Pregnancy And Exercise: Is It Safe?

Does remaining physically inactive actually protect the woman and the fetus? Is exercising safe?
* This article is only meant to inform, not diagnose. The information presented does not replace talking with your doctor. If you are pregnant, talk to your doctor about exercising and follow his recommendations.

It was previously thought that when a woman becomes pregnant she should stay off her feet and avoid physical activity. This recommendation was instilled to protect the safety of the woman and the fetus. But, does remaining physically inactive actually protect the woman and the fetus? Current research says NO. Inactivity in fact has many negative effects.

Negative Aspects of Pregnancy

Pregnancy can negatively affect a woman in many ways. This includes:

  • Nausea
  • Fatigue
  • Back pain
  • Low self-esteem/Depression
  • Gestational diabetes
  • Excessive weight gain, which can lead to obesity
  • Reduced energy
  • Insomnia
  • Constipation
  • Shortness of breath
  • Swelling

These negative effects can hurt the woman's health after giving birth as well. But one does not have to experience these pains because there is a way to alleviate and ease them through exercise.

Positive Benefits of Exercise During Pregnancy

Because the choices a woman makes during pregnancy can affect her health for the rest of her life, it is important that she makes wise decisions during that time. Exercising during pregnancy, when adhering to the advice of their doctor, is one of the wisest decisions a woman can make. As mentioned, exercise alleviates many of the negative pains experienced during pregnancy. It has been shown that exercise reduces nausea, fatigue, and back pain while improving energy and self-esteem (Artal, 1999). Because exercise releases endorphins, a hormone which relieves pain, in the brain, it also enhances one's mood.

Gestational diabetes mellitus (GDM) is a growing concern. "GDM is the most common complication of pregnancy, affecting about 5% of pregnant women." (Brown, 2002) Several studies have shown that exercising during pregnancy improves glucose utilization due to increased insulin sensitivity, which normalizes blood sugar levels (Artal, 1999).

Excessive weight gain during pregnancy is a dangerous trend. Most women never regain their pre-pregnancy weight. In fact, pregnancy can lead to obesity. Women gain an average of 2.2 pounds a year after giving birth (Pirisi, 2001). As shown in many studies, exercising during pregnancy can reduce excessive weight gain and decrease the risk of developing obesity (Bakoulis, 2001).

Exercising can also increase a woman's strength. This will make carrying the baby, once it is born, as well as diaper bags and car seats easier (Bakoulis, 2001).

Perhaps the most beneficial benefit of exercising during pregnancy is having an easier labor. By exercising, a woman can increase her strength, endurance, and overall ability to work with her condition, which makes the task of giving birth less strenuous (Artal, 1999). No doubt, every woman would appreciate this.

What Type Of Exercise Should NOT Be Done?

First, here is what a pregnant woman should avoid:

  • Exercising in hot and/or humid conditions
  • Dehydration
  • Exercising in the supine position (The gravid uterus compresses the inferior vena cava, a main artery, thereby reducing venous return... blood flow to the heart.)
  • Contact sports (Football, boxing, wrestling, etc.)
  • Activities that could result in falling (Running, skiing, mountain biking, etc.)
  • High altitude exertion
  • Scuba diving (Could cause air embolism)

Also, the woman should not start an activity, such as running or jogging, if she is not experienced in it.

What Type Of Exercise Should Be Done?

The American Council of Sports Medicine recommends that everyone should exercise for at least 30 minutes on most, if not all days. This recommendation holds strong for pregnant women as well (Artal, 2003).

Type of Exercise

Aerobic exercise consisting of continuous, rhythmic movements that use large muscles is highly recommended. Examples of appropriate activities include, walking, cycling (stationary or machine), aerobic dance, rowing, and swimming. Swimming is considered one of the best exercises a pregnant woman can participate in because the water supports her body; therefore there is no impact on the joints. This is extremely important because during pregnancy, a woman's joints are looser because of hormone levels (Salmon, 1993).

Weight lifting when done in moderation is also safe. Pregnancy is not a time to try to increase your one repetition maximum on certain lifts or set new personal records. Lifting light weights with moderate repetitions helps maintain flexibility, muscle tone, and minimizes the risk of injury (Artal, 1999).

Duration and Intensity of Exercise Session

For previously sedentary women, 20 to 30 minutes at a moderate pace is safe. Previously active women, with no medical complications, can continue exercising close to accustomed ways. As mentioned, pregnancy is not a time to up your intensity or strive to beat your personal bests. Research shows that for aerobic exercise, an intensity of 60-70% of ones maximum heart rate or 50-60% of ones maximal oxygen uptake is safe. Studies also show that exercising at 80% of ones maximum heart rate produced no adverse effects, but it is better to play it safe (Artal, 2003).

*As with all exercise, remember to properly warm-up and cool down during each session.*

Is Exercise Safe for the Fetus

The main reason exercise during pregnancy was frowned upon in the past was fear of harming the unborn baby. There is concern that exercise challenges maternal thermoregulation (heat regulation) during pregnancy, but studies have found that humans have compensatory mechanisms that combat this (Brown, 2002). These mechanisms include increased minute ventilation and skin blood flow. These help dissipate heat during exercise. Studies have also found that there is no association between increased maternal temperature and risk of fetus malformation (Brown, 2002).

Exercise has also been found to improve uterine blood flow and placental growth. This results in heavier, longer babies (Pirisi, 2001).


Exercising during pregnancy is safe IF, and I repeat IF, there are no medical complications. In some cases, exercise is not recommended. It is of extreme importance that you talk with your doctor before beginning an exercise program to make sure it is safe for both you and the fetus. Follow the recommendations giving to you by your doctor.

Helpful Links

Works Cited

Artal, R., O'Toole, M., White, S. Guidelines of the American College of Obstetricians and Gynecologists for Exercise During Pregnancy and the Postpartum Period. London: British Journal of Sports Medicine, 2003.
Artal, Raul M.D., DiNubile, Nicholas A. M.D., and Sherman, Carl. Exercise During Pregnancy. Minneapolis: The Physician and Sports Medicine, 1999.
Bakoulis, Gordon. All The Right Moves. San Francisco: Parenting, 2001.
Brown, W. The Benefits of Physical Activity During Pregnancy. Journal of Science and Medicine in Sport, 2002.
Lumbers, E.R. Exercise in Pregnancy: Physiological Basis of Exercise Prescription for the Pregnant Woman. Journal of Science and Medicine in Sport, 2002.
Morse, Michele. A Little Exercise Goes A Long Way. Bergenfield: Parents, 1994.
Pirisi, Angela. Bigger is Better. New York: Psychology Today, 2001.
Salmon, Dena. Swimming: The Perfect Pregnancy Exercise. Bergenfield: Parents, 1993.