Your pregnant body is wired to tell you a lot about what movements feel right and wrong. There are also guidelines and experts to advise you on what aerobic exercise is and isn’t safe in pregnancy. The best advice is to combine the messages of your own body with the advice of a pregnancy exercise professional. This will help you find the type and level of cardio exercise that is right for you, on any given day, at each stage of your pregnancy.
Cardio exercise IS safe to do throughout pregnancy for most expectant mums. But, bear in mind you are looking for maintenance of your general fitness, rather than an increase in aerobic capacity or performance. You may see female athletes on TV sprinting 100m at 6 months pregnant. However, this is not considered safe for all. Moreover, the jury is still out on exactly how much and what intensity of cardio exercise is safe for the average mother to be and her unborn bub.
Some researchers suggest that during higher levels of aerobic activity the baby appears to be more active and perhaps in distress. Similarly, after a harder or longer aerobic workout the growing baby often shows less movement. Perhaps the EPOC affect, where the body is making up the oxygen deficit from the workout, leaves the growing baby with less oxygen than is optimal. On the other hand, some researchers believe this is to be unproven and think guidelines for aerobic exercise in pregnancy are too conservative.
There are however, physical changes occurring during pregnancy that cannot be denied. From very early on in the first trimester, hormones are making you more breathless. Over time the baby and diaphragm will compete for space as the baby grows, forcing you to take more frequent, shallow breaths – hence the feeling of breathlessness. This means your resting heart rate is a lot higher than usual and it is less of a jump to an exercising heart rate.
Whether you are running in the park, using a bike or rower at the gym, or taking part in an aerobics class, the same recommendations apply. Current guidelines advise keeping your heart rate under 150bpm. As the exercise heart rate equation is only an approximate and individuals differ, especially during pregnancy, relying on heart rate only in not considered an effective measurement. Also you may not own or wish to invest in a heart rate monitor. An easy way to monitor your intensity during aerobic activity is combining your heart rate with the ‘talk test’ or PRE (perceived rate of exertion).
There are many other changes happening that affect movement too. Your body weight, shape and centre of gravity are changing, as is the stability of your joints. This affects balance and how comfortable bouncy movements are. If your chosen aerobic activity involves a lot of impact and direction changes, it may need to be modified. Or you may need to look at an alternative for a while. It is less about your baby and more about keeping you uninjured.
Another factor to consider is that with a growing baby on board your body is less efficient at regulating temperature. It is not good for mum or bub to get too hot. Staying hydrated – with water and electrolytes, also becomes more important, even if the frustrating side affect is extra bathroom interruptions.
Contact a pregnancy exercise professional to run through specific guidelines for your favourite aerobic activity. Keep in touch with them so you can adjust things as and when needed. The goal is to keep you enjoying exercise safely throughout your pregnancy, even if the exercise is more gentle than what you would usually do.