By Markham Heid
July 23, 2014
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What's the opposite of a brain freeze? There should be a word for that, because hot weather messes with your mind's ability to process complex information, make smart decisions, and keep your cool during confrontations. The summer heat even toys with your emotions.

Studies have found the most comfortable temperature for most people is right around 72 degrees. Here, experts explain how higher temps transform you into a hot mess.

High 70s

Compared to people working in a 67-degree room, those asked to complete a proofreading test in a 77-degree space took longer to complete the task and missed about 50 percent more of the typos. This was after just a quarter of an hour spent hanging out in the warm-ish workspace, according to the study from two American universities. A separate study from the same team found that, in warmer temps, people were also less willing and less able to make complex decisions-like picking out the cheapest cell phone plan among two options.

The study authors blame "depleted resources" for the warm group's performance decline. Your body uses up more energy keeping you cool than heating you up. (Sweating requires more energy than shivering, they explain.) Like trying to exercise when you're wiped out, your brain struggles to function properly when your over-warm body is hogging all the energy in an effort to stay cool, the authors suggest.

(Interesting note: The researchers point out that the human body is better able to endure cold than heat: People have been known to survive even if their internal temp drops 20 degrees. But Just a 10-degree rise in the other direction-or elevating your body temp from 98.6 to 108.6-would toast your brain, they say.)


As the temperature keeps rising, your memory for new information suffers, according to a study in the journal Ergonomics. Also, the longer you spend outside on a hot summer day, the more your mood worsens, finds a study from the University of Michigan. Science points to a few different explanations for these heat-related shortcomings (apart from the energy issues mentioned above): Dehydration has been tied to depleted brain function and mood, and you're more likely to be dehydrated in hot weather when you're body is sweating out a lot of moisture, studies show. High temps also disrupt your sleep, and so drowsiness could explain your irritable, poor-performing noodle, another study speculates.

90 Degrees and Hotter

While the above studies indicate your brain will continue to crap out the hotter it gets, a lot of past research has also linked higher temps to violent or aggressive behavior. John Simister, Ph.D., and colleagues in the U.K. found a connection between hot weather and higher rates of violent crime, worker strikes, and people quitting their jobs. Why? Scorching summer temperatures may lead people to overreact angrily when faced with everyday problems or confrontations, the research suggests.

While it's not proven, Simister says stress hormones like adrenaline may play a role. If you're attacked by an animal or put in some other life-threatening situation, your body pumps out adrenaline, which improves your reaction time, focuses your attention, and helps you prepare for fight or flight, he explains. And because exposure to ultra-high temps could also be life threatening, your body may release adrenaline to help you dodge heat-related dangers, he adds. Adrenaline also causes your heart rate to quicken, which helps speed blood to your skin in an effort to promote sweat and help you stay cool, he says.

"If you feel angry about something in hot weather, it may be better to cool down before you make an important decision," he advises. He also recommends sipping on cold, cold water as a good way to keep your brain (and temper) cool in the summertime.