Q: When there is more moisture in the air, should I worry about hydration?

A: It is easy to assume that the risk for dehydration and other heat-related illnesses, such as heat stroke, decreases when it’s humid outside. However, the risk for dehydration actually increases when the air is full of moisture.

When the weather is humid, sweat cannot evaporate and cool you down as quickly as it normally does. This can increase body temperature and require you to drink more fluids. When the summer heat is drier and less humid, the moisture on the skin will evaporate quickly, cooling down the body temperature.

Whether the air is humid or dry during the summer, staying hydrated is essential. To prevent dehydration and other heat-related illnesses, drink plenty of water or eat foods with high water content before exercising or doing physical activity in the heat. Be aware that dehydration can also occur in colder temperatures when wearing insulated clothing or when spending too much time in a heated, indoor space.

If you start to feel dehydrated during exercise, find a shaded area if you are outside, recline and drink water or a sports drink. It’s important that everyone, especially athletes are aware of the symptoms of dehydration as we approach summer, which include dry mouth, sleepiness or tiredness, thirst, dry skin, decreased urine output, headache and dizziness.

Dr. Appathurai Balamurugan is chief resident in the Department of Family and Preventive Medicine in the College of Medicine at the University of Arkansas for Medical Sciences. Email your health questions to housecall@uams.edu.