Now that summer’s here, many of us are excited to get out and enjoy the warm sun and outdoors again—especially after a few months spent cooped up inside. There are plenty of benefits of direct sunlight: Vitamin D serves many important functions, and has been shown to reduce your risk of dying from coronavirus. And sunlight can also naturally boost your mood if you’ve been suffering from anxiety and depression. But we all know the expression “too much of a good thing.” And while the risks of overexposure to the sun are well documented, a new study shows there’s another danger that may surprise you: Too much sun can actually warm your brain and impair your cognitive performance.
The study, published in Scientific Reports in May, looked at the effects of direct sunlight on human brain temperature and function. Researchers found that prolonged exposure warmed the brain enough to diminish cognitive functions, including motor skills. That could make too much sun a serious safety hazard not just for your skin—but also for the rest of you.
The authors of the study noted that those who work outside in the hot sun might experience decreased productivity, in addition to the potential dangers of operating heavy machinery and completing other tasks with lowered cognitive function and motor skills. “The ability to maintain concentration and avoid attenuation of motor-cognitive performance is certainly of relevance for work and traffic safety as well as for minimizing the risks of making mistakes during other daily tasks,” study co-author Andreas Flouris, associate professor from FAME Laboratory in Greece, said in a statement.
While the study’s authors mostly discussed the impact of these findings on those who work outdoors, anyone who plans to spend time in extreme heat this summer should keep in mind the effect it could have on their brain. It’s worth noting that the decline in cognitive and motor performance happened with exposure to a temperature of 38.5 degrees Celsius—around 101 degrees Fahrenheit—which is significantly hotter than the average summer day. But with heat waves and rising temperatures worldwide, this study could be more relevant than ever.
“Health and performance impairments provoked by thermal stress are societal challenges intensifying with global warming and that is a prolonged problem we must try to mitigate,” Flouris said.
In the meantime, pay attention to the temperature outside, and avoid too much exposure to the sun on those extra hot days—sound medical advice for a number of reasons. If you do have to be outside for long periods of time in excessive heat, make sure you’re protecting your head. Your brain will thank you.