Caitlin Hurley of Bedford, Mass., has two children ages 5 and 8 and is pregnant with her third. She ran until 7 1/2 months into her pregnancy with her first two children and is planning on doing the same with her third, depending on how she feels.She ran the 2013 Boston Marathon in 2:58, and her next finish line will be delivering her baby late July 2014. Each week she'll document her progress on Ultra Sound Pregnancy.
At my doctor's appointment last week, I informed my nurse that I was continuing to run and writing a blog about running and pregnancy. Since I've done so much reading about it I figured I would test her knowledge (cheeky, I know). I asked if there was a heart rate limit for exercising while pregnant, and she advised me not to stay above 140 BPM for a prolonged period. While I understand what she meant (don't go too hard for too long), her response was vague (how long is too long?) and about 20 years out of date. The American Congress of Obstetricians and Gynecologists (ACOG) took away the heart rate limit by the time the 1994 guidelines came around, recognizing that the amount of effort put out by pregnant women working at 140 BPM can vary greatly from one woman to another, and within one woman during her pregnancy. A woman's heart rate increases naturally in the first trimester, because she has a lower volume of blood pumping through her heart since she is circulating blood through her baby's body as well. Later in her pregnancy, her as her blood volume continues to increase, her heart rate will actually tend to be lower.
Confused yet? It’s no wonder that myths and outdated advice around exercise and pregnancy abound. My nurse was well intentioned in her counsel, but if I were to follow her advice not to stay at 140BPM for a prolonged period, I would have a walk about every three minutes during my runs these days. Other advice I’ve gotten includes the vague “stop exercising when you’re tired” and “listen to your body.” As an athlete, I have trained myself to ignore those feelings. Fatigue, pain, and listening to your body are not part of a runner’s vernacular. So I have had to recondition myself. I use the currently advised guidelines of RPE (rate of perceived effort) during my runs: anything harder than conversational pace is too hard. As I round the corner to my second trimester, my blood volume will continue to increase and my heart rate may in fact decrease, but that certainly doesn’t mean I’ll be running any faster. Incredibly, by the last few weeks of a pregnancy I will have 30 percent greater aerobic capacity than I normally do. Some credit elite women’s amazing post-partum comebacks to this incredible jump in aerobic capacity brought about by carrying a little person inside you.
Another myth that I was confused about was whether I should do any abdominal exercises while pregnant. I must admit it seemed kind of pointless to do ab work when my belly was going to swell to the size of a basketball in a few months, but I have since learned the error of my seemingly logical reasoning. While ACOG’s guidelines recommend that you avoid doing any exercises on your back after the first semester, it is in fact important to continue to work on your core and that much talked about pelvic floor during pregnancy. Not only will it improve your posture as you get bigger and help prevent back pain, but having a strong core will help when it comes time to deliver, and in recovery as well. Having a strong pelvic floor (the bottom of your core) is especially important for incontinence and postpartum issues.
The take from all of this for me is this: just because you see your toes doesn’t mean you shouldn’t work on your core, and just because you can’t push yourself to your limit while your pregnant doesn’t mean you should throw in the towel. The payoff at the end is worth it: a hopefully quicker recovery, a renewed desire to push yourself to the next level in your sport and an increased aerobic capacity (at least for a little while), not to mention an amazing little bundle that has stolen your heart – and makes your heart rate soar in ways you never knew possible.
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