Exercise that gets your heart rate up is called ‘cardiovascular exercise’ or ‘cardio exercise’. Even in the non-pregnant population, international guidelines state that we should all aim to do at least 30 minutes per day of cardio exercise.
However, the levels of impact (running, jumping, skipping and bouncing) and intensity (how hard you’re working) need to be considered when choosing cardio exercise in pregnancy.
I am pregnant – what should I change?
Impact exercise can increase pressure on already weakened muscles and joints.
When pregnant, our pelvic floor muscles and abdominal muscles undergo a large amount of change. Firstly, there is considerable physical stretch both downward onto the pelvic floor muscles, and outward into the abdominal muscles, putting both these muscle groups at a mechanical disadvantage and making us have to work harder to use them for daily activities and exercise.
Secondly, pregnant bodies produce relaxin, a hormone that helps to make tissues more flexible. This is terrific for preparing the pelvis for childbirth, but we need to remember that it can also increase laxity in the pelvic floor and abdominal muscles, as well as all of our other body joints like the ankles, knees and lower back.
While impact exercises like running and jumping are not in the category of exercises that could harm the baby, it is worth considering the pros and cons of continuing exercises that would put extra pressure on areas that are already at risk of damage, like the pelvic floor muscles and the lower back and pelvic joints. Avoiding these types of jolting exercises and swapping them for low impact options could reduce your risk of common issues like bladder incontinence and pelvic girdle pain, and improve your recovery after birth. This would be especially important during the second and third trimesters as the baby’s weight increases.
Exercising at high intensities in pregnancy can be unsafe for your baby
During pregnancy, your heart has to pump blood (containing all-important oxygen and nutrients) to two bodies instead of one, and as the baby grows all of your abdominal contents are pushed upwards, putting pressure on your heart and lungs. These reasons are why you might feel more breathless at low levels of exercise, and why it is very important to avoid exercising at high intensities that could limit blood and oxygen flow to the baby.
In general, it has been found that monitoring heart rate in pregnancy is not a very accurate reflection of the blood flow to the baby. Instead, it is recommended to use a ‘Rate of Perceived Exertion’, and to not get above the level of 14 out of 20.
In real terms, this usually means exercising at a level where you could still hold a conversation (but not necessarily still be able to sing!), which is referred to as the ‘Talk Test’. This may differ with elite, high level athletes, who have been shown to be able to exercise at a higher intensity during pregnancy with no ill effect to the baby, but this should be discussed with a health professional.
So what type of cardio exercise would be ideal for pregnancy?
Some ideas for low impact, pregnancy-friendly cardio exercise include:
Resistance circuit or interval training
Exercise such as aqua aerobics and interval training should ideally be taught to pregnant women by physiotherapists or fitness professionals who specialise in pregnancy and understand how to modify exercise to keep pregnant women safe.
Here is an example of a circuit routine you can try at home with a small pair of hand weights, you could try 3 rounds of 5-10 reps of each and monitor with the Talk Test:
Squats with forward double punches
Calf raises with overhead reaches
Mini-lunges (note that this may need to be avoided in those with pelvic girdle pain)
Forward punches, cross-body forward punches
Upward punches, cross-body upward punches
The team at FitRight would love to help you keep up your cardio fitness during pregnancy in the safest way possible
Our FitRight Bump&Me exercise classes are run by highly trained physiotherapists all around Perth, and include pilates-style exercises interspersed with low impact cardio workouts.