Physical activity

• Alternative Names

  Fitness recommendations; Exercise

• Information

  Physical activity can help you:

  • Burn calories and reduce body fat
  • Control and maintain your current weight
  • Improve chronic medical conditions such as diabetes, high blood pressure, and heart disease
  • Improve your fitness and ability to perform daily activities
  • Prevent diseases such as osteoporosis and depression
  • Reduce your appetite

  RECOMMENDATIONS

  Physical activity is divided into two types of activities for adults: aerobic activity and muscle-strengthening activity.

  Aerobic activity can be of moderate or vigorous intensity. It is important to start with aerobic activities that are less intense at first, and work up to more vigorous activity.

  While performing moderate activities (such as brisk walking), you should be able to talk but not sing. Vigorous activity requires taking a breath every few words.

  You can also monitor the intensity of exercise by using your heart rate. The target heart rate during physical activity should be 60% - 90% of the maximum heart rate.

  To calculate your target heart rate, use the following formula:

  1. 220 (beats per minute) minus age = maximum heart rate.
  2. Maximum heart rate multiplied by the intensity level = target heart rate.

  For example, a 50-year-old woman exercising at 60% maximum would use the following calculation:

  1. 220 - 50 = 170 (maximum heart rate)
  2. 170 X 60% = 102 (target heart rate)

  This is her target heart rate, regardless of the type of physical activity she elects to do.

  Physical activity at 60 to 70% of the maximum heart rate is considered moderate intensity exercise. You can moderately exercise safely for a long period of time. It is best to start an exercise program with moderate intensity exercise.

  The other type of physical activity is muscle strengthening exercise. Muscle strengthening can be done with a weight program, heavy gardening, or push-ups and calisthenics.

  The amount of physical activity is very important to achieve health benefits. Any increase in activity is better than less activity.

  The recommended amount of time spent doing aerobic activity is:

  • 2.5 hours a week of moderate activity, increasing to 5 hours a week
  • Or 75 minutes of vigorous activity, increasing to 2.5 hours per week

  Muscle strengthening is recommended twice a week.

  Try to do some form of physical activity at least three times a week. Increasing to four or five times a week is even more helpful. Spread out the physical activity through the week, rather than doing it on three or four consecutive days to reduce the risk of injuries.

  People who have chronic medical conditions, are older, are pregnant, or have been very inactive may need to start with less activity and increase more slowly. Increasing both aerobic and muscle strengthening physical activity has benefits, even if you cannot reach your goals.

  BENEFITS

  Physical activity contributes to health by:

  • Decreasing the risk for cardiovascular disease
  • Reducing the amount of bone loss that is associated with age and osteoporosis
  • Reducing the resting heart rate

  Physical activity also helps the body use calories better, which helps with weight loss and maintenance. It can increase basal metabolic rate, and reduce appetite and body fat.

  SIDE EFFECTS

  Physical activity should be done at a rate that is right for you. When you increase activity gradually in both intensity and time you are unlikely to have any side effects.

  An evaluation by an exercise physiologist is helpful in order to to avoid injuries. Injuries can occur if you start physical activity too quickly, with too much intensity, or for too long.

• References

  US Preventive Services Task Force. Physical Activity Guidelines for Americans: Recommendation statement. 2008. Accessed March 1, 2009.

Review Date: 3/1/2009

Reviewed By: Linda Vorvick, MD, Family Physician, Seattle Site Coordinator, Lecturer, Pathyphysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.