Exercise: How Much?

It's been 13 years since the American College of Sports Medicine issued a statement on how much exercise we should be doing. And according to Carol Ewing Garber, vice-president of the ACSM and assistant professor of movement sciences at Columbia University, the organization's position needed to be updated and brought in line with other prominent health and fitness agencies.



The 26-page position statement sums up the latest scientific findings and makes a number of recommendations regarding the quality and quantity of exercise needed to achieve a basic level of fitness. The guidelines are meant to help health and fitness professionals develop effective individualized exercise prescriptions for their clientele.

At first glance, the recommendations are daunting: a total of 220 minutes (three hours and 40 minutes) spent exercising over a seven-day period, in the following way:

150 minutes of moderate-intensity cardiovascular exercise (walking, running, cycling, swimming).

Two to three weight-training and functional training workouts (exercises to improve agility, balance and co-ordination).

Two stretching sessions per week.

Before you gasp at the time investment recommended by the ACSM, Garber says the guidelines aren't meant to suggest that the average exerciser has to do it all.

"It's simply a statement of what works," she said. "You can do less and still get benefits."

Finding out how little exercise you actually need to achieve health benefits is one of the most interesting parts of the document. Despite the recommendation of 150 minutes of moderate-intensity exercise or 75 minutes of vigorous exercise per week, the ACSM admits that several studies have noted a reduction in cardiovascular disease and premature mortality starting at about half that exercise volume. And while it should be pointed out that more exercise results in more benefits, including improved fitness, it's good to know that even a little bit of exercise helps.

There's even some wiggle room in how often you're expected to exercise. Despite advice that fitness goals are best achieved by spacing your workouts evenly over seven days, Garber admits there is little data to suggest that a weekend warrior is any less fit than someone who follows a traditional 30-minute workout five times a week. So if going for a 50-minute walk or bike ride Friday, Saturday and Sunday works better with your schedule, then proceed with pride, knowing that you're meeting the ACSM guidelines for improved fitness and health.

Also interesting to note is the data regarding the use of pedometers. These popular step-counters are often used to measure physical activity and are associated with the much ballyhooed claim that it takes 10,000 steps a day to realize health and fitness benefits. The ACSM takes on this claim, first suggesting that pedometers don't provide an accurate tally of exercise volume and that it takes much less than 10,000 steps to meet standard levels of recommended daily physical activity. Daily step counts of anywhere from 5,500 to 7,900 have been demonstrated to be sufficient to meet most exercise guidelines.

As for the recommended speed of those steps, researchers suggest that a pace of 100 steps per minute makes for moderate-intensity exercise, and is an effective workout if performed for 30 minutes a weekday.

Besides the recommendations for cardiovascular exercise, the ACSM also touts the benefits of strength and flexibility training, including the length of time a stretch should be held (10 to 30 seconds) and the optimum number of sets per strength exercise (two to four sets per muscle group).

For the first time, the group's statement has addressed the importance of functional training. Seniors will benefit the most from improving their balance, agility and co-ordination, which has proved to reduce the risk of falling and enhance the ability to perform the type of physical activity associated with everyday life, like house and yard work. Younger individuals may also experience fewer knee and ankle injuries, though the ACSM admits the research among this particular age group is sparse.

While the role of exercise in the battle to lose weight is outside the scope of this document, Garber says not to forget the importance of exercise in weight loss and maintenance. She also wants to emphasize that exercise doesn't need to be hard-core to be effective. "Keep it simple," she said. "Start wherever you can. Then as you begin to exercise more regularly, you can worry about how long and how hard (you need to exercise). But the main message is get moving."