Temperature changes during pregnancy: During pregnancy, your body temperature is reset by the hormone progesterone at 0.5 °C higher than normal. Heat is also generated, even while you rest, by the extra work being done by maternal tissues and the metabolic work of growing your baby.
If your core temperature remains elevated for extended periods at critical times during the first thirteen weeks of your pregnancy, you may place your baby at risk of developmental defects. Your core temperature should not rise to or remain above 38°C for extended periods. Do not sunbake or use hot baths, saunas or spas because these activities can raise your temperature.
IMPLICATIONS FOR EXERCISE
- you need to be careful not to exercise so intensely that your temperature rises above the maximum of 38°C It is difficult to perceive a changed core temperature until it is already high; however, if you follow the guidelines regarding exercise intensity and duration outlined in this book, your temperature should remain within safe limits.
- you should not exercise if you are ill with a fever or exercise in a hot, humid environment because both situations have the potential to raise your core temperature above safe limits.
Simple precautions you can take to limit a rise in body temperature are:
- drink water before, during and after exercise (that is, ensure good hydration).
- wear loose, light cotton clothing while exercising.
- exercise in a cool, well-ventilated environment.
- limit the intensity and duration of your exercise.
ADRENALINE RESPONSE
The normal group of adrenaline hormones released by everyone as they exercise have specific effects during pregnancy:
- they can act as a stimulant to your uterus, causing contractions
- they normally play a part in directing the blood flow to your working muscles and away from your internal organs during exercise — the uterus is considered one of the organs that may have blood diverted away from it during pregnancy
- they help stabilise glucose levels at mild to moderate levels of exercise, but this effect is reduced during strenuous exercise. Your baby may then be at risk of having a low-blood sugar level during your exercise.
IMPLICATIONS FOR EXERCISE
- you need to limit your exercise intensity to 'somewhat to moderately hard' and maintain your target heart.
- you should limit your moderately hard' exercise to 15 minutes duration in your work-out (unless you have specific advice from your medical or exercise consultant).
- if you have had a history of miscarriage, you should discuss your intended exercise program with your medical consultant, preferably prior to conception.
