Gardening, swimming, hiking, fishing: Summer is synonymous with outdoor fun. It can be easy to lose track of time when you’re enjoying yourself, but too many hours in the hot sun can lead to heat-related illnesses. Visits to ERs across the United States for heat exhaustion and heatstroke have increased 3% annually over the past decade and topped 67,500 in 2022, with an average of 702 deaths a year from heatstroke. This makes heat the leading cause of weather-related deaths, beating out cold, hurricanes, and flooding.
Summer temperatures are rising across the nation. The most dramatic example is Arizona, where residents of Phoenix have spent nearly three weeks with temperatures of 110 or higher. In the Hudson Valley, temperatures are 3 degrees hotter on average than in 1970 and are expected to continue rising. With extreme heat events becoming more frequent and intense, it’s important to learn how to keep cool.
A combination of air temperature and relative humidity make up the “heat index,” a single temperature value that indicates how risky it is to be outside. When it’s hot, we perspire to keep cool, but with high humidity, sweat doesn’t evaporate easily. If the heat index is 91 or higher, one of four common types of heat-related illness can occur, ranging from the mild to the catastrophic: heat rash, heat cramps, heat exhaustion and heatstroke.
Heat rash, or “prickly heat,” is a red, bumpy skin irritation that itches and stings. It occurs when perspiration gets trapped under the skin, blocking the sweat glands. Treating it with cool compresses and rehydration works well, but avoid ointments, which may further impede sweat glands.
Excessive sweating during exercise in high temperatures can result in heat cramps. The perspiration leads to a loss in water and body salts (like sodium and potassium), causing severe charley horses. What to do? Rest, replenish fluids and electrolytes with fruit juice, coconut water or sports drinks, and use massage to alleviate the muscle spasms.
Heat exhaustion can occur if you spend too many hours outside when the heat index is high and you fail to drink enough. In these cases, your body temperature may rise to as much as 104 degrees. This high core temperature is called hyperthermia. Symptoms include heavy sweating, rapid breathing, and a fast, weak pulse. You can think clearly, but may experience headaches and dizziness. Treat heat exhaustion by rehydrating and cooling down. Get into an air-conditioned space, take a cool shower, or spritz your skin with cold water and sit in front of a fan. Contact your healthcare provider if your symptoms don’t clearly improve within 30 minutes.
If heat exhaustion goes untreated, it can progress to heatstroke, in which a person’s body temperature suddenly rises above 104 degrees. The skin becomes dry and red, sweating ceases and the victim suffers confusion or may even lose consciousness. If not treated urgently, heatstroke can lead to permanent brain damage, organ failure or death. It is a true emergency, requiring attention within 30 minutes of the onset of symptoms. First, call 911. Then elevate the victim’s feet, apply cool compresses to the skin and loosen their clothing. Do not give fluids, as they may cause choking in a semiconscious victim.
Those at highest risk for heat-related illness include children under the age of 4, adults over 65 and people with outdoor jobs or pastimes, such as farmers, athletes, landscapers, and construction and utility workers. Other risk factors include obesity, medications such as water pills and beta blockers, and health issues like diabetes, chronic kidney disease and heart problems.
Heat-related illness is preventable. Consider acclimating yourself to hot weather: Start with 15 minutes outdoors, then build up your daily exposure. Avoid outdoor activities if the heat index is high. For people that must be in the heat because of work or other obligations, drinking water or fluids with electrolytes every 15 minutes, even if not thirsty, will minimize risk. Take breaks regularly and rest in the shade or AC. Wear loose, lightweight clothing and a hat for sun protection. Use sunscreen: Sunburn impairs the ability to lower body temperature. Alcohol and caffeine both act as diuretics and should be avoided.
If you live in a home without AC or fans, limit your use of the oven and keep shades and curtains closed during the hottest part of the day. Go to the movies, a friend’s house, or a library or community center with air conditioning. Parents and caregivers to small children, elders and pets must remember never to leave them in a parked car when it’s hot outside. Even with a window cracked, it can be deadly.
Mary Jenkins recently retired after nearly 40 years as a family practice physician in New York state.