The American College of Sports Medicine, or ACSM, periodically issues position statements outlining its recommendations for exercise, fitness, weight loss and health. The group's statements are based on current scientific evidence and are widely used by doctors, exercise physiologists, coaches and and trainers to make exercise recommendations to patients, athletes and clients about exercise and weight loss.
ACSM recommends 30 to 60 minutes of moderate-intensity aerobic exercise five or more days per week, or 20 to 60 minutes minutes of vigorous aerobic exercise at least three days per week.You can mix moderate and intense workouts throughout the week. Exercise bouts don't need to be continuous. You can accumulate the recommended number of minutes in blocks of as little as 10 minutes and still receive the same cardiorespiratory benefits. If you're out of shape, gradually work up to the recommended volume and intensity levels.
The organization suggests two to three days per week of resistance training, such as weight lifting, for each major muscle group. To build strength, choose a resistance that allows for two to four sets of eight to 12 repetitions. If your goal is muscular endurance, aim for two to four sets of 15 to 20 reps. Gradually increase the resistance over time as you get stronger. Rest two to three minutes between sets and allow at least 48 hours for recovery between strength-training workouts.
ACSM also recommends at least two to three days per week of flexibility training for each major muscle group, although the organization notes that daily stretching will result in better flexibility. Both static and dynamic stretching is effective. Because warm muscles stretch more easily than cold muscles, warm up with light aerobic exercise before stretching. Hold stretches for 10 to 30 seconds at the point of tightness or mild discomfort, and repeat each stretch two to four times. ACSM also recommends exercises to develop balance and coordination, such as yoga or tai chi, 20 to 30 minutes per day, two to three days per week.
To prevent weight gain, ACSM recommends at least 150 minutes per week of moderate-intensity aerobic exercise. To lose weight and to prevent regaining it, you may need up to 250 minutes per week. This amount of exercise represents an energy expenditure of approximately 1,200 to 2,000 calories per week. However, ACSM stresses that exercise alone is less effective for weight loss than combining exercise with dietary changes. The group recommends resistance exercise for its health benefits and increases in muscle mass, but notes that resistance exercise alone does not seem to be effective for weight loss.