Some exercise is healthy for you during pregnancy, as long as it is not excessive or strenuous. Women who exercise regularly during pregnancy gain less weight and body fat than women who are less active; but their weight gain stays within normal limits, and their babies are as healthy as those of women who are inactive. Additionally, the labor and delivery of very active women tend to present fewer difficulties.

If you are accustomed to sports, you may continue to participate. Remember to stop when you get tired. If your pregnancy affects your sense of balance, walking may be preferable to more rigorous exercise. Your health care professional will tell you how much exercise you need and may also recommend special exercises to tone your muscles in preparation for childbirth.

Activity keeps you fit.
Before you become pregnant, activity and exercise ensure that your body is fit enough to carry a healthy baby to term. After you become pregnant, exercise builds muscles to protect your joints and spine. Being pregnant will make great demands on your body, and exercise can help you meet those demands.

If you have been exercising, you may want to continue in the same way you did before pregnancy. Or you may want to start a new form of exercise. In either case, always seek advice from your health care professional first. The important point is that the more active and fit you are, the less chance there is that you will be stiff and achy as your pregnancy continues.

Tips on staying active
No matter what exercise program you and your health care professional have decided on, there are a few basics you need to know about keeping fit. The following are a few exercise considerations:

• Never exercise to the point of fatigue or continue an exercise that causes you pain. You should be able to breathe easily while exercising; if you are out of breath, your baby is too. Measure your heart rate (your health care professional will show you how) at the peak of your exercise. Your heart rate should not exceed 140 beats per minute.
  
  
• Even if you have never exercised, you can walk. If you are just starting to walk, go slowly and work up to 20 minutes a day. Don't worry about the speed at which you walk or the distance you cover—this isn't a race. In general, avoid competitive activity.
  
  
• Swimming is an excellent exercise that you can continue until term. Swim slowly and gently, and avoid cold water. You can also continue with bicycling and dancing during the first and second trimesters, but not acrobatics. Horseback riding and skiing are discouraged because of the risk of falling.
  
  
• There are special exercise classes for pregnant women in many community centers. Having a teacher to encourage and to correct your position may be helpful if you are new to exercise.
  
  
• Exercise should be regular and rhythmic. Try exercising to music.
  
  
• Even if you can't do your full exercise routine, do some exercise every day. Regular exercise is better for you than occasional exercise. Exercising with a partner may help you stick with it.
  
  
• Ask your health care professional about exercises you can do in a chair.
  
  
• Warm up first, whatever the exercise may be. Try 5 minutes of slow walking or stationary cycling with low resistance. Before you exercise, take a few deep breaths to get the blood flowing around your body and to send a good supply of oxygen to your muscles.
  
  
• When you stop exercising, cool down with gentle stationary stretches.
  
  
• Take a drink of water before and after you exercise, and, if necessary, stop your exercise for a drink.
  
  
• To avoid cramps, try not to point your toes for a long time.
  
  
• If you feel any unusual symptoms during or after exercise, stop the exercise and call your health care professional.

Below are instructions for some exercises you may find helpful during pregnancy.

Basic exercise position
Lie on your back, knees bent, feet about 12 inches apart, soles flat on the floor. Your head and shoulders should be supported by cushions with your arms resting flat at your sides. This exercise position should be used only through the 4th month. After that time, exercising flat on your back is not recommended, because the growing uterus can put excessive weight on major blood vessels.

Be sure to check with your health care professional before you do these or any other exercises. Also, consult your health care professional if you develop any unusual symptoms while exercising.