Running During Pregnancy: A Guide to Half Marathon Training

Question
Hi,

Over the past 3 1/2 months I have been running consistently about 4-6.4 miles, 5-6 days per week. I run at a pace that is comfortable for me as I'm not necessarily running to be competitive, but because I enjoy it. I've also enjoyed setting goals to keep me motivated -- I finished my first 10k about a month ago, I have another 10k this coming weekend, and I'm training for the Seattle 1/2 Marathon which is in about 8 weeks.

However, I've just found out I'm 5 weeks pregnant (we were trying so it was great news!) So, now that I'm pregnant again I'm wondering if I can continue training for the 1/2 Marathon or if I should simply maintain the level I'm running at now? Will training for the 1/2 Marathon have a negative effect on my baby?

Thank you!

Cheryl

Answer
Generally, healthy women can maintain their fitness levels, both in time and intensity, in the first half of pregnancy. Since you are well acclimated to running, you are not overly stressing your system at the pace and distance that you have been doing.

As to possible negative effects, there has been one study - and I want to stress only one study - that found a correlation between high intensity/high impact/and high volume exercise and miscarriage in the first trimester. But the study did not look at factors such as previous fitness level, nutrition prior to and during pregnancy, lean body mass, age, history of miscarriage, etc. And since no other study to date has corroborated these findings, it's not yet possible to come to a clear conclusion.

All other previous studies did not find a link between pregnancy exercise and miscarriage or other negative outcomes. In fact the opposite is true, maternal exercise has been shown to overwhelmingly reduce all types of pregnancy complications.

So my advice to you is to stay within your comfort zone, both physically and psychologically. If this weekend's 10K will cause you a lot of worry and anxiety, don't do it. If you decide to participate, stay well hydrated, and carbo-load before the event so you'll be topped off nutritionally. If the weather is not ideal, you might want to reconsider, as pregnancy causes increased maternal heat, and you will feel the heat much more intensely than before your pregnancy.

I think that maintaining your running time/intensity, rather than gearing up for a 1/2 marathon, is the best choice. Maybe you can find another 5K to 10K fun run to substitute.

For more details on aerobic exercise during pregnancy adn how to modify your workouts as pregnancy progresses, go to: http://www.befitmom.com/aerobic_exercise.html