As summer temperatures rise to the triple digits, so does the challenge of maintaining safe exercise routines. Dr. Jeffrey S. Lander, a board-certified cardiologist with RWJBarnabas Health who specializes in sports cardiology, emphasizes the importance of understanding how heat affects the heart during exercise — and shares vital strategies to ensure heart health during the hot months.
“Exercising in hot weather increases the stress on your heart and body,” says Dr. Lander. “The combined effect of heat and exercise can dramatically increase heart rate and decrease blood pressure, leading to quicker fatigue and potential risks like heat exhaustion or even heat stroke.”
This is due to the body’s natural cooling mechanisms, which require significant cardiovascular effort. When temperatures rise, the human body works harder to cool down, primarily through increased blood flow to the skin and sweat production. High humidity further complicates this because it slows the evaporation of sweat — the body’s method of cooling itself — forcing the heart to work even harder.
To stay safe while exercising in the heat, Dr. Lander recommends several strategies. “Start by gradually increasing the duration and intensity of your workouts in the heat, preferably in consultation with your doctor,” advises Dr. Lander. “This helps your body adapt to higher temperatures and reduces the risk of heat-related illnesses. Check the weather forecast before planning outdoor activities, and consider an indoor workout, or adjusting workout times to the cooler portions of the day, such as early morning or evening when the temperature drops, if the heat index is 95 degrees or higher.” Additionally, Dr. Lander recommends taking frequent breaks to help cool down.
Swimming or water aerobics are excellent alternatives to land-based workouts in the summer. “Water cools your body while reducing impact on the joints,” said Dr. Lander, who added that exercising in cool water may help better manage the heat.
“Maintaining electrolyte balance is also key during summer,” Dr. Lander adds. He recommends consuming beverages with electrolytes during long sessions of physical activity, which can be defined as exercise lasting longer than 90 minutes, to replace the salts lost through sweat.
Dr. Lander also recommends using a smart watch or similar device to monitor one’s heart rate during exercise, explaining that it’s important to stay within 70 to 85 percent of one’s recommended maximum heart rate during hot weather to avoid overburdening the heart.
Especially for individuals with known cardiovascular conditions, Dr. Lander stresses the importance of consulting a healthcare provider before initiating any summer exercise regimen. “Adjusting medication timings or dosages might be necessary to accommodate the increased cardiovascular demands of summer heat,” he notes.
As people embrace more outdoor activities — whether it’s hiking, cycling, or playing sports — it’s important to take these preventive steps to maintain a healthy heart and ensure overall well-being. “This summer, preparation is the best protection against the heat,” Dr. Lander says. “Planning wisely, staying hydrated, and listening to your body can help you and your loved ones enjoy a fun, heart-healthy summer.”