Just 15-Min Walk Outside On Hot Summer Days Could Impair Cognitive Function, Make You Less Productive

It is better to avoid lunchtime walks on hot summer days, as it can impair cognitive performance, say researchers.

Taking a brief walk during lunch or an afternoon break could help refresh you, both physically and psychologically. But if the temperature is hot outside, it could end up doing more harm than good.

A study published this month in Building and Environment revealed that just 15 minutes of walking outside on a hot day impairs cognitive performance. This effect was most pronounced in sleep-deprived men, said the researchers from the University of Tsukuba.

So, workers and students in urban cities should better avoid lunchtime walks in the summer months as it could negatively impact their productivity and learning, they noted.

Impact of heat on learning and productivity

Even though workers and students in large cities have the convenience of air-conditioning indoors over the summer months, brief exposure to heat during commuting or breaks is inevitable. Whether such short exposure to hot environments have negative impact on cognition, earning and productivity has not been known.

To assess the effects of outdoor heat stress on cognitive performance, the researchers observed 96 students who were made to stay in an air-conditioned indoor environment during the Japanese summer and then to walk or have a break in a hot outdoor urban environment.

The students completed a simple arithmetic test in an air-conditioned room before either staying indoors, walking outside, or resting outside for 15 minutes, and then completed a second arithmetic test when they returned indoors. Any changes in the test performance were measured. Results showed that walking in a hot outdoor environment impaired cognitive performance.

Greater impact on sleep deprived people

According to the researchers, it was the combination of walking and being outside in the summer heat that had impacted cognitive performance. Furthermore, this effect was found more evident in people, specifically men, who were sleep deprived, having slept less than 5 hours.

Based on the findings, senior author Professor Hiroyuki Kusaka advised Japanese office workers and students, especially men, to be aware of this situation as they work and study.

The team is hoping that their study will help in finding ways to improve productivity and learning in workers and students in Japan and elsewhere.