Tips for Pregnant Runners

It wasn't long ago that women were strictly forbidden from running while pregnant out of fear that the fetus would be harmed because of a decrease in oxygen and blood flow to the uterus. Recent research not only proved those fears untrue, but found that rigorous exercise during pregnancy is safe and beneficial to mother and baby.

One study even found that at age 5, children of mothers who did vigorous exercise during pregnancy, including running, scored higher on tests of intelligence, coordination and language skills, compared to mothers whose only exercise during pregnancy was walking.

Dr. Robert Sallis, co-director of Sports Medicine Fellowship at Kaiser Permanente Fontana Medical Center and spokesperson for the American College of Sports Medicine said he can't emphasize enough what a positive thing it is for women to run while pregnant.

"My patients who run during pregnancy gain less weight, feel better overall, have an easier labor, less postpartum depression and fewer postpartum problems," he said.

That's Fit spoke to Sallis for his best advice for women who want to run while pregnant.

1. You can start exercising now. Though conventional wisdom has said you shouldn't start an exercise program when you're pregnant, Sallis argues the opposite. "Women are often much more open to change and focused on health when they are pregnant and it's a great time to begin exercising as long as you start slow and gradually build up from there," he said.

2. You don't have to scale back. "In most cases, women can maintain the same routine and gradually back off as they get bigger and become more uncomfortable," Sallis said. "But there's no need to decrease your intensity in the first trimesters."

3. Be cautious about heat and humidity. There's no reason that pregnant women are more prone to heat stroke than nonpregnant women. Like all runners, pregnant women should drink more fluids and pay attention to dizziness and other signs of heat exhaustion, Sallis said.

4. Choose even ground. "One of the biggest issues with running while pregnant is balance," he said. "Particularly as you get further along, running on flat, level surfaces becomes more important."

5. Don't drink too much or too little. How much you need to drink while running is very individual. Ideally, a runner will have an idea of her sweat rate, said Sallis. The best way to gauge your sweat rate is to weigh yourself nude before you run, don't consume anything during the run and weigh yourself nude after. The weight loss represents sweat loss and the amount of fluid that needs to be replaced. But a general guideline is too look at your urine. It should be a pale lemonade color. If it's very dark, you're dehydrated and if it's always clear, you're drinking too much water.

6. Wear stable shoes. A major concern for pregnant runners is the elasticity of muscles caused by a pregnancy hormone, relaxin. "Coupled with the balance issue, muscle elasticity makes stable shoes very important to prevent injuries. I generally tell patients that when they find running shoes that work, to stick with them," he said. "So if you have a shoe that works, there's no need to find a stability shoe because you're pregnant. However, I would advise against shoes that have a rocker in the bottom and I would be very concerned about barefoot running shoes."

Read about a woman who ran three marathons while pregnant.