Exercise During Pregnancy
Motherhood is an extreme sport, train accordingly!
Happy New Year! Now that the holidaze is over, we find ourselves mapping out our goals and intentions for the new year. January is especially notorious for being a time of making new health goals; lifting more, being more consistent, joining a gym, losing weight, “dry January”, eating more whole foods. Cue curveball: After all that quality time with your partner during quarantine you’ve become… PREGNANT!! Now the big question is - “what exercise is safe for me and baby?! How much can I lift? How high can my heart rate get? What exercises can I do and what exercises should I avoid?”
There is a lot of misinformation around exercise during pregnancy, so we thought it appropriate to dedicate a blog to this topic. The most common recommendations our patients hear:
“Don’t lift anything heavier than 25 pounds”
“Only do bodyweight exercises”
“Only continue doing whatever you were going before becoming pregnant”
Research is emerging more and more on this topic, so let’s dive into what we do know regarding exercise, pregnancy and babies.
We know exercise during pregnancy is beneficial for both Mom and baby. Research has shown that exercise during pregnancy is correlated to decreased labor time, pain, increased maternal and fetal health. “But how should I work out? How often? Do the same recommendations apply during non-pregnancy? Is there a heart rate that is more or less beneficial for the mother and the baby?” Turns out, there are answers to all of these questions. If you are interested in learning more about this topic on your own, we highly recommend the work of Dr. Clapp. Dr. Clapp wrote a book called “Exercising During Your Pregnancy”, and has published several articles in this area.
For starters, the most basic recommendation is to keep doing what you were doing prior to pregnancy. Were you running 5 miles a day? Great, while pregnancy is not a time to be upping your mileage, there is no reason to avoid maintaining that level of exercise. Were you participating in weightlifting or Crossfit? Awesome. Again, this is not a time to be maxing out on any 1 RM (rep max), but there is no reason you can’t stay in the range of 50-70% of your lifting capabilities, while maintaining good form and breathing mechanics. Do you see why an arbitrary weight lifting limit of 25 pounds doesn’t make sense? Everyone starts out pregnancy with different fitness levels. 25 pounds may be too heavy for some and completely understimulating for others. Not to mention - second time pregnant mamas with toddlers running around are lifting far more than 25 pounds!
The best rule of thumb is to base your activity on your heart rate. A systematic review Nascimento et al in 2012 reported that women who were previously sedentary should maintain exercise in the low intensity range while women who were active prior to pregnancy should maintain a moderate to high intensity throughout their pregnancy. Read that again - women who were sedentary prior to pregnancy should STILL attempt to start a gentle exercise routine if they can manage it. The benefits, which we will describe below, are too important to dismiss, for you and your baby. Let’s look a little more specifically at these numbers.
A low intensity would be anything in the 40-55% range of your maximum heart rate. You will calculate this by subtracting your age from 220, and then multiplying that number by 40-55%. For example, a 30 year old would maintain a heart rate between 76-105 bpm for low intensity work. Moderate intensity would be in the 50-70% range, so a 30 year old’s heart rate would range between 95-133 bpm while exercising. Again, it is hard to say which exercises are most effective at getting the heart rate up to these numbers, as it would depend on the woman’s baseline fitness. A long walk could be exhausting for some and barely change the heart rate of an avid runner. In terms of frequency, the general recommendation is at least 30 minutes a day for 5 days a week.
Let’s get to the fun stuff. What does the research say about the benefits of exercise during pregnancy? Turns out, there are tons of reasons for you to get your sweat on, not only for your health, but for Baby’s too! According to Dr. Clapp, regular exercise improves mom’s cardiovascular function, decreased weight gain and fat retention, improves labor outcomes including decreasing pre-term labor, decreasing labor time and improved recovery along with overall general improved fitness and mental well-being. Benefits to the baby include improved heart rate variability, which is a measure of the baby’s ability to tolerate stress. Babies born to exercising mothers are also leaner and have improved neurobehavioral maturation compared to their counterparts when tested at one month of age. These studies follow the children up to the age of 5, showing continued benefits noted throughout their growth.
Speaking anecdotally and personally from a physical therapist’s point of view, we also see in the clinic the marked differences of women who exercise vs those who don’t during their pregnancies. These changes range from stress management, strength, pain management, sleep hygiene, posture, and recovery rates on the postpartum side. Our general recommendation is to continue whatever previous exercise habits you were performing, while adding in specific breathing mechanics and strengthening exercises to combat the growing laxity as the pregnancy progresses. It is especially important to keep the hips, glutes, and core strong to help stabilize the spine and reduce injury as the body continues to change. Yes, it is very possible, and important, to continue core work during the pregnancy. It just looks different than your traditional crunch or sit up, which we do NOT recommend during this time.
We hope this blog is helpful in clarifying some of the misconceptions floating around about exercise during pregnancy. If you have any questions at all, feel free to reach out to us and we can help or put you in contact with a pelvic PT in your area.
Resources:
Clapp JF. Exercise in pregnancy: a clinical update. Clin Sports Med. 2000; 19: 273-286
Clapp JF 3rd. Long-term outcome after exercising throughout pregnancy: fitness and cardiovascular risk. Am J Obstet Gynecol. 2008;199(5):489.e1-489.e4896. doi:10.1016/j.ajog.2008.05.006
Nascimento SL, Surita FG, Cecatti JG. Physical exercise during pregnancy: a systematic review. Curr Opin Obstet Gynecol. 2012 Dec;24(6):387-94. doi: 10.1097/GCO.0b013e328359f131.
