Pregnant in the Water
The following points about exercising in water need to be noted:
Your Maximum Heart Rate in water is approximately 13 beats per minute lower than when you are in your natural element. This is because gravity’s effect is lower underwater, so blood is returned more easily to the heart while you are suspended, increasing your stroke volume (the amount of blood pumped from the heart) and bringing about a drop in the heart rate. This means that your target heart rate zone needs to shift down by some 10 beats per minute.
The advantage of exercising in water is that it is the most risk and injury-free form of exercise. Because there is no jarring or impact, stress on the joints or bones is minimal, making this medium ideal for those who are pregnant, overweight, or have arthritic or joint problems. Water will both support your body weight and relieve the load on your ankles, knees and hips, and provide enough resistance (up to 7 times that of the free air) to necessitate energy-burning effort for propulsion. Extra calories will thus be burned as you work to achieve your target heart rate.
For those soon-to-be mums who are medically cleared to continue exercising, it is helpful to remember the changes the body undergoes as the state of pregnancy proceeds. The first trimester is critical, as miscarriages and birth defects most often occur in these early months. Because one visibly shows and feels fewer of the changes during this period, the unwitting exerciser may be tempted to work as hard as she has been accustomed previously.
Therefore, it is imperative for the pregnant to lower their levels of intensity by 25% when exercising. This is because the carrying mother has greater exercise tolerance than the foetus. While she may feel no discomfort, the foetus can easily overheat, as it cannot dissipate heat in the same way as its parent. The exerciser’s core temperature is directly related to the intensity and duration of exercise and she should not allow her core temperature to exceed 38*C. So, the secret is to work less hard and for shorter periods (instead of the usual 20 or more, do only 15 minutes of aerobic activity in the water). Remember, core temperature rises long before one perceives the increase, through sweating, so learn to tone workouts down (thus, it follows, stay out of saunas and steam baths during pregnancy; stay cool!)
Because the foetus should never have to compete with mother for oxygen, don’t raise your heart rate much above 145 beats per minute and accept that pregnancy means that the normal resting heart rate will be higher than before, and that this is not a sign of decreased fitness. Don’t compete with the non-pregnant, or with memories of yourself, before the change. Monitor heart rate regularly throughout a workout, to make sure you’re not over working. Exercise in the water should take the form of a gentle aqua aerobics workout, or slow breaststroke or crawl action. These movements utilise the pectoral, deltoid, triceps and some of the back muscles such as the latisimus dorsi and rhomboids, but care should be taken not to kick too strongly, esp. in the breaststroke frog action, because of the changes occurring in the pelvic area.
The pregnant exerciser should lower intensity levels to just over 60% of MHR. To monitor, lightly place tips of the first two fingers onto the radial artery, on the inside of the wrist, making sure not to use the thumb as this has its own pulse. Count the first beat as zero and time yourself for a 10 second period, at the same time counting how many times the heartbeats. Multiply the number of beats you count by six and you will have your heart rate for one minute. For example, a 30 year old will have a MHR of 190 beats per minute. Divided by 6, this will give her 32 beats in 10 seconds. 85% intensity will provide 27 beats in 10 seconds. The pregnant trainer should aim at an intensity level around 60%, some 20 beats in a monitored 10 seconds. In this way, the foetus can be protected from the mother’s overworking.
Note also that after 16 weeks, prolonged working (do no more than 2-3 mins.) in a supine position, lying on your back, is to be resisted, so cut out backstroke, in addition to butterfly stroke which is too hectic at any time for the pregnant. Pressure can reduce the flow of blood to both the placenta and the mother’s heart and head. Any dizziness should be an indication that blood flow is diminishing, so stop exercising immediately.