Feeling a little mentally sluggish in the summer heat? Scientific research shows you’re not alone. Generally, studies showing negative effects of high temperatures focus on the elderly and other vulnerable people or involve artificial lab situations, but researchers at Harvard University recently assessed the effects of heat on young, healthy individuals in a real-world setting. Scientists studied 44 college students for 12 days before, during, and after a heat wave: half lived in air-conditioned dorms and half did not.
The results, published in PLOS Medicine, showed the students without air conditioning experienced a 4 to 13 percent reduction in their performance in attention, cognitive speed, and memory tests, and a nearly 10 percent reduction in the number of correct answers per minute. The scientists suggested that related factors such as poor ventilation, noise from fans, decreased hydration, and lack of sleep may have contributed to their results.
Although heat appears to make learning more difficult, most people likely don’t notice, Joseph Allen, one of the researchers, told NPR. “I think it's a little bit akin to the frog in the boiling water,” he said. “There’s a slow, steady—largely imperceptible—rise in temperature, and you don’t realize it’s having an impact on you.” —J.B.