This past weekend, many regions of the United States experienced extreme heat waves, with temperatures in Las Vegas and Palm Springs hitting above 100 degrees Fahrenheit. With threats of global warming, these waves of heat could become more common over the next several years. Many factors impact the heat our bodies experience, such as humidity, wind, and sun exposure. Our bodies core temperature is usually regulated to be around 98 degrees Fahrenheit, but temperatures can vary when placed under extreme weather conditions, during one’s menstrual cycle, or during an infection. But what exactly happens to our bodies physiologically when under this form of extreme heat?
How does our body regulate temperature?
During a heat wave, usually a glass of cold water, ice cream, or even sitting in the shade are ways that our bodies regulate temperature behaviorally. These are usually conscious decisions we make when temperatures are high. However, our body also regulates our temperature subconsciously through dilating blood vessels, sweating, and more. Under heat, our blood vessels dilate. A combination of both these behavioral and autonomic methods of regulation is how our body regulates its temperature.
What happens during heat illness?
There are many physiological aspects to heat illness. Muscle cramping, extreme sweating, and fatigue are all extremely common. Sweating results in a loss of sodium, which can often induce muscle cramps. Heat exhaustion can occur when the body reaches temperatures of 101.3 to 104 degrees Fahrenheit. At these high temperatures, the heart is often unable to function normally due to the body’s demands for blood flow throughout the whole body. The body must thermoregulate and work to provide blood flow to the muscles. These competing demands can often cause a lot of stress on the body.
Heat stroke occurs when the body temperature rises to above 104 degrees Fahrenheit. This is an extremely dangerous condition that can cause the nervous system to dysfunction and for organs to fail.
What about exercising in the heat?
It is commonly known that exercise is necessary to maintain positive health. Even under the heat, there are a couple of advantages to exercise. Some studies have shown that exercise under the heat can enhance performance during short, high-intensity workouts due to elevated muscle temperature. However, it is also important to note that heat stress on muscles can increase the body’s metabolic demands that are already under stress due to high temperatures.
Overall, it is important to stay cool during heat waves to protect against heat illness and heat stroke. Our bodies have the amazing ability to thermoregulate, but extreme conditions may cause physiological damage.
Sources:
Ball, Derek. “Contrasting effects of heat stress on neuromuscular performance.” Experimental physiology vol. 106,12 (2021): 2328-2334. doi:10.1113/EP088191
Périard, Julien D et al. “Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies.” Physiological reviews vol. 101,4 (2021): 1873-1979. doi:10.1152/physrev.00038.2020
Yoon, John. “100 Degrees at Midnight: California Coast Swelters in ‘concerning’ Heat.” The New York Times, The New York Times, 6 Sept. 2024, www.nytimes.com/2024/09/06/us/heat-wave-california-night-temperatures.html.
Image Source:
Adams, Ginger Otis, and Talal Ansari. “Heat Wave Brings High Temperatures to Dallas, St. Louis, Chicago and More - WSJ.” The Wall Street Journal, 14 June 2022, www.wsj.com/articles/heat-wave-could-bring-record-highs-to-dallas-st-louis-chicago-and-more-11655141353. Assessed and Endorsed by the MedReport Medical Review Board
