Exercise During Pregnancy - FACT SHEET

Exercise during your pregnancy can be a very beneficial experience if you are conscious of the precautions to take and knowledgeable about the effects that exercise can have on you and your developing baby. The guidelines and limitations for exercise should start as soon as you know you are pregnant, or begin trying to become pregnant. If you have any specific questions or concerns please ask your personal trainer or obstetrician.

1. Understand that the limitations put on exercise frequency, intensity, and times are for the benefit of the developing baby - not for the mother. Normally, the mother can handle exercise much better than the developing fetus.

2. Avoid Overheating. Your growing baby does not have the same ability to dissipate heat as you do. Consequently, if you get overheated when you are exercising, the baby may be put at risk. This is especially true during the first trimester when the most important growth, cell reproduction and formation is occurring. To avoid overheating

  • Avoid prolonged exercise. Limit the more strenuous phase of your aerobic exercise to 20 minutes or less. Give yourself breaks during the workout to rest and cool-off.
  • Stay well hydrated. Drink plenty of water before, during and after your workout. Take a water bottle with you and make a deal with yourself to drink its entire contents by the end of the workout.
  • Do not use sweating as an indicator of how hot you may be getting. Your core temperature may rise without any accompanying perspiration.
  • Avoid exercising on hot, humid days. Use fans during hot weather.
  • Wear light, loose fitting clothing. Cotton is best.
  • Avoid saunas and steam baths at all times during pregnancy. Your core temperature may be rising without an associated  feeling of being hot.

3. Avoid high intensity exercise. Studies have indicated that when a mothers heart rate stays in a range of approximately 140bpm the fetus has no abnormal responses. However, when heart rate averaged 180bpm, indications of fetal distress were frequently present. This strongly suggests that high intensity exercise needs to be avoided. To keep exercise intensity at a safe level, follow the guidelines:

  • Change from an intermediate or advanced aerobics program to after pace program. Modify the level of impact (do mainly low-impact movements) and use less vigorous arm movements. You may have to modify your program more if you are exercising in a weight bearing mode (aerobics, jogging, using a stair climbing machine etc.) than if you are exercising in a non-weight bearing mode (swimming, cycling) This is because your increased weight will add to the overload effect of the exercise.
  • Learn how to measure your heart rate and check it regularly. For a ten second exercise heart rate check, it should be 23 beats or less. If it is higher, down the intensity and re-check in five minutes to assure that you are not working too hard.
  • Be realistic about the need to exercise in moderation. You do not need to keep up with non-pregnant participants or compete with what you were able to do before pregnancy.
  • Have a prolonged cool-down after the aerobic portion of your workout. Stopping exercise suddenly or going directly from aerobic exercise to lying on the floor can also have detrimental effects on the fetus. Gradually reduce the intensity of the aerobic phase of your workout and, after you have finished, get a drink, move around and cool off before commencing floor exercises or stretching.

4. Avoid frequent and prolonged exercise after week 28 of your pregnancy. Even with moderate exercise intensity, frequent (more than four times per week) exercise after week 28 has been associated with decreased birth weight and gestation duration.

5. An increase in your resting heart rate Is a normal response to pregnancy. If your normal resting heart around 70 bpm, it can go as high as 100 bpm at rest by the end of your pregnancy This is a completely normal physiological change and should not be taken as a sign that you are becoming less fit.

6. Limit the amount of exercise that you do lying on your back. This is of particular concern from your second trimester on. Exercising on your back (as when doing abdominal exercises) could cause a reduction of blood flow your heart and head, causing you to feel faint and light-headed. More importantly, the blood flow to the placenta and baby can decrease. Limit the amount of time on your back to 2-3 minutes and if you begin to feel at all dizzy or light-headed, turn onto your left side and rest.

7. About 30% of pregnant women will experience a separation of the rectus abdominous during pregnancy. If this does occur, abdominal exercises should cease. Even if it is not a problem, it is recommended that you support your abdominal muscle by crossing your hands over the abdominal area (bracing) when doing any crunch-type movements. Do not do full sit-ups at any time. If you continue to do crunches when pregnant, your obstetrician should regularly check the separation of your abdominal muscle. If significant separation or discomfort occurs, stop doing abdominal exercises.

8. In exercise classes, avoid the use of hand weights over 0.5 kg in weight. Heavier weights have been shown to increase the heart rate higher than 140 bpm. New Body exercise classes with no weights are a good alternative to normal aerobics classes. Avoid hand weights if pins and needles are being experienced in your hands.

9. Resistance training during pregnancy should involve low weight, high repetition work with an emphasis on endurance rather than strength training. Avoid heavy strength training. Try to avoid isometric contractions and holding your breath. Do not perform lunges or squats, these may lead to back and/or pubic pain.

10. Strengthen your pelvic floor muscles. Strong pelvic floor muscles will recover better after labour and delivery and will help to prevent stress incontinence. Follow these guidelines when doing the exercises: while seated or lying down, pretend that you are trying to stop yourself from urinating. The small muscles you are squeezing are your pelvic floor muscles. There are two types of contractions, short, quick ones and longer contractions with an emphasis on activating the deeper pelvic floor muscles. You should perform both types, doing up to 10-15 repetitions of each several times a day.

11. Wear a good, supportive bra. This helps to provide support for your enlarging and possibly tender breasts.

12. Avoid rapid changes in direction. As your body shape changes, so does your centre of gravity, which may effect your stability, balance and co-ordination. Sports and exercise classes, which involve rapid directional changes, lots of turns and twists and quick move changes, may put you at risk of injury. Either avoid thus or modify the exercises to make them simpler and less complicated.

13. Be very cautious if you are doing STEP or PUMP classes. For the same reasons as above, you may be at risk of injury or falling when stepping. From the first trimester, lower the step height - preferably working on a platform only - do not use hand weights, do not perform propulsions and do not participate in complicated Step classes. - In the second and third trimester, or at the time that you begin to show, Step classes are not ended because the changes in your body may effect your balance. Step classes should only be done by experienced pregnant exercisers and then, with extreme caution. If you have never done Step classes, don’t begin them during pregnancy. PUMP exercise classes should also be performed with caution and only by experienced PUMP exercisers. There may be risk of back or joint njury with PUMP during pregnancy.

14. Stretch gently. The hormone relaxin is in your body during pregnancy. This hormone causes increased joint laxity, which may make you more susceptible to injury. Be cautious and gentle with stretching.

15. With exercise, pregnant women sometimes experience low blood sugar levels, resulting in light- headedness or faintness. A light snack approximately 2 hours before exercise should prevent this. Carry a small carton of fruit juice to your workout in case this occurs.

16. STOP EXERCISE!! If at any time during your exercise session you feel very hot, faint, dizzy, short of breath, experience vaginal bleeding, have palpitations, blurred vision, disorientation or severe or continuous headaches STOP IMMEDIATELY!! It is also important to stop if you experience lower abdominal pain, tightness or cramping, back pain or pubic pain. If you experience any of these symptoms, consult your obstetrician.


Happy Exercising!!