The summer is just coming to an end, and with it a period of heat wave. The elderly and babies in particular suffer from high temperatures and can be exhausted more quickly. Previous studies have measured the impact of heat mainly in such vulnerable groups, in laboratories where the heat could be controlled. But does extreme heat also affect cognitive ability in young people? 

Air conditioning on/off
In this new study, the researchers followed 44 young adults who lived in student rooms. Out of this group, 24 students lived in relatively new apartments (built around 1990) which came with AC. The remaining 20 students lived in buildings over 60 years old and did not have air conditioning included. The researchers installed a device in all the rooms to measure temperature, CO2 levels, humidity and sound. To measure the impact on cognition in a natural setting, the researchers waited until a heat wave approached Boston. The effects were measured over a 12-day period: five days with comparably normal summer temperatures for this area and five days during a heat wave. Finally, the measurements took place 2 more days once the weather cooled down. 

Naming colors
Meanwhile, study participants were asked to perform several tests on their cell phones on 12 consecutive days: the Stroop test and simple math tests. In the Stroop test, participants are shown words such as red or green, while the word may or may not have the corresponding color. The task is to name the color depicted as quickly as possible. In general, we are much slower to name the color of the word when it does not correspond to the content of the word.

The results showed that students in buildings without air conditioning performed worse on both tests than students who had air conditioning. Students with air conditioning were not only faster, but also more accurate in their answers. What was particularly surprising was that the greatest negative impact was seen during the two days when it cooled down outside. On these days, temperatures outside returned to normal, but living room temperatures were still on the high side.

So if you fail that test during a heat wave or do worse at your job in a room without air conditioning: refer to this study and demand a good air conditioner!

This study was  published in the journal PLoS Medicine

Author: Stefan Jongen (edited and translated by Sophie Ruppert)
Originally published on Brainmatters: June 18th, 2018