The American College of Sports Medicine (ACSM) recommends that most adults engage in at least 150 minutes of moderate-intensity exercise each week, but surveys indicate that the number one objection raised to meeting that goal is a lack of time. However, that may change with the growing popularity of the 10-minute workout. The workouts, sometimes referred to by devotees as "exercise snacking" substitute intensity for duration. Liz Neporent, co-author of "The Thin in 10 Weight-Loss Plan," says science is discovering that if you increase the intensity of your exercise routine, you can decrease the time needed to benefit. Neoporent and co-author Jessica Smith recommend a hybrid of cardio and strength exercises to experience benefits. According to the ACSM, multiple shorter sessions of at least 10 minutes are acceptable alternatives to the traditional 30-minute workout and even people unable to meet the minimums will still benefit from some activity. But for the middle-aged or older, high-intensity exercise carries risks as well. Studies indicate that inappropriately intense exercise is a contributing factor in the majority of heart attacks and other cardiovascular accidents. Experts recommend that the intense short-burst workouts only be attempted by people who are already moderately active on a regular basis.