In the past, most recommendations for exercise have called for a certain number of hours dedicated to physical activity. For instance, published guidelines from the Health and Human Services Department in 2008 suggested 150 minutes of moderate exercise per week — the equivalent of five 30-minute walks. The guidelines added that 75 minutes of vigorous exercise a week, such as jogging, could be substituted.
By most estimates, however, at least 80 percent of Americans don’t meet the recommendations. With the time constraints in mind, many people have turned to shorter, more intense workouts called high-intensity interval training.
But which is better for you?
The argument for traditional cardio exercise
By "traditional cardio exercise," scientists are usually referring to longer bouts of lower-intensity exercise. There are cases both for and against this type of workout. Here are some of the key research findings:
The argument for high-intensity interval training
The new hot trend in exercise is high-intensity interval training, in which short bouts of hard exercise are combined with periods of rest to create a much shorter, more focused workout. This may be better suited for the modern adult who may have limited time to get in his or her exercise. But is it any healthier than training for a longer duration?
In a study from the Norwegian University of Science and Technology, four minutes of exercise may be all you need. This short period of exercise was all people needed, according to the study, to develop endurance and health gains. However, the four-minute workout is deceiving, as it's actually 16 minutes – a one-minute interval performed at 90 percent maximum heart rate followed by a three minute rest, repeated four times. The researchers saw metabolic and cardiovascular health improvements, plus better blood sugar control and blood pressure profiles in those who used this style of exercise.
The New York Times recently published a workout that generated significant buzz, indicating that seven minutes a day may be all you need. Scientists from McMaster University in Hamilton, Ontario found a way to work out the major muscle groups for as short a period as possible, but with maximum results. The workout involves 30 seconds of each move performed at a level 8 on the one to 10 "discomfort" scale. This exercise program includes jumping jacks, wall sits, push-ups, crunches, step-ups, squats, triceps dips, planks, running in place, lunges, T-push-ups and side planks.