It is becoming increasingly known that exercise is good for both mom and baby during pregnancy. Virtually every ache, pain and discomfort that goes along with pregnancy can be alleviated or lessened with exercise. Most women can continue with their pre-pregnancy workouts throughout pregnancy, although they may have to make certain modifications to make it more comfortable. Unfortunately, outdated guidelines are still being given out by many ob/gyns and are still found on many popular web sites. This makes it both confusing for the client and for the fitness professional who is designing a program. The previous guidelines were very conservative and based mainly on theory rather than research. New guidelines, although still conservative, are based on new evidence and give clients more choices about exercise. This article should assist you in translating these guidelines into programming for your clients.
In terms of frequency, The Centers for Disease Control and ACSM recommend the accumulation of moderate prenatal physical activity on most if not all days of the week. This moderate exercise would be equivalent to walking at about three to four miles per hour. Higher intensity workouts are considered safe three to five days per week but not recommended two days in a row. Women who exercised before pregnancy can continue throughout. Women who were totally inactive should wait until their second trimester to begin. It is agreed by most authorities that consistency is most important. Women should begin with three times per week and work up to four to five times per week. Anything less than that is inconsistent and could potentially cause harm.
Exercise prescriptions for the pregnant client should serve to improve cardiovascular and muscular status while also focusing on the specific postural challenges that occur during pregnancy. Just about any aerobic activity is appropriate if comfortable for the client. However, non weight bearing exercises are usually most comfortable, especially in later stages of pregnancy. Women who engage in non-weight bearing activities are more likely to stick with their routines throughout pregnancy. Exercise that poses risk of falling (such as skiing or mountain biking) or trauma to the abdomen such as in contact sports is not appropriate due to possible injuries.
Strength training is an important part of a prenatal routine as it supports the woman’s changing body. Because of limited research with this population, it is suggested to avoid high resistance and isometric lifting. The biggest concern is avoiding Valsalva maneuver and creating internal pressure.
For years, we have limited the motions of pregnant exercisers due to fears about instability of joints and/or imbalance. The theory a woman is more likely to become injured because of ligamentous laxity in joints due to changes in relaxin and estrogen and changes in center of gravity. Although this should be considered, there is no clear evidence showing higher musculoskeletal injuries. What this means in terms of program design is that most activities are probably safe if the client feels comfortable. To be cautious, ballistic or extreme motions should be avoided. As far as stretching goes, it is not suggested to stretch past pre-pregnancy levels.
Many changes will take place in the pregnant woman’s body that, if not addressed, will remain thereafter. The kyphotic lordotic posture so often seen with pregnancy may remain even after the baby is born if not cared for during and after pregnancy. It is important to strengthen the muscles that are weakened during pregnancy and stretch what is tightened. Create strength and flexibility programs with these changes in mind.
Even though most workouts can be safe, not all positions are appropriate for the pregnant client. A primary concern is supine exercises after the first trimester. Because of the weight of the uterus and baby on the vena cava, there is potential for supine hypotensive syndrome, where the mom and baby are at risk of lack of oxygen and blood flow. Most recent studies show that some activity on the back is safe if done in few minute segments and if the mom is asymptomatic (not lightheaded, dizzy or short of breath). Besides the risk of supine hypotensive syndrome, some ab exercises such as traditional crunches could exacerbate a diastasis recti if present.
Some excellent forms of exercise that can be used in prenatal workouts include swimming, yoga, walking, stationary cycling and low impact aerobics classes.
There is perhaps most confusion about intensity for the pregnant client. For many years, ACOG recommended working out at no more than 140 bpm. Many ob/gyns across the country continue to make this recommendation. However, in 2002, ACOG updated this guideline. It is now known that heart rate is a poor indicator of intensity for the pregnant client due to changes in blood volume and pressure. The American College of Sports Medicine recommends any activity that is equivalent to brisk walking. The guideline of 60 to 70 percent of maximal heart rate or 50 to 60 percent of maximal oxygen uptake appears to be appropriate for most pregnant women who did not engage in regular exercise before pregnancy; the upper part of these ranges should be considered for those who wish to continue to maintain fitness during pregnancy. There is controversy about the threshold for exercise and fetal stress, so it is best to stay within these guidelines. Most authorities agree that both the talk test and a rating of 3 to 5 on the Borg Scale of Perceived Exertion are appropriate measures of intensity.
The general consensus among experts is that sessions of 30 to 60 minutes of activity is appropriate for prenatal exercise. The two primary concerns in relation to long durations of exercise (over 45 minutes) are energy deficit and thermoregulation. It is of course important to take in necessary calories and nutrition to make up for whatever is expended during exercise. It is no longer appropriate to “eat for two.” In fact, new recommendations are to eat to appetite. However, it is necessary to make sure you are taking in enough calories if you are exercising, particularly for long sessions. The second concern is in regards to internal temperature. Ideally, pregnant women should exercise in cool, controlled environments. Hydration is key. The good news is that women who exercise regularly are better able to dissipate heat than women who don’t exercise regularly. Most of the research that has been done on this topic is with animals and not humans. Because in truth, we don’t know. It is better to be safe and keep moms cool during exercise, particularly during the first trimester.
Frequently Asked Questions
- Can non exercisers begin exercising when pregnant? Yes, so long as they progress gradually and commit to a consistent program. It’s inconsistency that is the biggest concern. Non exercisers are recommended to wait until the second trimester to begin.
- Can athletes continue to train while pregnant? This is a hard question to answer. Dr. James Clapp suggests that athletes may have trouble judging what is too extreme for themselves as they are so used to working through pain. Pregnant women should probably exercise within limits that do not cause severe discomfort and should, as pregnancy progresses, be prepared to moderate the intensity and duration of their exercise programs to avoid risks and injury.
- When should a client stop exercising? If your client experiences any of the following symptoms, she should stop exercising and seek medical advice:
- Vaginal bleeding
- Dyspnea prior to exertion (out of breath, prior to exercise)
- Chest pain
- Muscle weakness
- Calf pain or swelling
- Preterm labor
- Decreased fetal movement
- Amniotic fluid leakage
* ALL pregnant women should get their doctor’s approval before beginning any exercise program.
- Pate RR, Pratt M, Blair SN, et al. A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402–7.[Abstract]