Pregnancy & Baby Index: Pregnancy - Fitness: Running during pregnancy and your heartrate

Running during pregnancy and your heartrate

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Lisa Stone

If you're a runner, do you need to stay below a 160 bpm heart rate during pregnancy? Lisa Stone, an ACE-certified Pre-and Post-Natal Fitness Instructor, presents some points for you discuss with your caregiver.

Your question
I have been getting conflicting information regarding the appropriate heart rate when running. I currently am 9 weeks pregnant and when running my heart rate ranges between 150 bpm and 160 bpm. After 15 minutes I stop and let my heart rate drop to below 140 for 5 minutes, then I continue running for 15 minutes. I find it almost impossible to run with my heart rate under 140 bpm. What is safe? Is it necessary to stop during a 30/40 minute run? I feel great during my runs and never get totally exhausted. Please help, I am completely frustrated. - Raquel, Buffalo

The expert answers
With your caregiver's approval, during the remainder of your first trimester, continue running at your pre-pregnancy pace, ignore your heartrate, and just make sure to drink LOTS of water before and after each run to stay well-hydrated and to keep your core temperature within a safe range. If you start to feel dizzy, lightheaded, or nauseous, you're working too hard and need to slow down your pace and/or shorten the distance you're running.

After the first trimester, you may need to slow down a bit due to the discomfort caused by bouncing belly and breasts. At this point, supportive workout wear, like Mothers In Motion, may be a good investment. If you're at risk for preterm labor, you may need to switch to power walking or some other aerobic activity to prevent your growing uterus from putting too much pressure on your cervix.

During the third trimester, running may just be too uncomfortable. If so, consider trying something new like swimming, biking, step aerobics, or water aerobics. If running is still okay for you, go for it! Just be very aware of your changing center of gravity (loss of balance could be a problem if you run on uneven pavement) and loosening joints.

Notice that I didn't even mention heartrate? It really isn't an accurate measure of exertion level during pregnancy. It's much better if you really tune into your body's signals as to when you're working too hard or not hard enough.

Hope this helps to clarify things for you!

Lisa :)