Decreased humidity improves cognitive performance at extreme high indoor temperature

Area of Science:

• Environmental Psychology
• Human Physiology
• Cognitive Science

Background:

• Extreme indoor temperatures pose a risk to cognitive function.
• The impact of humidity on cognitive performance at high temperatures is not fully understood.
• Subtropical acclimatization may influence thermal and cognitive responses.

Purpose of the Study:

• To investigate the effects of extreme high indoor temperature on cognitive performance.
• To determine the impact of decreased relative humidity on cognitive function under high heat.
• To correlate physiological and subjective responses with cognitive changes.

Main Methods:

• Forty-eight healthy subjects were exposed to three climate conditions: 26°C/70% RH, 39°C/70% RH, and 39°C/50% RH.
• Cognitive tests assessing perception, spatial orientation, concentration, memory, and thinking were administered over 140 minutes.
• Physiological parameters (heart rate, temperature, blood pressure, body weight) and subjective responses were monitored.

Main Results:

• Cognitive test accuracy significantly decreased when temperature increased from 26°C to 39°C at 70% RH.
• Decreasing relative humidity from 70% to 50% at 39°C significantly improved cognitive test accuracy.
• Physiological and subjective responses varied significantly with temperature and humidity changes, correlating with cognitive performance.

Conclusions:

• Elevated indoor temperatures significantly impair cognitive abilities.
• Reducing indoor humidity at extreme high temperatures can mitigate cognitive deficits.
• Environmental control, specifically humidity reduction, is crucial for maintaining cognitive function in hot conditions.