Experiencing a Heatwave? Exercise with Caution

heatwave exercise

Heatwaves are more than just another hot day – they can be deadly when combined with exercise.

A recent study reveals the physiological strain that even moderate heat and light exercise can place on the human heart.

Published in the Journal of Applied Physiology by scientists from Pennsylvania State University (Penn State), this study involved 51 healthy young volunteers who were asked to engage in light physical activity inside an environmental chamber. The temperature or humidity in this chamber increased incrementally every five minutes, closely simulating a heatwave environment.

Using ingestible sensors, researchers monitored the participants’ core temperature and heart rate, revealing that a rise in heart rate actually precedes an increase in body temperature. This early sign of strain to the heart is critically important to recognize for fitness enthusiasts and athletes who frequently work out in challenging weather conditions.

The Hidden Risks of Cardiovascular Strain

Cardiovascular strain, often unnoticed due to lack of immediate discomfort or pain, can lead to various health complications, including heart disease, stroke, and kidney damage.

The research from Penn State also unveiled that cardiovascular strain occurs even during slow walking/ low intensity exercise in humid conditions of around 34 degrees Celsius, and the risk is elevated significantly for those engaging in high-intensity workouts in the same conditions.

Rethinking Workout Routines and Strategies

With the rising frequency of heatwaves around the world, a reassessment of workout routines and strategies is essential, particularly for outdoor exercise.

It is important to modify the intensity and duration of workouts, maintain hydration, ensure adequate rest periods, and monitor heart rate. Using smart devices for heart rate monitoring can also act as an early warning system to prevent serious health risks.

Tips and Precautions:

Schedule Your Workouts

Plan your exercise routine early in the morning or late in the evening when temperatures are lower. This not only reduces heat exposure but also helps maintain a safe heart rate during exercise.

Choose Your Outfit Wisely

Light, breathable clothing can help keep your body cool during a workout. Protect your skin with a hat and sunscreen, and ensure you stay hydrated with a water bottle.

Adjust Workout Intensity

The intensity of your exercise can contribute to an increased heart rate and core body temperature. Make adjustments based on the day’s temperature and humidity levels.

Consider Indoor Exercise

When temperatures are high, moving your workout indoors to an air-conditioned environment can offer a safer alternative.

Maintain Hydration

Drinking water before, during, and after your workouts is crucial during heatwaves. Avoid alcohol, caffeine, or high-sugar drinks, which can exacerbate dehydration.

Adjust Your Diet

Eating smaller, frequent meals and including cold foods like salads and fruit can help keep your body cool.

Listen to Your Body

If you notice a sudden increase in heart rate, take a break, cool down, and hydrate. Your body’s signals are essential in preventing heat-related health complications.

The Dangers of Exercising in Heat

The human body has an incredible ability to maintain an optimal internal temperature, but that ability comes at a cost.

As our bodies strive to regulate heat during a heatwave, the blood vessels dilate and sweating increases, which can cause a reduction in blood pressure and increased cardiac demand. This often leads to mild symptoms like a heat rash or swelling, and in severe cases, heat exhaustion and increased risk of cardiac events.

That means that exercising in a heatwave can expose the body to dual stresses: the physical exertion from the exercise and external heat. This combination can overwhelm cooling mechanisms inside the body, causing a dangerous increase in heart rate and core body temperature.

Another risk that arises from exercising in heat, is that when a person is overly focused on the results of a workout, this can overshadow initial, subtle signs of heat strain, leading to delayed intervention and increasing the risk of more serious health complications. Therefor if you really must exercise in a heatwave, keep an eye on your vitals to ensure your safety and minimise the risk of heat-related health problems.

A Greater Warning for the Planet

As heatwaves increase in frequency and severity due to climate change, so too does the risk to human health and wellbeing.

Our actions to protect ourselves while exercising during heatwaves are but one facet of a much larger issue at hand.

Global action is urgently needed to reduce greenhouse gas emissions drastically, according to many scientific studies. Our current path will lead to “continuous thermal stress,” as the biosphere shrinks under rising temperatures. This grim scenario would have far-reaching implications for all life on Earth – not just humans. 

Each one of us has a role to play in looking after our planet, whether it’s adapting our behaviors to live more sustainably, advocating for stronger environmental policies, planting more trees, or educating others about climate issues.



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