<\/p>\n Compared with these major sporting events, which have resources to adapt to extreme heat, community sports participants and recreational exercisers often have fewer options. This lack of adaptability may increasingly affect when, where and how people can safely exercise, especially as climate change<\/a> makes extreme warming events more frequent and intense<\/a>.<\/p>\n “The majority of people who play sport for competition or just for fun, recreation and leisure have a fraction of that power [of professional sports organizers] but face greater challenges and harms,” Jessica Murfree<\/a>, an assistant professor in the Department of Exercise and Sport Science at the University of North Carolina at Chapel Hill, told Live Science.<\/p>\n How hot is too hot for exercise?<\/p>\n Sports governing bodies typically use wet-bulb globe temperature<\/a> (WBGT) to assess heat risk. It measures the combined impacts of temperature, humidity, direct sunlight and wind speed on the human body.<\/p>\n You may like<\/p>\n Taking humidity into account is key because, with more water in the air, it’s harder for sweat to evaporate off the skin and cool the body. WBGT was developed by the U.S. military in the 1950s<\/a> to prevent heat-related deaths in training camps. Nowadays, it also shapes safety guidelines for outdoor workers, as well as athletes.<\/p>\n The American College of Sports Medicine<\/a> divides the U.S. into three regions to account for varying levels of heat acclimatization and defines WBGT ranges that pose a “very high” risk in each region. That threshold is a WBGT of 82.2 degrees Fahrenheit (27.9 degrees Celsius) or higher in Southeastern and Southwestern states, 79.9 F (26.6 C) in Central states, and 76.3 F (24.6 C) in Northern regions.<\/p>\n For unacclimatized individuals and those with poor physical fitness, the health risk jumps at lower thresholds.<\/p>\n Gulf Coast states \u2014 particularly Southern Texas, Louisiana, Mississippi, Alabama and Florida \u2014 tend to experience the highest WBGT values<\/a>. High-risk conditions begin in May in South Texas and South Florida, before expanding northward and peaking in July and August. Studies suggest the number of extreme humid heat events has more than doubled <\/a>in most parts of the U.S. since 1980, and that globally, climate change added roughly three weeks’ worth of dangerous humid heat<\/a> in 2024 alone.<\/p>\n \n Average monthly WBGT in the southeastern United States between 1991 and 2020.<\/p>\n (Image credit: Thompson, D. (2026). Journal of Applied Meteorology and Climatology 65, 3; 10.1175\/JAMC-D-25-0125.1<\/a> \u00a9 American Meteorological Society. Used with permission.)<\/p>\n An individual’s overall health and fitness, hydration levels and amount of exertion need to be considered, and systemic factors like socioeconomic status also come into play, Murfree said. For instance, lower-income families are more likely to live in hotter urban environments<\/a> and lack access to air conditioning<\/a>, meaning they may already be experiencing heat stress at home.<\/p>\n What to read next<\/p>\n While high humidity and heat make it so sweat can’t evaporate easily, the body has other means to cool down. It also sends more blood to the skin, arms and legs, allowing heat to be released through the skin<\/a>. But physical exertion in extreme heat makes this more difficult.<\/p>\n “We only have a limited amount of blood in our body, and we’re simultaneously trying to use it to fuel the reactions in our muscles to be able to facilitate exercise, as well as send it to our skin to help us cool down,” said Grant Lynch<\/a>, a research fellow in the Heat and Health Research Centre at the University of Sydney.<\/p>\n When the body can no longer get rid of extra heat, symptoms of heat exhaustion<\/a> \u202a\u2014\u202c including dizziness, nausea, headache and muscle cramps \u202a\u2014\u202c may set in. If the body continues to overheat, this can progress to 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 and delirium, convulsions or coma<\/a>.<\/p>\n In the U.S., exertional heat stroke is a leading cause of preventable death<\/a> during sport and exercise and is a particular concern for youth athletes<\/a>. Children, including teens, produce more heat relative to their body weight<\/a> than adults do while sweating less. Additionally, they may feel less able to advocate for themselves on the playing field if they start to feel ill, Murfree said.<\/p>\n \n Heat can be especially dangerous for children and teens, compared to adults.<\/p>\n (Image credit: Frazao Studio Latino via Getty Images)<\/p>\n Reducing health risk in hot weather<\/p>\n The body can acclimate to extreme heat, to some extent. At the University of Sydney\u2019s thermal ergonomics laboratory, researchers use a climate chamber to test the body\u2019s capacity to adapt by increasing its blood plasma volume and lowering heart rate and resting temperature.<\/p>\n “We would have them come in for anywhere from five to 14 consecutive days of exposure,” Lynch said. “They would be cycling or running for between 90 minutes to 2 hours every day, and the conditions would be [95 F to 104 F] 35 C to 40 C in the room for that entire duration.”<\/p>\n The benefits achieved through this kind of heat acclimation aren’t permanent. Research suggests that, for every two days spent in a cool environment, one day of heat acclimation is lost<\/a>. For people exercising just a few times a week in hot weather, “it’s pretty unlikely you are physiologically adapting as much as you think you are,” Lynch said.<\/p>\n While WBGT is considered the “gold standard” for heat safety monitoring<\/a>, the special device required to measure it may not be accessible to every community sports organization or individual person exercising. The danger, Lynch said, is that many people focus on ambient temperature alone to determine risk, when multiple factors are involved and can compound.<\/p>\n Sports Medicine Australia, the country’s national body for sports medicine and sports science, developed a tool<\/a> to calculate risk and suggest safety precautions. It combines data automatically extracted from weather stations \u2014 including ambient temperature, humidity, wind speed and solar radiation \u2014 with sport-specific information, such as typical uniforms and duration of activity.<\/p>\n Generally speaking, the sports body recommends staying hydrated before, during and after physical activity; wearing lightweight and breathable clothing; taking frequent rest breaks using ice towels and misting fans when possible; and delaying or cancelling games when the risk level gets too high. If someone begins to feel overheated, immediate action is important to prevent further heat strain.<\/p>\n “The most important thing to do, without a doubt, is to stop or reduce the intensity of the activity you’re performing, seek shade, go into an area where you are not exposed to direct sunlight, and then douse the skin with water,” Lynch said.<\/p>\n Heavy sweating, painful muscle cramps, nausea, dizziness, and cool, pale, clammy skin are all signs<\/a> that someone may be suffering from heat-related illness. Heat stroke symptoms<\/a> include a very high temperature; hot, dry skin or profuse sweating; confusion; and loss of consciousness. These symptoms should prompt immediate cooling with a cold water bath and emergency medical care.<\/p>\n While rescheduling events to cooler parts of the day is an option, heatwaves are already increasing in most regions<\/a> and that trajectory is expected to continue as average global temperatures rise. So, some researchers and sports organizations are exploring infrastructure changes that could help: stadiums with shaded and green spaces, schoolyards with grass instead of concrete<\/a>, and artificial turf with a built-in irrigation system<\/a> for use in school sports fields.<\/p>\n Murfree said she would like to see heat safety training introduced in schools in areas prone to extreme heat in the U.S., similar to existing fire safety education.<\/p>\n “Sport often asks us to push ourselves harder, be faster and tougher,” Murfree said. “It’s OK to take breaks, stop, slow down, reschedule and advocate for our bodies and our wellness in the heat.”<\/p>\n This article is for informational purposes only and is not meant to offer medical advice.<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/XQ5DqDxyGFacZSu8vnPibR.jpg\")
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