Heat Waves Reduce Cognitive Performance

Extreme heat can have severe consequences for public health and extreme heat is the leading cause of death from meteorological phenomena within the USA. Temperatures appear to be rising worldwide, with impacts of extreme heat being well documented, most of which have focused on vulnerable populations and tend to be epidemiologic studies using outdoor temperature records. Gaining better understandings of the effects of indoor temperatures is important when you take into consideration American adults spend 90% of their time indoors.

44 students were enrolled to participate in this study who were in their late teens to early 20s residing in dorm rooms; 24 lived in adjacent buildings with central air, and the remaining 20 lived in low rise building without air conditioning. Each of the participant’s rooms were fitting with a device to measure temperature, humidity, carbon dioxide levels, and noise levels; physical activity and sleep patterns were tracked with wearable devices over a period of 12 days. Each day participants took 2 cognition tests on their smartphones right after waking up, the first required correct identification of the colour of displayed words used to evaluate cognitive speed and inhibitory control; and the second consisted of basic arithmetic questions to assess cognitive speed and working memory.

Findings showed during the heat wave students without air conditioning performed worse on the tests and experienced decreases across five measures of cognitive function which included reaction times and working memory; these students experienced 13.4% longer reaction times on colour word tests and 13.3% lower math test scores. Students in air conditioned rooms were faster in responses and were also more accurate.