Although women may not feel like running a marathon, most of them benefit greatly from exercising throughout their pregnancies. However, during that time, pregnant women should discuss exercise plans with their doctors or another health care provider, and make a few adjustments to their normal exercise routine. The level of exercise recommended will depend, in part, on woman's level of pre-pregnancy fitness. However, many people wonder if there are more benefits or side effects of exercising during pregnancy.
What are the benefits of exercising during pregnancy?
Of course, exercise is a big plus both for the woman and for her baby, especially if complications limit her ability to exercise throughout the pregnancy. Moreover, exercise during pregnancy can help one feel better. At a time when the woman wonders if this strange body can possibly be her own, exercise can increase her sense of control.
Exercise could also boost a pregnant woman’s energy levels. Not only does it make her feel better by releasing endorphins (chemicals occurring naturally in the brain), but appropriate exercise can also relieve backaches and improve the woman’s posture by strengthening and toning the muscles in her back, butt, and thighs. It could reduce constipation by accelerating intestine movements, prevent wear and tear on the joints (which become loosened during pregnancy due to normal hormonal changes) by activating the lubricating synovial fluid in them.
Exercise could also help a pregnant woman sleep better by relieving the stress and anxiety that might make her restless at night. She will probably look better because exercise increases the blood flow to the skin, giving a healthy glow.
Prepare yourself and your body for birth
Each pregnant woman should know that strong muscles and a fit heart can greatly ease labor and delivery. Gaining control over her breathing can help a woman manage pain and in the event of a lengthy labor, increased endurance can be a real help.
Therefore, a woman should try to regain her pre-pregnancy body more quickly. By continuing to exercise, she will gain less weight during the pregnancy (assuming she used to exercise before becoming pregnant). However, a woman should not expect or try to lose weight by exercising while pregnant. For most women, the goal is to maintain their fitness level throughout the pregnancy.
Exercise has become a vital part of many women's lives. However, theoretic concerns have been raised about the safety of some forms of exercise during pregnancy. Because of the physiologic changes associated with pregnancy, as well as the hemo-dynamic response to exercise, some precautions should be observed with exercise. The physician should screen for any contraindications to exercise. The doctor should also encourage patients to avoid overly vigorous activity, especially in the third trimester. During that time most pregnant women have a decreased tolerance for weight-bearing exercise. Adequate hydration and appropriate ventilation are important in preventing possible teratogenic effects of overheating and over-exercising. Pregnant women should avoid exercise that involves the risk of abdominal trauma, falls, or excessive joint stress. This happens in contact sports and vigorous racquet sports.
In the absence of any obstetric or medical complications, most women can maintain a regular exercise regimen during their pregnancies. Some studies have found a greater sense of well-being, shorter labor and fewer obstetric interventions in physically well-conditioned women.
More about exercise during pregnancy
The benefits of regular exercise for non-pregnant women are generally acknowledged, and an exercise regimen has become an integral part of daily life for many women. However, theoretic concerns arise regarding the effects of exercise on pregnant women. Objective data on the impact of exercise on the mother, the fetus and the course of pregnancy are limited. The results of the few studies in humans are often equivocal or contradictory. Although various exercise guidelines are available, they are usually conservative and frequently based on controversial opinions, so consequently, the pregnant woman and her physician may be uncertain about the safety of exercise during pregnancy.
Physiologic changes of pregnancy
There are some important physiological changes during pregnancy that a woman should keep in mind.
Musculoskeletal changes – This is one of the most obvious changes in pregnancy, an alteration of the woman's body, including mechanical changes related to the weight of growing breasts, uterus, and fetus. This could also increase lumbar lordosis, resulting in a shift in the woman's center of gravity, causing problems with balance. In addition, weight-bearing exercise becomes a greater concern when vertical impact forces are further increased during pregnancy. These vertical impact forces, which should usually be taken at twice an individual's body weight, are further increased during pregnancy. Sudden movements may exacerbate these mechanical difficulties and increase the potential for injury for pregnant woman.
Most women report greater discomfort with exercise in the later stages of their pregnancies. Abdominal and pelvic discomfort from weight-bearing exercise is most likely secondary to tension on the round ligaments, increased uterine mobility, or even pelvic instability. Increases in joint laxity may lead to a higher risk of strains or sprains, because during pregnancy, hormonal changes are thought to induce a greater laxity in joints. This assists the softening of the pubic symphysis to accommodate delivery. One study has demonstrated increased mobility of the metacarpophalangeal joints, but an increased injury rate in pregnant patients has not been documented.
Maternal and fetal temperature – The metabolic rate increases during both exercise and pregnancy. This results in greater heat production. Fetoplacental metabolism generates additional heat, which maintains fetal temperature at 0.5 goes to 1.0°C or 0.9 to 1.8°F above maternal levels. Theoretically, when exercise and pregnancy are combined, a rise in maternal core temperature could decrease fetal heat dissipation to the mother and some data suggest a teratogenic potential when maternal temperatures rise above 39.2°C or 102.6°F. This is especially the case in the first trimester.
Hemodynamic – Exercise acts in concert with pregnancy to increase the heart rate, stroke volume, and cardiac output, but during exercise, blood is diverted from abdominal viscera, including the uterus, to supply exercising muscles. The decrease in splanchnic blood flow can reach 50 percent and raises concerns about fetal hypoxemia. Studies of flow velocity profiles in the fetal aorta and umbilical circulation have yielded contradictory and inconclusive results still. Several factors may mitigate exercise-induced decreases in splanchnic blood flow, and these factors are increases in maternal plasma volume and heart rate, as well as decreased systemic vascular resistance. The resultant changes maximize cardiac output and optimize blood flow to the placenta and the developing fetus where these alterations in cardiovascular response to exercise may take as long as seven months to return to ante-partum levels. Maternal body position also affects cardiac output during pregnancy because after the first trimester, the supine position is associated with a 9 percent decrease in cardiac output.
Cardiac output is optimal when the patient assumes a left or right side-lying position and prolonged, motionless standing during pregnancy is associated with a decrease in cardiac output of up to 18 percent. The effect of exercise on cardiac function during pregnancy remains uncertain, despite decades of studies.
Oxygen demands – It is important to understand that adaptive changes occur in the pulmonary system during pregnancy and exercise. During rest, pregnant and non-pregnant women have an equivalent respiratory frequency, but mild increases in tidal volume and oxygen consumption are noted in pregnant women. This is presumably as an adaptive response to the increased oxygen requirement of the fetus. With mild exercise, pregnant women have a greater increase in respiratory frequency and oxygen consumption to meet their greater oxygen demand she has as pregnant. As exercise increases to moderate and maximal levels, however, pregnant women demonstrate decreased respiratory frequency. They will also demonstrate lower tidal volume and maximal oxygen consumption. The oxygen demand at high levels of activity appears to overwhelm the adaptive changes that occur at rest and this may be partially due to the obstructive effect of an enlarged uterus on diaphragmatic movement.
Energy demands – Both exercise and pregnancy are associated with a high demand for energy a woman needs. In the first two trimesters, an increased intake of 150 calories per day is recommended. An increase of 300 calories per day is required in the third trimester. Caloric demands with exercise are even higher, although no studies have focused on exact requirements, so competing energy demands of the exercising mother and the growing fetus raise the theoretic concern that excessive exercise might adversely affect fetal development.