As the World Cup begins in the US, Canada and Mexico, scientists have predicted that extreme heat could play a decisive role in determining the outcome.
almost half the scheduled matches There is at least a 50% chance of “performance-destroying heat” – especially in the more southern regions of the US and low-lying parts of Mexico. Many teams to prepare undergoing intense training in hot conditionsAnd during the tournament, they will have access to cold-water immersion tubs, ice jackets and misting fans to help players cool off if they overheat.
Compared to these major sporting events, which have resources to adapt to extreme heat, community sport participants and recreational practitioners often have fewer options. This lack of adaptability can increasingly impact when, where, and how people can exercise safely, especially when Climate change creates extreme heating events more frequent and intense.
“Most people who play sports for competition or simply for fun, enjoyment and leisure have a degree of that power [of professional sports organizers] But face great challenges and losses,” jessica murfreyAn assistant professor in the department of exercise and sport science at the University of North Carolina at Chapel Hill told Live Science.
How hot is too hot to exercise?
Sports governing bodies commonly use Wet-bulb globe temperature (WBGT) to assess heat risk. It measures the combined effects of temperature, humidity, direct sunlight and wind speed on the human body.
It’s important to take humidity into account because, with more water in the air, it is harder for sweat to evaporate from the skin and cool the body. wbgt was Developed by the US Army in the 1950s To prevent heat-related deaths in training camps. Nowadays, it produces safety guidelines for outdoor workers as well as athletes.
American College of Sports Medicine Divides the US into three regions to take into account different levels of heat adaptation and defines WBGT categories that pose a “very high” risk in each region. The range is a WBGT of 82.2 °F (27.9 °C) or higher in the southeastern and southwestern states, 79.9 °F (26.6 °C) in the central states, and 76.3 °F (24.6 °C) in the northern regions.
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For habitual individuals and those with poor physical fitness, the health risk reaches a low threshold.
The Gulf Coast states – especially southern Texas, Louisiana, Mississippi, Alabama, and Florida – Experience the highest WBGT values. High risk conditions begin in May in South Texas and South Florida, before moving northward and peaking in July and August. Studies show that the number of extreme humid heat events has increased more than double Climate change has increased across much of the US, and globally, since the 1980s. Nearly three weeks of dangerously humid heat Alone in 2024.
Average monthly WBGT in the Southeastern United States between 1991 and 2020.
A person’s overall health and fitness, hydration levels and amount of exertion need to be considered, Murphree said, and systemic factors like socioeconomic status also come into play. For example, low-income families are More likely to live in hot urban environments And Lack of access to air conditioningWhich means they may already be experiencing heat stress at home.
While sweat cannot evaporate easily due to high humidity and heat, the body has other means of cooling down. It also sends more blood to the skin, arms and legs, allowing heat to escape through the skin. But physical exertion in extreme heat makes it more difficult.
“We only have a limited amount of blood in our bodies, and we’re trying to use it to promote responses in our muscles to be able to facilitate exercise, as well as send it to our skin to help cool us down,” he said. grant lynchA research fellow at the Heat and Health Research Center at the University of Sydney.
When the body can’t get rid of excess heat, symptoms of heat exhaustion – including dizziness, nausea, headache and muscle cramps – may begin. If the body continues to overheat, it can turn into heat stroke, a serious and potentially fatal medical emergency where a person’s core body temperature rises to 104 F (40 C) or above. Heat stroke can cause central nervous system dysfunction delirium, convulsions or coma.
In America, extreme heat stroke is a leading cause of preventable death during sports and exercise and have a Special concern for young athletes. children including teenagers, produce more heat relative to their body weight Sweat less than adults. Additionally, if they start feeling sick they may feel less able to advocate for themselves on the playing field, Murphree said.
Heat can be especially dangerous for children and teens compared to adults.
(Image credit: Farazao Studio Latino via Getty Images)
Reducing health risks in hot weather
The body can tolerate extreme heat to some extent. At the University of Sydney’s Thermal Ergonomics Laboratory, researchers use a climate chamber to test the body’s ability to adapt by increasing blood plasma volume and reducing heart rate and resting temperature.
“We’ll have them go through five to 14 consecutive days of exposure,” Lynch said. “They will cycle or run for between 90 minutes to 2 hours every day, and the conditions will also be [95 F to 104 F] Keep the temperature in the room at 35 C to 40 C for that entire period.”
The benefits obtained through this type of thermal adaptation are not permanent. Research shows that, for every two days spent in a cold environment, A day lost in thermal acclimation. “For people who exercise only a few times a week in hot weather, it’s very unlikely that you are as physically adapted as you think,” Lynch said.
While WBGT is considered The “gold standard” for heat safety monitoring.The specialized equipment needed to measure this may not be available to every community sports organization or individual exercising. The danger, Lynch said, is that many people focus only on ambient temperature to determine risk, when many factors are involved and can be complex.
Sports Medicine Australia, the country’s national body for sports medicine and sports science, developed a device To calculate risk and suggest safety precautions. It combines data automatically extracted from weather stations – including ambient temperature, humidity, wind speed and solar radiation – with sport-specific information, such as specific uniforms and duration of activity.
In general, sports organizations recommend staying hydrated before, during, and after physical activity; wearing light and breathable clothing; using ice towels and misting fans to rest frequently when possible; and delaying or canceling games when the risk level becomes too high. If someone begins to feel extreme heat, immediate action is important to prevent further heat stress.
“Without a doubt the most important thing to do is to stop or reduce the intensity of the activity you’re doing, seek shade, move to an area where you’re not exposed to direct sunlight, and then wash the skin with water,” Lynch said.
Heavy sweating, painful muscle cramps, nausea, dizziness, and cold, pale, clammy skin occur all signs That a person may suffer from heat-related illness. Heat Stroke Symptoms involve very high temperatures; hot, dry skin or excessive sweating; Confusion; and loss of consciousness. These symptoms should be treated immediately with a cold shower and emergency medical care.
While rescheduling events to cooler parts of the day is one option, Heat wave is already increasing in most areas And this trajectory is expected to continue as average global temperatures increase. Therefore, some researchers and sports organizations are exploring changes to infrastructure that could help: stadiums with shady and green spaces, Schoolyards with grass instead of concreteAnd Artificial Turf with Built-in Irrigation System For use in school play areas.
Murphree said she would like to introduce heat safety training in schools in areas with extreme heat in the US, similar to existing fire safety education.
“Sports often asks us to push ourselves harder, to become faster and stronger,” Murphree said. “It’s okay to take breaks, stop, slow down, reschedule, and advocate for our bodies and our health over the summer.”
This article is for informational purposes only and is not intended to provide medical advice.
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