Cold Stress Impacts Cognitive Performance in Healthy Volunteers: Results from a Randomized, Controlled, Cross-over Study

Humans exposed to cold environments for leisure or occupational activities may experience cold stress. Cold-related physical and mental stress can negatively affect cognitive performance. A recent literature review has pointed out that a single acute exposure to cold under controlled laboratory conditions (e.g., cold air or cold water) induces cognitive impairment with attention, processing speed, memory, and executive function being the most affected cognitive domains. Males and females seem to respond differently to short-term cold exposure, although results are not consistent. The aim of the study was to investigate the effect of acute and brief (15 min) exposure to low ambient temperatures of -10 degrees C compared with 5 degrees C and 20 degrees C on selected cognitive performance (reaction time, processing speed, and risky decision-making). We hypothesized that cognitive performance decreases at low temperatures with a sex difference, before core temperature changes. This randomized, controlled, crossover study was conducted in an environmental chamber (terraXcube) under controlled, replicable, and safe conditions in twenty-four healthy volunteers, females and males, aged between 18 and 60 years. Measurements included Psychomotor Vigilance Test (PVT), Balloon Analogue Risk Task (BART), and Digit Symbol Substitution Test (DSST). Cognitive performance, stress, and cold were subjectively rated with a visual analogue scale (VAS). Physiological data (including core and skin temperatures) were continuously recorded with a physiological monitoring system. Data were analysed using repeated measures analysis of variance (ANOVA), Friedman test, Generalised Estimating Equations (GEE), and correlation analysis. We identified transient impairments in cognitive performance in individuals wearing appropriate clothing. Cold exposure (-10 degrees C) affected attention by slowing response times and increasing the lapses, and decision-making by reducing risky behaviour. Heart rate, cold sensation, and stress, as well as thermal sensation and comfort, but not core temperature were different in the three experimental temperature exposures. No differences were found between male and female subjects in their cognitive performance. Our data support the distraction theory in the decline of cognitive performance even during a short exposure to cold temperatures. Such impairment should be carefully considered in people performing different activities in cold environments, even for a short time.