Exercise and the physical changes in pregnancy
Your body will undergo many changes during pregnancy. Some will affect your ability to exercise, or require you to modify your exercise routine, including:
Pregnancy hormones, soften the ligaments that support your joints.
This will make you more at risk of injury and over-stretching of ligaments (such as those in your pelvis).
You will need to take extra care to protect your joints, especially during exercise.
The joints most affected are in your lower back and pelvis. If any of them are painful or causing you to walk differently, we recommend getting assessed by your health provider.
Your feet are also affected, bearing the brunt of increased weight with flattening of your arches. As pregnancy progresses, circulation changes often lead to puffiness of your feet and ankles, especially by the end of the day.
To protect your joints:
▪ avoid high-impact exercise
▪ wear supportive shoes
▪ consider water/pool based exercise
▪ bring your knees together when changing positions e.g. when getting out of a car or getting out of bed
▪ try to maintain a good posture during exercise and during daily activities
The average weight gain during pregnancy is 10-15kg but may be higher or lower depending on the individual and factors such as having a twin pregnancy.
Weight distribution and body shape will also change.
As pregnancy progresses, the body’s centre of gravity moves forward, which can alter balance and coordination.
Increased weight will put greater stress on your joints, muscles and other soft tissues.
Pregnancy increases your resting heart rate in order to meet the increasing demand for blood supply to the growing baby. In a sense, you are already doing an aerobic workout just by being pregnant.
This means you should be mindful of the intensity of your exercise.
In healthy pregnant women, we recommend using the Borg’s talk test as a way of monitoring your exercise intensity (link to Borgs talk test).
The volume of your blood increases during pregnancy and your blood pressure generally lowers.
It is also common later in pregnancy for the flow of blood back to your heart to be affected by the weight and size of your uterus.
As such, rapid posture changes should be avoided as you might feel dizzy or light-headed.
From 16 weeks of pregnancy you should avoid exercises which require you to lay on your back - the weight of the baby and uterus can press on important blood vessels returning blood to the heart and can make you feel light-headed or nauseous.
During pregnancy, the body temperature is naturally slightly higher
Intensive or high-impact exercise may cause you to overheat to a level that is unsafe for you baby
We encourage you to:
◦ limit the effort of your exercise to ‘moderate’ intensity
◦ drink water before, during and after exercise
▪ wear lightweight clothing
▪ exercise in a cool and well ventilated environment and avoid spas, saunas or hot yoga.
Reduced energy levels at various times in pregnancy due to a multitude of reasons!
Many women become relatively iron deficient during pregnancy, and this can affect the amount of oxygen carried around your body. This can make you feel more tired.
Changes in sleep during pregnancy are common and periods of insomnia or poor sleep will contribute to reduced energy levels
Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Exercise in Pregnancy (position statement). Last updated July 2016. https://www.ranzcog.edu.au/RANZCOG_SITE/media/RANZCOG-MEDIA/Women%27s%20Health/Statement%20and%20guidelines/Clinical-Obstetrics/Exercise-during-pregnancy-(C-Obs-62)-New-July-2016.pdf?ext=.pdf
Lewis, E. 2014. Exercise in pregnancy. AFP. 43(8), 541-542
Sports Medicine Australia. Exercise in Pregnancy and the Postpartum Period (position statement). Last updated 19/07/16. https://sma.org.au/sma-site-content/uploads/2017/08/SMA-Position-Statement-Exercise-Pregnancy.pdf
Nascimento, SL, Surita, FG & Cecatti, JG. 2012. Physical exercise during pregnancy: a systematic review. Curr Opin Obstet Gynecol, 24, 387-94.
Zavorsky, GS & Logno, LD. 2011. Exercise guidelines in pregnancy: new perspectives. Sports Med, 41, 345-60.
World Health Organisation. Global recommendations on physical activity for health. 2011. https://www.who.int/dietphysicalactivity/physical-activity-recommendations-18-64years.pdf