Your blood pressure drops in your second trimester, so it’s best not to do sports that encourage shifting position too quickly (such as getting up or squatting down rapidly). Otherwise you might be in for a dizzy spell. This blood pressure change happens because you’re growing new blood vessels to supply blood to your growing placenta.
Your baby also starts to get heavier – as you will have noticed! He or she can place pressure on the blood flow to your heart when you’re lying on your back. So after your fourth month of pregnancy, steer clear of exercise that has you assuming this position.
“Try to modify these exercises [such as lying-on-your-back leg exercises during aerobics] as most can be done lying on the side. Prolonged periods of motionless standing should also be avoided,” suggests Sports Medicine Australia (SMA).
Naturally you put on weight, too, and your centre of gravity starts to shift forward – and your spine curves more to cope.
As SMA says, “This increase in body size can make some activities more uncomfortable (eg. jogging). These changes can also alter balance and coordination.” Again this makes exercise that involves a quick change in direction challenging.
By this time, you’re probably starting to slow down on the more intense forms of exercise – as is natural and recommended.
Exercise in your third trimester should be kept to three sessions a week, or less, and preferably be of the non-vigorous nature.
Interestingly, SMA cites a study in which women who exercised very vigorously more than three times a week delivered significantly smaller bubs. Although such babies are of course easier to deliver, low birth weight can raise health concerns down the track.
Exercise tips for pregnant women
The National Health Service in the UK suggests you:
- Warm up before you exercise, and cool down afterwards
- Keep active consistently, on a daily basis, not in fits and starts. If you can, walk for at least 30 minutes a day.
- Avoid strenuous exercise when it’s hot
- Drink loads of water
- Try swimming when you’re pregnant! The water immersion supports your increased weight and lots of swimming pools offer aqua-natal classes
- If you feel unwell or experience any unusual symptoms while you are exercising, you should stop and contact your healthcare professional.
References available on request