Generally speaking, walks in nature are usually regarded as good for our wellbeing, as they calm us down and allow us to recharge our batteries.  Research from the University of Tsukuba finds a dark side, however, as walks in the summer heat can drain us considerably and lower our cognitive levels.

Indeed, the researchers show that just 15 minutes on a hot day can be enough to impair our performance, with this particularly so for those who haven’t gotten enough sleep.  The researchers had long pondered how impactful working in urban heat islands, such as those found in cities like Tokyo, suffer after they leave their air-conditioned homes or offices during the summer months.

Heat exposure

“Previous experiments have used specialized climate chambers to test these effects. However, outdoor thermal environment differs significantly from indoor thermal environments in terms of radiation and wind,” the researchers say. “Radiation and wind have significant effects on thermal perception. Therefore, in order to assess the effects of outdoor heat stress on cognitive performance, experiments should be conducted in real outdoor environments.”

The researchers aimed to simulate a real-world scenario during the sweltering Japanese summer, with participants leaving their air-conditioned indoor environment to go for a walk outside in an urban environment.

The volunteers were then asked to complete a simple maths test before either staying indoors, having a 15-minute rest, or going outside for a 15-minute walk.  They then returned inside and did a second maths test to try and spot whether any changes in their performance had occurred.

The results show that the walk in the heat outdoors did indeed appear to impair the performance of the volunteers.  The researchers explain, however, that it wasn’t simply the heat that impaired their performance, but the combination of the heat and exercise that appeared to dim our wits.

The researchers hope that their findings will help to make us more aware of the impact our surroundings can have on our performance levels, especially if we’re already suffering as a result of poor sleep.