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ObGyn/Pregnancy issues/overheated during a very very hot run at 4 weeks before I knew I was pregnant


A week ago, before I knew I was pregnant (I am now a little over 5 weeks), I went on a run in the middle of a sunny day in very hot weather (90 degrees) for about 45 minutes.  I was quite thirsty at the end and pushed myself hard up to the very end, in large part because the hot water was out in our apartment and, as a person who generally hates cold showers, I wanted to be able to "comfortably" take a cold shower.  Stupid now, I know! As soon as I got back to our apartment, I drank a full bottle of water immediately and hopped into a cold shower. I didn't feel sick or dizzy, just very very hot and very very thirsty.  Three days later, I found out I was 5 weeks pregnant, and I've only now learned about the no-overheating rule and I am desperately scared that I have caused birth defects to my baby.  Do you think that's the case?

I generally do cardio 2-3 days a week, strength training 3 days a week, so I'm not new to exercising, but this has me freaked out that I should not even use the elliptical machine at the gym!  Please let me know what you think. I'm beating myself up for possibly harming my baby.  

Thank you for your help.

While your core temperature might have risen a few degrees, birth defects have been found when core temperature rises quite high, over 102 degrees. This generally occurs with high fever, or prolonged use of a sauna or hot tub. In all but the most extreme cases, exercise does not raise core temperature to rise to that extreme. If it did, you would have felt extremely ill, and most likely would have been vomiting.
So a bit scary, yes, but you can relax and not worry that you've comprised your pregnancy in any way.
Keep up your high fitness level, as fetal health directly corresponds to maternal health. Take you runs in the morning, drink lots of water, and always workout in a zone that you perceive is "somewhat" difficult.
At about 20 weeks, start to taper down the intensity of your workouts.

ObGyn/Pregnancy issues

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Helene Byrne


I can answer all questions regarding prenatal and postpartum fitness and exercise. I will not answer any questions that are not related to prenatal and postpartum fitness and exercise. I will not answer questions regarding getting pregnant, or signs or symtoms, only fitness and exercise during and after pregnancy. No due dates, medical problems during pregnancy, signs or symtpoms of pregnancy, pregnancy tests, vaginal problems/smells/discharge, periods or ovulation.


Pre-and-Postnatal Exercise Specialist ACE certified Personal Trainer Author: "Exercise After Pregnancy: How to Look and Feel Your Best" Book Author: "Bounce Back Fast! Post Natal Core Conditioning" DVD Founder: BeFit-Mom Teacher: Post Pregnancy Exercise Workshops

IDEA Health and Fitness Association

numerous regional parenting magazine

Dancing Thru Pregnancy, Pre/Post Natal Exercise Specialist Certification 2000 Resist-a-Ball Core Program, 1999 American Council on Exercise, Personal Trainer Certificate, 1999 Peak Performance, San Francisco, CA, Pilates Instructor Training Program, 1992 Health and Fitness Institute, Cal State Hayward, Personal Trainer Certificate, 1990 American College of Sports Medicine, Group Exercise Leader, 1989 Boston Conservatory, BFA/Dance, 1982

Awards and Honors
´┐ŻBounce Back Fast! Post Natal Core Conditioning´┐Ż, 2005. Winner of the Platinum Award from the Family Review Center, 2007.

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