Keep exercising this summer… without letting the heat stop you

• Exercising in the heat calls for precautions: specialists explain how to keep up your routine in summer and which signs of overheating should never be ignored.

With the arrival of summer and rising temperatures, many people wonder whether it is sensible to keep up their exercise routines when it is very hot. The Dominican Institute of Meteorology (INDOMET) has warned that the heatwave affecting the country could keep temperatures high in some regions.

While physical exercise is essential for cardiovascular, muscular and emotional health, doing it in extreme heat can become a serious risk if the proper precautions are not taken. Whether you exercise indoors, train in a park or cycle along trails, overheating is a real possibility. Even experienced athletes in excellent physical condition need a clear plan to prevent heat-related illness and to know the warning signs that must not be ignored.

“Your body is designed to regulate its own temperature during exercise. But when we train in a hotter environment, it has to work much harder to do so”, explains Dr Sarah Eby, MD, PhD, a sports medicine specialist at Mass General Brigham and the Spaulding Rehabilitation Network. She adds that “heat tolerance varies from person to person, and the body needs to adapt gradually in order to tolerate physical activity in these conditions. That is why it is essential to start with gentle sessions, build up the intensity gradually and pay close attention to the signals the body sends us”.

Exercising in the heat: what your body is trying to tell you

Exercising on hot days is not necessarily dangerous, but it does require attention. When the thermometer rises, your body is forced to work harder to stay cool. Certain precautions are therefore needed when exercising —good hydration and well-timed breaks, for example— to prevent what specialists call heat-related illness. In simple terms, these are signs that the body is struggling to regulate itself.

“Prolonged exposure to heat, combined with physical effort, causes excessive sweating and the loss of fluids and salts, and that can throw the body out of balance”, explains Dr Eby. “Basically, your body is asking you to stop and help it cool down”, she says.

Heat-related illnesses range from mild discomfort to medical emergencies. Knowing them and being able to identify them can make a great difference:

• Heat cramps: these usually appear in the legs or abdomen, the result of exertion and the loss of electrolytes.
• Heat exhaustion: this shows up as heavy sweating, clammy skin, weakness, dizziness and nausea. It is a clear sign that you must stop and rehydrate.
• Heatstroke: the most serious of all. It occurs when body temperature goes above 40 °C. It can be life-threatening and requires immediate medical attention.

Too hot while training? Here is what to do if your body overheats

You are in the middle of an outdoor routine, sweating like never before, and suddenly you do not feel well: dizziness, weakness, nausea, cramps… Your body is trying to tell you something clear: it needs you to stop. When the first signs of overheating appear, there is no time to wait. Acting promptly can prevent serious consequences. Dr Sarah Eby recommends a few key steps:

• Get out of the sun immediately or find a cool, shaded spot.
• Take off unnecessary clothing to help your body release heat.
• Rest without pushing your body any further.
• Hydrate with water or sports drinks (avoid salt tablets, as they can make dehydration worse).
• Cool your skin with room-temperature water and fan yourself. Avoid dousing yourself suddenly with very cold water, as that can disrupt the body’s natural regulation.

According to Dr Eby, there are signs that should not be ignored and that require immediate medical attention, such as fever or a raised body temperature, fainting, vomiting or a lack of improvement after an hour of rest and hydration.

Prevention is better than regret: what to consider when exercising in hot weather

The most effective way to avoid heat-related illness is to plan ahead. Dr Eby offers several recommendations for athletes of all levels, highlighting constant hydration as the key factor. “Many athletes think they can manage without water, but that is a common mistake. Constant hydration is one of the main precautions when exercising, because it is vital for performance and, above all, for health”, she says.

She and the American Council on Exercise suggest the following hydration plan:

• Several hours before exercise: 17 to 20 ounces of water
• 20 to 30 minutes before exercise or during the warm-up: 8 ounces of water
• Every 15 to 20 minutes during exercise: 4 to 8 ounces of fluid

Other important recommendations for exercising in hot weather:

• Avoid the hottest hours (between 11 a.m. and 4 p.m.); choose mornings or evenings.
• Wear light, light-coloured clothing that breathes well.
• Pace yourself. Start slowly and let your body adapt before increasing the intensity.
• Train with someone. A partner can help you watch for warning signs.
• Look for shade and take frequent breaks. A rest under a tree or a canopy can make all the difference.
• Use sunscreen. Burns damage the skin and make it harder for the body to cool down properly.

The specialist also recommends using the heat index to understand better how the body perceives temperature. This index takes into account both temperature and humidity, and can be useful for setting guidelines for physical activity.

“It is important to bear in mind that the heat index is also calculated for the shade”, explains Dr Eby. “That means that if you train in the sun, your body will feel much hotter than the figure suggests. So before exercising, check the heat index, adapt your routine if necessary and, afterwards, think about how you felt. That experience will help you make better decisions the next time you train in hot weather”.

There is no doubt that you do not have to stop exercising when it is hot, but you do need to be more aware. Moving is health, but moving intelligently is wellbeing. Do you want to keep training this summer? Do it, but listen to your body. It always knows when it is time to ease off.