Considerations for Exercising in the Heat

By Hilary Sharp

The Ohio Valley area is known for many great things, including its delicious barbeque, stirring bluegrass music, and warm hospitality. A type of warmth that’s just as familiar is the sticky, humid summer season. Usually lasting from June to late September, the summer brings longer days for family gatherings and outdoor activities. Time spent outdoors is rewarding and beneficial for anyone in the area, but special considerations must be made for those engaging in vigorous physical activity. The high temperatures and humidity can make anyone susceptible to heat-related illness, from the seasoned athlete to the casual neighborhood walker.

During exercise, it is normal for the body's internal temperature to rise between 2-3 degrees Fahrenheit. The strain put on the cardiovascular system induces changes in blood pressure, breathing rate, and cellular metabolism. These functions are routine and expected during regular exercise; they only become abnormal or dangerous when the body cannot cool itself and return to its baseline. When the ambient temperature of the air exceeds 100 degrees Fahrenheit, it becomes much harder to cool the body effectively by sweating alone. Humidity can compound this effect, as the extra moisture in the air further prevents the evaporation of sweat from the skin.

The symptoms of heat-related illness vary during the different stages. The first stage, heat exhaustion, often presents with lower blood pressure, nausea, dizziness and weakness, and cold or clammy skin. This stage of illness is most often managed by moving out of the heat into a cooler and well-ventilated area, stopping exercise activity, and drinking fluids. If treated promptly, there should be no adverse effects from incurring heat exhaustion. The more severe stage of illness, heat stroke, often requires immediate medical attention and can be life-threatening. The symptoms of heat stroke include hot and dry skin with a bright red color, labored breathing, and body temperature above 104 degrees Fahrenheit. These symptoms indicate that the body will not be able to lower its temperature, and the person can be at risk for long-term effects, including damage to the heart and brain. Individuals suspected of suffering from heat stroke should be taken indoors immediately, and their body cooled through any means possible (ice packs, alcohol rubs, wet towels). They should also be transported to an emergency room as soon as possible for treatment.

Taking precautions before exercising can significantly reduce or prevent the likelihood of heat-related illness. Choosing the proper clothing is a requirement often overlooked by people spending long periods outdoors. It is not enough to choose garments with a shorter length; their composition is just as important. Fabrics that cannot wick away sweat prevent the body from cooling itself and trap moisture against the skin. Fabrics like cotton will wick sweat away and allow for quick evaporation. Other synthetic fabrics like polyester offer the same quick-drying characteristics but are not as naturally breathable. Tighter woven materials like denim, nylon, and acrylic will not allow airflow to the skin and are not ideal choices for hot and humid weather.

In addition to choosing the correct clothing, those exercising can help offset the effects of the heat by gradually acclimating themselves to the environment. As the temperature rises, spending a small part of your day outdoors allows your body to experience the effects of the heat without a large amount of stress. Increasing the time increments slowly over 7-10 days will allow your body to build resistance to the increase in temperature and humidity. Drinking the correct amount of fluids is also essential, with the most common recommendation being 8-12 ounces of fluid at least 2 hours before starting exercise. As you sweat, your body loses both water and electrolytes, minerals that are essential to your body's regulatory function. Replacing both during and after exercise is a priority for anyone outside and sweating profusely. Drinking enough water to ease thirst and eating a salty snack should be enough for most people exercising and sweating moderately. Those spending long hours working out or completing strenuous exercises should consult a physician to determine their specific replenishment needs.

The height of the summer season brings so many opportunities for outdoor fun and adventure; be sure to enjoy every event on your schedule safely. Remembering the previous guidelines will help to ensure the prevention of heat-related illness. Keep dry, keep cool and keep hydrated!

Hilary Sharp is a Certified Personal Trainer at the Owensboro Health Healthpark.