Exercise has benefits throughout your life, and this is especially true in pregnancy. If you've always been involved in sports or exercise, you should be able to continue most activities in moderation. If you've never been particularly active, pregnancy can be a great time to gently begin to exercise.

Pregnancy places some hefty demands on your body, and labor is somewhat akin to a marathon. You'll find that pregnancy, labor and delivery will be easier if you are more physically fit. Besides strengthening your muscles and building bone, exercise helps your energy and may help you to sleep better at night. Your posture will improve with regular exercise, and it will reduce backaches, constipation and swelling. Regular exercise will improve your mood, too, and give you better endurance for labor. Furthermore, recent studies show that regular exercise reduces the chances for diabetes and pre-eclampsia in pregnancy. The American College of Obstetricians and Gynecologists now recommends that healthy pregnant women engage in at least 30 minutes of moderate exercise daily!

Pregnancy Changes
During your pregnancy, your body makes a chemical called relaxin which loosens ligaments that support your joints. This has its advantages for a vaginal delivery, when your pelvic bones have a little more mobility than usual. However, these changes make your joints more vulnerable to injury. As you exercise, avoid sudden jerking motions, high-impact movements and quick changes in direction. If something doesn't feel right when you are exercising, listen to what your body is telling you and don't overdo it. It's also wise to avoid contact sports and activities that could cause abdominal trauma. The extra weight you will put on in pregnancy will change your center of gravity and affect your sense of balance. Especially toward the last trimester of pregnancy, when you will be carrying 20 or more pounds, you may have back strain and notice more difficulty with your balance.

How to Begin
Speak with your health care provider to make sure you don't have any conditions which would restrict your activities. Women with significant heart disease or restrictive lung disease should not exercise. Some pregnancy conditions in which exercise is prohibited include preterm labor, premature rupture of membranes, pre-eclampsia and vaginal bleeding.

If your health care provider gives you the go-ahead, here are some guidelines for beginning a pregnancy exercise program:

• Begin slowly, and gradually work your way up to longer sessions.
• Keep well hydrated and avoid overheating. Drink water before, during and after your exercise session.
• Wear comfortable, loose clothing and a supportive bra.
• Begin with a gentle warm-up, which could last 5–10 minutes, such as walking or stationary biking.
• Then begin stretching your muscles, holding positions for 20 seconds or more. Be careful to avoid vigorous bouncing or jerking your muscles.
• After you have finished your exercise session, cool down by slowly reducing your activity.

When you exercise...
You should be able to keep up a conversation without feeling breathless while you exercise. Avoid prolonged lying on your back in the second half of pregnancy this position reduces blood flow to the uterus.

You should avoid overexertion and exhaustion—this is not the time to "go for the burn." Listen to cues from your body: rest when you're tired, drink when you're thirsty, and do not do activities that feel painful or put additional strain on your back or pelvis. If you develop pain, an irregular heart beat, shortness of breath or feel faint, stop what you are doing and contact your doctor. Make sure to eat the extra calories that exercise and pregnancy demand. During pregnancy, you should not use exercise as a way to lose weight.

Types of Exercise
There are all sorts of ways to be active during pregnancy— it's a time to explore activities which appeal to you and feel good.

Walking is the most common form of exercise and requires little preparation beyond a supportive pair of shoes. but if you develop back strain, consider trying other forms of exercise.

Water aerobics helps to keep your motions fluid, preventing sudden jerking. The water supports your weight and takes the strain off of your back.

Swimming is great for overall conditioning. The cool water can keep your body temperature down, which you may especially appreciate in hot weather. And swimming is a way to strengthen your body with minimal back strain.

Yoga provides a wonderful way to focus on breathing, stretching and strengthening your muscles. Try to find a class designed for pregnant women. Avoid holding still in standing positions for long periods of time—this could cause light-headedness.

Stationary biking is a terrific way to get aerobic conditioning without worrying about your balance…just make sure the seat you use is comfortable.

Prenatal exercise classes may be fun; just be sure your instructor focuses on low-impact activities without quick changes in direction; video tapes and books may be more convenient.

Whatever form of exercise you choose, enjoy yourself, and take pride in knowing that you'll likely have a healthier pregnancy, labor and post-partum recovery.