Exercising During Pregnancy

Pregnancy is an exciting time, and many women wonder: is it okay to keep up my exercise routine? This article discusses the role of exercise and some safety precautions during pregnancy.

During pregnancy, a lot of changes occur in your body. If you are used to exercising you may wonder if it’s okay to continue, or you may have been thinking about starting to exercise to better prepare yourself for labor.

Benefits of Exercise

Years ago, doctors cautioned their patients against exercising during pregnancy, but we now know that exercise during pregnancy has several benefits for the expectant mother.

Some studies have shown that exercise during pregnancy may shorten labor and decrease the need for interventions or surgery.

And exercise can help relieve some of the symptoms that occur as your body changes during pregnancy. Exercise can strengthen back and abdominal muscles (translation: improved posture and less backache!), help increase energy levels, and be an excellent strengthener and preparation for labor and delivery. It can also help prevent excess weight gain, and improve the quality of your sleep. And when you exercise your lower extremities, it increases the blood flow back to your heart (which helps to relieve aching varicose veins).

Your Body During Pregnancy (and How Exercise Affects It)

When you are pregnant, your body undergoes certain changes that can affect your response to exercise.

In general, it is important to look at how fit you were before your pregnancy began. You should be able to safely exercise at the same or slightly below your pre-pregnancy level.

But be sure to check with your doctor first for his/her recommendations before starting an exercise program while you are pregnant, to make sure there aren’t any medical reasons why you shouldn’t exercise.

Breathing and Circulation

As your pregnancy progresses and your unborn baby grows, your diaphragm rises and your rib cage flairs out. This makes the work of breathing more efficient and ensures that both you and your baby get enough oxygen.

But during strenuous exercise, it can be hard in the later months to get enough oxygen; so unless you are extremely well conditioned (i.e. a professional athlete), it’s a good idea to cut back a little on the intensity of your workouts during the last trimester. Be sure to listen to your body, and to stop if you become tired or dizzy. This is NOT the time to “push through” when your body says otherwise. A good rule of thumb is the “talk test,” you should be able to talk without gasping for breath as you exercise.

Your average heart rate increases by about 10 to 15 beats/minute by the third trimester, meaning your heart is pumping more blood (blood volume can increase by up to 50% by the end of the second trimester) and is working harder both at rest and during exercise.

Recovery rates after exercising are also slower after exercising. This again means that workouts need to be less intense as your pregnancy progresses, and it may take longer (up to 15 minutes) to recover to a pre-exercise heart rate after exercising.

Your veins increase their capacity to hold blood, to help make up for the increased blood volume. This means that swollen veins (such as varicose veins) can occur, which can be relieved by exercise such as walking that helps push blood back to the heart.

After the first trimester, lying on the back (supine) can cause a decreased rate of blood return to the heart (because of the weight of the uterus) which is why you should avoid exercises that involve lying in this position after the first trimester. Side-lying positions are fine, though.

Cooling Your Body

During pregnancy, blood flow increases to your skin (to help cool you down, since your metabolic rate rises) and to your uterus, kidneys and lungs. While you exercise, this blood flow is shunted back to the heart and muscles, which will compete with these other organs for blood.

It is important to avoid becoming overheated during exercise, and to drink plenty of fluids to prevent becoming overheated.

Ligaments and Joints

The round ligament, that supports the uterus, becomes stretched during pregnancy. Any extra stress on it can cause pain or discomfort in the groin area (which can be relieved by doing pelvic tilts on hands and knees).
Your joints also become more lax due to the action of a hormone called relaxin that helps to prepare your pubic bones for opening up during delivery. Because of this action, it’s a good idea to avoid overstretching or stressing your joints while exercising, instead low-impact exercises will be more comfortable.


Your center of gravity changes as your pregnancy progresses, with an increase in the lumbar curvature. This can make it easier to lose your balance, so care when exercising is important. You will want to avoid certain exercises in the last trimester that depend critically on balance, such as horseback riding, gymnastics, skating, or skiing.


Because your body uses glucose instead of fat as its primary energy source during pregnancy, even with prolonged exercise, it is important to make sure that you snack during prolonged exercise to prevent a drop in your blood sugar.

Your calorie needs rise during pregnancy, making it important to eat enough to provide sufficient calories for both you and your growing baby, and for the calories burned during exercise. If you are gaining normally at your prenatal checkups, you are probably eating enough.

Hot Weather and Exercise

If you live in a warm climate, or are exercising during the summer months, it is important to take certain precautions to avoid becoming dehydrated. Drink water both before and after exercising (and during if exercising for longer than 15 minutes) and wear cotton that allows for the evaporation of sweat. Best of all, try to exercise indoors where it is air conditioned on those really hot summer days ( indoor malls are a great place for walking), or exercise early in the day before temperatures rise.

After Delivery

Remember that your body will have to adjust gradually during the weeks after delivery and allow yourself at least four to six weeks before going back to your full pre-pregnancy exercise routine. Instead, start out gradually, and slowly work yourself back up over the weeks.

Contraindications and Precautions

It is important to realize that there can be medical conditions that make exercise unsafe during pregnancy.

Some of these include:

* Pregnancy- Induced Hypertension (PIH)

* Preterm labor (this or previous pregnancies)

* Membrane rupture

* Incompetent cervix

* Bleeding during the second or third trimester

* Retarded intrauterine growth

* Multiple pregnancy

If you have underlying heart, lung, diabetes or thyroid disease, you must be checked out by your doctor and follow his or her recommendations before starting an exercise program.

You will want to avoid any activities that could cause injury to your abdomen, especially in the last trimester (such as horseback riding, hockey, soccer, wrestling, football, or sports with projective objects such as racquetball).

You should not exercise if you have a fever since exercise elevates the core body temperature.

Also, you should stop exercising and contact your doctor immediately if any of the following occur while exercising:

* Severe shortness of breath

* Bleeding

* Cramping

* Dizziness or feeling faint

* High blood pressure

* Chest pain

* Severe joint pain

During or after exercising, some contractions may be felt, and this is considered normal later in pregnancy. But if they continue for longer than a half hour, you should contact your doctor.

Especially Beneficial Exercises

Kegel Exercises are exercises that can help strengthen the pelvic floor (which becomes stretched and weakened during pregnancy). They are also an excellent preparation for childbirth, since the muscles used when pushing are strengthened by doing these. For information on how to do this exercise, see our article, “How to Kegel”.

Other exercises that are helpful are those that strengthen your back and abdominal wall, and can help with relieving backache include:

Walking: this is one of the simplest and best exercises for overall toning and endurance while pregnant. It’s a good idea to time your walk for the early morning or evening hours in warmer weather to prevent overheating. Be sure to drink plenty of fluids, too; one pint of water before exercising and one cup of liquid every 20 minutes while you are exercising. You should also be sure to replenish any fluid lost during exercise afterwards.

Stationary cycling is also a good activity, because you will receive the aerobic benefits without the risks associated with regular bicycling (such as the potential for falling). It also does not stress joints, since it is a low-impact activity.

Swimming has several benefits. It relieves stress on joints, it is an aerobic conditioning exercise, and during hot weather, the cool water can help prevent overheating.

Pregnancy is a time when you can maintain your regular exercise routine, as long as you are aware of the special considerations discussed above. And you can also start gentle routines, such as walking on a daily basis, with your doctor’s approval, for health benefits and a possible shorter labor and faster recovery period after childbirth.

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