A common question I hear from clients who have been trying to conceive and then become pregnant is “what exercise is safe for me to do?”. Overall, there is a lot of opportunity to continue to exercise while pregnant, but some information I have compiled from the American College of Obstetrics and Gynecology, The U.S. Department of Health and Human Services, and the American College of Sports Medicine may help in determining what is best specific to your situation.
In general, what can I do during pregnancy?
Individuals who were active prior to pregnancy are able to continue their prior exercise activities of weight training and cardiovascular training. Individuals who were previously inactive prior to pregnancy are encouraged to start exercising for up to 15 minutes no more than 3 days a week initially and progressively increase to 30 minutes on most days of the week.
What should I not do during pregnancy?
Avoid exercising in hot or humid environments to avoid overheating, this includes swimming in heated environments and you may consider how long you swim on hot days, as you will be at a higher risk of dehydration.
It is also advised to avoid activities that could cause trauma to the mother or fetus which could include soccer, basketball, ice hockey, roller blading, horse riding, skiing, and snowboarding. The main concern with these and other contact sport activities is impact with another object or individual in the sport or impact with the ground from falling.
Breathing during exercise is important. Breath holding, also known as a Valsalva maneuver, should be avoided.
The second and third trimesters also have specific positions it is recommended to avoid for a few different reasons. Starting in Trimester 2 laying on the stomach is avoided and modified by positions on the hands and knees. Some hands and knees positions are later avoided in Trimester 3 because of the pressure this places on the abdominals from gravity. Additionally, in the later 2nd and throughout the 3rd trimesters, lying flat on the back is advised to be minimized or avoided because the baby can place pressure on a vein that delivers blood back to your heart. Lightheadedness, dizziness, and shortness of breath are signs that the position of lying flat is obstructing some blood flow and in that instance, you should turn onto your side. Stretches done lying down can be modified by propping the torso up with pillows.
Symptoms that warrant stopping exercise:
Modifications should be made to reduce the susceptibility to any symptoms of discomfort or pain, shortness of breath, muscle weakness or cramping, chest pain, or swelling.
Exercise should absolutely be stopped if any of the following occur:
Vaginal bleeding or (amniotic) fluid leakage
Shortness of breath prior to exertion
Dizziness or feeling faint
Headache (development of a strong and sudden headache).
Chest pain
Muscle weakness
Calf pain or swelling
Decreased fetal movement
Uterine contractions that persist beyond exercise
What intensity of exercise is safe?
In the previous research conducted studying humans during pregnancy, there is none that suggests the intensity of exercise or target heart rate goals need to be modified or reduced during pregnancy. However, it is widely accepted that exercise during pregnancy should be within the exerciser’s tolerance
HR is not always the most accurate measure during pregnancy related to hormonal changes occurring and changes in total blood volume that occur. A pregnant individual’s heart rate can actually speed up 10-20 beats per minute by the time the pregnancy is full term and typically returns to normal within 6 weeks postpartum. Instead of conventional heart rate intensity monitoring, a rating of perceived exertion (RPE) scale can be a more accurate measure of exercise intensity for the pregnant person.
A RPE scale is a numerical scale from 6-20 or a modified 1-10 scale corresponding to the intensity sensed by the exerciser. The original scale was rated from 6-20 because this essentially correlated to the heart rate the exerciser had (add a zero to the numbers on the scale; most people fall around 60 bpm at rest and 200 bpm is their absolute maximum heart rate). Since not many people find it easy to place their perceived exertion level on a scale that starts at 6 and ends at 20, the scale was modified to start at 1 and end at 10. General guidelines recommend exertion levels between 12-14 (or 3-5) during pregnancy and never working to the point of exhaustion. It is always recommended that individuals consult with their doctor before beginning an exercise program to ensure that their safety is accounted for and that there are not person-specific contraindications or precautions that need to be addressed.
What about my core?
In general exercises that involve core engagement are safe during pregnancy. My biggest advice is #1) talk to your physician and/or physical therapist about what is safe for you to do, don’t consult Dr. Google. #2) know that the reason that core exercises are debated during pregnancy is because as the belly grows, the central abdominal muscle called the rectus abdominis will begin to separate. By the third trimester 100% of pregnant people will experience this phenomena. It is true that core exercises have the potential to increase diastasis rectus abdominis separation due to the increases in pressure in the abdominal cavity. With proper training to help incorporate engagement of all of the layers of abdominal muscle (fun fact, there are 4), there is significantly less risk of contributing to increased separation. During exercising, you can monitor for signs that the rectus abdominis is being placed under increased stress by observing the contour of the abdominal wall. You want to be able to observe that your bump is uniform from either side through the middle. “Tenting” or “coning” are terms used to describe the appearance of the center of the abdominals having a vertical peak where the right and left sides meet. If this is observed during exercise, modify the activity to allow for improved control. If modifying first does not improve the coning, stop that exercise for that day and make a plan to talk to a health professional about it. A PT who has taken extra specialization for pregnancy and post-partum will be able to provide cuing or help with positioning and training to assist your ability to confidently and safely perform many exercises.