Exercising in hot and humid weather can be challenging at best and hazardous at worst. Dehydration is a constant concern, and body temperatures can quickly rise from the normal range of 97-99 degrees Fahrenheit to 103 degrees Fahrenheit.

“Extreme summer heat can create unhealthy conditions, and those who exercise outside should take special precautions,” said Dr. Tom Bartsokas, of The Bone & Joint Clinic in Franklin. “Humidity above just 40% contributes to the stress of outside exertion by limiting the evaporation of sweat, which is the main mechanism of body cooling when ambient temperature exceeds 68 degrees Fahrenheit.”

Bartsokas, an avid runner who runs about a thousand miles per year in all types of weather, provided the following tips for exercising in hot weather:

• Because tolerance for heat increases with fitness, it’s important to be in good shape before attempting to exercise in hot and humid weather.

• Exercise in the coolest parts of the day – early morning or in the evening.

• Get acclimated to the hot weather by exercising for shorter periods of time, with less intensity, for at least 1-2 weeks.

• Drink on a schedule, rather than relying on your thirst to tell you when to drink, and favor sports beverages.

• Avoid caffeinated and alcoholic beverages, which promote water loss through urination.

• Wear loose-fitting clothing that allows sweat to evaporate. Light colored clothing made of cotton or sweat-wicking fabrics are best, and a hat with a brim will help shade your face.

• Use a good sunscreen product with an SPF of at least 15.

• Drink two 6-8-ounce cups of water an hour or two before starting to exercise.

• During exercise, drink 6-8 ounces of fluids every 15-20 minutes.

• When finished, stretch in a shaded or cool area, and drink fluids to help replace water lost.

• Do not take a hot bath or shower, or go into a sauna, immediately after exercising, as the heat can suddenly lower blood pressure and increase the risk of fainting or a heart attack.

Bartsokas also noted that it is important to recognize heat-related illnesses:

Heat cramps are intense, painful muscle spasms that usually affect those muscles more heavily involved in activity. They typically occur toward the end of an exercise period or even 6-12 hours later. If you develop a heat cramp, stop exercising immediately, rest and drink fluids. Massaging sore muscles may help relieve some of the pain.

Heat exhaustion is characterized by weakness, nausea (sometimes with vomiting), shortness of breath, uncoordinated gait, gooseflesh, dizziness, headache and muscle cramps. Individuals suffering from heat exhaustion usually maintain a clear head in spite of not feeling well. If you experience any of these symptoms, try to get to a cool environment immediately. Lie down with your legs elevated, apply ice to your body and drink fluids.

Heat stroke – a life-threatening condition that requires immediate attention – occurs when your body is unable to regulate its own temperature. Symptoms include heat sensations around the head, nausea, dizziness or fainting, paleness, damp or perspiring skin and excessive fatigue. Heat stroke victims also may experience changes in mental perception, such as inability to concentrate, lapses in memory and blurred vision. If you have any of these symptoms, seek medical assistance immediately. In the meantime, rest in a cool area, elevate your legs, drink cool fluids and apply ice to help reduce your body’s temperature.