Physical Activity and Weight Control

Research consistently shows that regular physical activity, combined with healthy eating habits, is the most efficient and healthful way to control your weight. Whether you are trying to lose weight or maintain it, you should understand the important role of physical activity and include it in your lifestyle.

How Can Physical Activity Help Control My Weight?

Physical activity helps to control your weight by using excess calories that otherwise would be stored as fat. Your body weight is regulated by the number of calories you eat and use each day. Everything you eat contains calories, and everything you do uses calories, including sleeping, breathing, and digesting food. Any physical activity in addition to what you normally do will use extra calories.

Balancing the calories you use through physical activity with the calories you eat will help you achieve your desired weight. When you eat more calories than you need to perform your day's activities, your body stores the extra calories and you gain weight. When you eat fewer calories than you use, your body uses the stored calories and you lose weight. When you eat the same amount of calories as your body uses, your weight stays the same.

Any type of physical activity you choose to do--strenuous activities such as running or aerobic dancing or moderate-intensity activities such as walking or household work--will increase the number of calories your body uses. The key to successful weight control and improved overall health is making physical activity a part of your daily routine.

What Are the Health Benefits of Physical Activity?

In addition to helping to control your weight, research shows that regular physical activity can reduce your risk for several diseases and conditions and improve your overall quality of life. Regular physical activity can help protect you from the following health problems. Studies on the psychological effects of exercise have found that regular physical activity can improve your mood and the way you feel about yourself. Researchers also have found that exercise is likely to reduce depression and anxiety and help you to better manage stress.

Keep these health benefits in mind when deciding whether or not to exercise. And remember, any amount of physical activity you do is better than none at all.

How Much Should I Exercise?

For the greatest overall health benefits, experts recommend that you do 20 to 30 minutes of aerobic activity three or more times a week and some type of muscle strengthening activity and stretching at least twice a week. However, if you are unable to do this level of activity, you can gain substantial health benefits by accumulating 30 minutes or more of moderate-intensity physical activity a day, at least five times a week.

If you have been inactive for a while, you may want to start with less strenuous activities such as walking or swimming at a comfortable pace. Beginning at a slow pace will allow you to become physically fit without straining your body. Once you are in better shape, you can gradually do more strenuous activity.

Moderate-intensity Activity

Moderate-intensity activities include some of the things you may already be doing during a day or week, such as gardening and housework. These activities can be done in short spurts--10 minutes here, 8 minutes there. Alone, each action does not have a great effect on your health, but regularly accumulating 30 minutes of activity over the course of the day can result in substantial health benefits.

To become more active throughout your day, take advantage of any chance to get up and move around. Here are some examples:

The point is not to make physical activity an unwelcome chore, but to make the most of the opportunities you have to be active.

Aerobic Activity

Aerobic activity is an important addition to moderate-intensity exercise. Aerobic exercise is any extended activity that makes you breathe hard while using the large muscle groups at a regular, even pace. Aerobic activities help make your heart stronger and more efficient. They also use more calories than other activities. Some examples of aerobic activities include: To get the most health benefits from aerobic activity, you should exercise at a level strenuous enough to raise your heart rate to your target zone. Your target heart rate zone is 50 to 75 percent of your maximum heart rate (the fastest your heart can beat). To find your target zone, look for the category closest to your age in the chart below and read across the line. For example, if you are 35 years old, your target heart rate zone is 93-138 beats per minute. 
Age                     Target Heart Rate Zone 50-75%        Average Maximum Heart Rate 100%
                                                                                                                                                                                                        
20-30 years               98-146 beats per min.                   195
31-40 years               93-138 beats per min.                   185
41-50 years               88-131 beats per min.                   175
51-60 years               83-123 beats per min.                   165
61+ years                 78-116 beats per min.                   155
To see if you are exercising within your target heart rate zone, count the number of pulse beats at your wrist or neck for 15 seconds, then multiply by four to get the beats per minute. Your heart should be beating within your target heart rate zone. If your heart is beating faster than your target heart rate, you are exercising too hard and should slow down. If your heart is beating slower than your target heart rate, you should exercise a little harder.

When you begin your exercise program, aim for the lower part of your target zone (50 percent). As you get into better shape, slowly build up to the higher part of your target zone (75 percent). If exercising within your target zone seems too hard, exercise at a pace that is comfortable for you. You will find that, with time, you will feel more comfortable exercising and can slowly increase to your target zone.

Stretching and Muscle Strengthening Exercises

Stretching and strengthening exercises such as weight training should also be a part of your physical activity program. In addition to using calories, these exercises strengthen your muscles and bones and help prevent injury.

Tips to a Safe and Successful Physical Activity Program

Make sure you are in good health. Answer the following questions* before you begin exercising.

  1. Has a doctor ever said you have heart problems?
  2. Do you frequently suffer from chest pains?
  3. Do you often feel faint or have dizzy spells?
  4. Has a doctor ever said you have high blood pressure?
  5. Has a doctor ever told you that you have a bone or joint problem, such as arthritis, that has been or could be aggravated by exercise?
  6. Are you over the age of 65 and not accustomed to exercise?
  7. Are you taking prescription medications, such as those for high blood pressure?
  8. Is there a good medical reason, not mentioned here, why you should not exercise?
*Source: British Columbia Department of Health

If you answered "yes" to any of these questions, you should see your doctor before you begin an exercise program.