The Temperature in Your House Affects Your Mental Power and Memory

Key Takeaways

• Brain on Heat: High temperatures impair memory, focus, and reaction time—especially during and after heatwaves without AC.

• Chilling Effects: Cold exposure also lowers mental performance, likely due to reduced brain blood flow and body temperature.

• Performance Boosters: Tyrosine and caffeine may help counteract the negative cognitive effects of both heat and cold.

Temperature Ups and Downs

Research shows that being too hot or too cold messes with your brain in important ways that impair your intellectual capacity. For instance, studies have found that in the summer, people who don’t have or use air conditioning do worse on tests of mental function than folks who keep cool with AC. And when researchers at Harvard looked at how 44 people coped with a heat wave in Boston, they found that the twenty who lived in a dorm without air conditioning had significantly more trouble with cognitive tests than did the twenty-four who lived in cool, temperature-controlled buildings.¹ The researchers report that the people living in the heat did worse in five measures of cognitive function including their reaction times, their working memory, their ability to focus on what they were doing and their learning ability.

End of the Heat Wave Saw Biggest Difference in Mental Function

The Harvard scientists also point out that the biggest difference in mental performance between the non-AC people and the ones in air conditioning occurred after the heat wave started to end, because in the un-airconditioned setting, the indoor temperatures remained significantly higher than in the cooled facility. They say this happened because the buildings in Massachusetts where the test was done are designed to retain heat in order to cope with the region’s cold winters. They aren’t designed to cool off quickly in the summer. Another study, this one at the University of Pittsburgh, shows that if you do an exercise that’s intense enough to make you sweat heavily, your mental performance also suffers. But in this test, the intellectual drop didn’t occur until an hour or two after the exercise session.² It sounds like a heavy workout is not a good idea hours before a demanding mental task.

Cold Takes a Toll, Too

Cold temperatures can also be a brain problem. In a study at Kent State University, men who were exposed to colder temperatures at various times during the day – down to around 50 degrees – and then warmed up, had problems performing well on mental tasks both while they were chilled and after they had warmed up.³ The Kent State scientists believe that when you are feeling chilly, your brain might actually become colder than the rest of your body. Plus, it’s possible that the cooler temperatures slow the blood supply to your brain as the brain’s blood vessels constrict – and the slowdown can make it harder to concentrate. Of course, the most obvious way to avoid most of these hot and cold related brain problems is to keep your house and workplace at a comfortable temperature. And if you exercise during the day and get hot enough to sweat, don’t schedule important meetings or tasks afterwards.

More Tips for Offsetting the Temperature Effect

Two other ways to offset temperature issues, say researchers, are to take tyrosine supplements and caffeine. Supplements of tyrosine, an amino acid, have been shown to “help maintain cognitive function in extreme environmental conditions.”⁴ One study found that when you’re exposed to hot temperatures, tyrosine protects the brain by maintaining the function of the neurotransmitters dopamine and norepinephrine. And other tests have found a similar benefit in cold temperatures.⁵ The second tip for mental performance is caffeine. Coffee and tea can support your mental powers when the temperature drops – though I haven’t seen any evidence that it helps during hot weather. But if you’re feeling cold, a test conducted on Navy Seals – who have to maintain a high level of physical and mental performance in challenging conditions – shows that caffeine improves “cognitive function, including vigilance, learning, memory, and mood state.”⁶ The test on the Seals found that 200 mg of caffeine, the amount in one 12-ounce cup of coffee, was enough to do the trick.