Warm nights prevent the body from recovering from heat stress, putting vulnerable populations at greater risk during prolonged heat waves.
Warm overnight temperatures during extended heat waves pose a hidden danger to vulnerable populations, preventing the body from fully recovering from the heat stress of the day.
During a typical heat wave, cool nights allow the body to refresh after extreme daytime heat. But when overnight temperatures remain elevated, that recovery process is disrupted.
Eric Ernest of Nebraska Medicine explained the toll warm nights take on the body.
"If we're still having ambient temps up in the 80s, and it's not really cooling off much, that continues to put a toll on those vulnerable populations," Ernest said.
During the recent heat wave, high temperatures reached the upper 90s while overnight lows only dropped to around 75 degrees. Those persistently warm overnight lows, day after day, add to cumulative heat stress on the body.
Air conditioning lowers the risk for many groups. It's our vulnerable neighbors, including the elderly, very young children, people who sleep outside, and those with certain medical conditions. However, people with conditions like diabetes or high blood pressure face elevated threats.
Ernest said warm nights can also affect the cardiovascular system.
"It blunts the response of the cardiovascular system where maybe the heart doesn't beat as hard, or blood vessels don't constrict or function in the way that they naturally would," Ernest said.
Health officials offer three key takeaways for staying safe during the heat wave: limit time outside, drink plenty of water, and find shade when you do have to be outdoors.
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