middle-aged and older exercisers.

Citing studies that correlate heart attacks to inappropriate levels of high-intensity exercise, Foster recommends that older athletes have a solid six months of ‘normal’ training behind them first.

Otherwise, says Foster: “You can do the work in 10 minutes, but then it takes you 40 minutes to recover." For more information about the pros and cons of short, high-intensity workouts, click here.