Exercising during pregnancy has become increasingly popular due to the large amounts of research (see part 1 of this post) that suggests that exercising throughout pregnancy is beneficial to both mother and unborn child. However, the research begs the obvious questions about how much exercise is enough to obtain the positive effects outlined in the previous post and what are the safe upper limits? The answers to both are essential for designing safe and effective training programmes.
Principles of Exercise Prescription, Exercise Programming and Safety
The majority of prescribed exercise programmes will have 4 main components which will, by and large, determine the success/outcome of any exercise programme. These components are the type of exercise ( e.g, running, cycling, weight training etc), frequency ( how often it is performed), intensity (per cent of Max HR, amount lifted, rest periods etc) and duration ( length of time devoted to the activity).
When prescribing or embarking on an exercise programme during pregnancy, these components must be looked at carefully to ensure that not only is the programme effective and safe, but that it corresponds to the level and competency and experience of the exerciser. Equally important is programme flexibility, so any programme can be adapted to accommodate the various stages of the pregnancy. As Clapp states in his book on exercising during pregnancy;
" The benefits of exercise are different in early and late pregnancy. Early pregnancy exercise improves the growth of the baby and decreases maternal symptoms. Late pregnancy exercise maintains fitness, limits weight gain, and shortens labor"
So what type of exercise is most beneficial for expectant mothers? There is clear evidence showing that weight bearing activities such as running, aerobics, and circuit style weight training have the biggest impact, quite simply because these modalities have the greatest impact on the physiology of the body and the resultant adaptations complement those of pregnancy. In his research Clapp found that the exercise threshold necessary to achieve a weight gain and fat deposition reduction for someone starting exercise at the beginning of the third month was somewhere between 20 minutes , three to five times per week, and 40 minutes, five times per week. Exercise type was weight bearing and intensity 55 per cent of maximum capacity. He concluded that,
"Regular, sustained, weight-bearing exercise is the best type of exercise for pregnant women because it clearly complements the adaptations to pregnancy. However, the proper frequency, duration, and intensity will vary from woman to woman."
The approach to exercise prescription for healthy women during the reproductive process should follow the same principles and use the same tools as those used at other times during life. A holistic approach that educates and integrates and balances the exercise with the reproductive process and other aspects of life. Neither exercise nor reproduction exists in a vacuum, and both should be monitored regularly to assess progress. Determining type, frequency and intensity of exercise throughout the reproductive process should be based upon a woman's fitness at the start and the goals she wishes to achieve. Obviously, there may be a need to cut back should evidence of overtraining appear ( chronic fatigue, pain, loss of motivation, susceptibility to injury, common infection). Conversely, an exercise regimen may need to be increased if inadequate progress is made. Adopting a common sense approach and carefully monitoring responses ( of mother and baby) are two of the best ways to evaluate and assess training progress.
As more research establishes clear benefits to exercising during pregnancy, it is likely that there will be a change in attitude towards woman who exercise before, during and immediately after pregnancy.
"Pregnancy is a normal physiological state, not a disease, and the benefits of exercise appear to be substantial for both the woman and the pregnancy..."