Before you make a decision on how much exercise you need, you should have a good idea of your exercise goal or goals: Are you exercising for physical fitness, weight control, or as a way of keeping your stress levels low?

Exercise: How Much You Need

"How much exercise is enough for what?," asks David Bassett, Jr., PhD, a professor in the department of exercise, sport, and leisure studies at the University of Tennessee in Knoxville.

For general health benefits, a routine of daily walking may be sufficient, says Susan Joy, MD, director of the Women's Sports Health Program at the Cleveland Clinic.

If your goal is more specific — say, to lower your blood pressure, improve your cardiovascular fitness, or lose weight — you'll need either more exercise or a higher intensity of exercise. So figure out your goals first, then determine what type of exercise will help you meet them and how much of that particular exercise you'll need to do.

According to the U.S. Centers for Disease Control and Prevention, everyone needs two types of physical activity each week: aerobics and muscle-strengthening activities. Aerobic activity involves repetitive use of the large muscles to temporarily increase heart rate and respiration. When repeated regularly, aerobic activity improves cardio-respiratory fitness. Running, brisk walking, swimming, and cycling are all forms of aerobic activity.

Muscle-strengthening activities are designed to work one or more muscle groups. All of the major muscle groups — legs, hips, back, abdomen, chest, shoulders, and arms — should be worked on two or more days each week. Lifting weights, working with resistance bands, and doing pushups are all are forms of muscle-strengthening activities.

Adults need at least 150 minutes of moderate-intensity physical activity each week, in addition to muscle-strengthening activities. If activity is