The Scientific Reason You’re So Brain Foggy Over The Summer

While the warm, lingering days of summer are doubtless a wonderful thing, the brain fog that can accompany surging temperatures is actually real — and it doesn’t feel so wonderful. According to new research published in PLOS Medicine, summer heat waves may slow down brain function — so if you’re wondering why your brain feels foggy when it’s super hot out, it turns out there’s a reason for it. Heat stress, as it's called, can muss up our thinking, MindBodyGreen reports, and make our normal cognitive functions less effective — so our normal day-to-day tasks become more challenging to tackle.

The researchers studied two groups of college students. One group had access to air conditioning in their dorms, while the other group didn’t. Researchers tested students’ cognitive function through tests administered via their cell phones twice a day for 12 days. The tests centered on simple math equations, and also questions designed to assess attention span and mental processing acuity. NPR notes that study author Joe Allen, co-director of the Center for Climate, Health, and the Global Environment at Harvard University, said that “There’s evidence that our brains are susceptible to temperature abnormalities.” So even as that summer heat wave might make us feel more lethargic, it can actually slow down our thinking, as well.

According to MindBodyGreen, access to AC had a major impact on how well students performed during the study. Researchers found that students with no access to AC had lower math scores, and slower overall brain processing times and critical thinking skills. Basically, a super hot heat wave combined with no AC meant that students test scores suffered by a lot. Allen told NPR, “We found that students who were in the non-air conditioned buildings actually had slower reaction times: 13 percent lower performance on basic arithmetic tests, and nearly a 10 percent reduction in the number of correct responses per minute.” Allen further explained that a slow, steady rise in temperatures can impact our cognitive functions more than we realize.

NPR also notes that these findings are the latest to add to a growing body of research examining how heat affects brain function. A 2006 study from the Lawrence Berkeley National Lab showed that office workers’ performance suffered when indoor temperatures rose above the mid-70s range, NPR further reports. And another study conducted at Harvard showed that taking standardized tests on hot days negatively impacted student’s performance and test outcomes as well. Researchers have since concluded that brain function and productivity rates are best at around 72 degrees Fahrenheit.

So while these findings are good news for those with access to indoor AC, if your abode is sans central air, there are things you can do to cool off indoors. According to Lifehacker, there are some key strategies for staying cool during a heat wave without AC. Guzzling plenty of fresh water, noshing on frozen treats and cooling foods, like salads, smoothies, and popsicles, and keeping the air circulating with fans are all helpful tips. And you can also invest in some heat blocking curtains for daytime, while making sure to open your windows to let the cooler air in at night. And a portable air conditioner can be relatively inexpensive to snag too.

Remember that if you start to experience the signs of heat stress or exhaustion, like brain fog, dizziness, dehydration, or a queasy stomach, it’s best to glug lots of water and seek out a cooler environment in order to cool down. And if you’ve got a big exam or work project coming up, seeking out cooler climes as much as possible in order to optimize your performance and brain function is a good idea, too.