Summer is a great time for outdoor exercise, but pregnant women need to be especially careful to avoid overheating when the temperature soars. Hot and humid environments may cause dehydration during pregnancy, and in severe cases can lead to premature labor. During the first trimester, sustained bouts of high maternal core temperatures during the use of hot tubs and saunas has been associated with neural tube defects, but exercise in environments that allow for maternal heat regulation has not been shown to increase core temperatures to dangerous levels.
To avoid these concerns, pregnant women should avoid exercising in an environment where they cannot dissipate core heat effectively, (such as high heat index days) the use of saunas or hot tubs, and heated exercise rooms such as those used for hot yoga.
Pregnant women can avoid the risk of overheating during exercise by following these tips:
- Avoid exercising outdoors when the heat index is considered dangerous-check with your local weather report to see what the index is on hot days.
- Exercise in a climate-controlled facility during the hotter and more humid summer months.
- Drink fluids early and often when exercising.
- Monitor hydration level by checking weight before and after exercise and drinking fluids after exercise to regain lost fluid weight.
- Exercise early or late in the day when temperatures are lowest.
- Discontinue exercising if symptoms of overheating occur (lightheadedness, nausea, faintness, excessive sweating, and feeling uncomfortably hot) and move to a cool environment.