The Impact of Different Environmental Conditions on Cognitive Function: A Focused Review

Abstract

Cognitive function defines performance in objective tasks that require conscious mental effort. Extreme environments, namely heat, hypoxia, and cold can all alter human cognitive function due to a variety of psychological and/or biological processes. The aims of this Focused Review were to discuss; (1) the current state of knowledge on the effects of heat, hypoxic and cold stress on cognitive function, (2) the potential mechanisms underpinning these alterations, and (3) plausible interventions that may maintain cognitive function upon exposure to each of these environmental stressors. The available evidence suggests that the effects of heat, hypoxia, and cold stress on cognitive function are both task and severity dependent. Complex tasks are particularly vulnerable to extreme heat stress, whereas both simple and complex task performance appear to be vulnerable at even at moderate altitudes. Cold stress also appears to negatively impact both simple and complex task performance, however, the research in this area is sparse in comparison to heat and hypoxia. In summary, this focused review provides updated knowledge regarding the effects of extreme environmental stressors on cognitive function and their biological underpinnings. Tyrosine supplementation may help individuals maintain cognitive function in very hot, hypoxic, and/or cold conditions. However, more research is needed to clarify these and other postulated interventions.

Physiological responses and parasympathetic reactivation in rescue interventions: The effect of the breathing apparatus

“…Although the present study did not measure temperature, other studies have shown that wearing PPC increases core temperature, increases sweating, and leads to dehydration . A recent review reported that heat stress could decrease performance during “complex” cognitive tasks, such as executive functions . Consequently, the increase in core temperature with the PPC might also have had a negative impact on the participants’ cognitive functions.…”

Cognitive performance during passive heat exposure in Japanese males and tropical Asian males from Southeast Asian living in Japan

“…Therefore, it is not surprising to observe no performance degradation in short-term memory during heat exposure in both groups, although Johnson et al [9] and Wright et al [10] suggested that small changes in body temperature may have influence on human performance. However, a recent review by Taylor et al [34] suggests that core temperature alone may not be a reliable predictor of cognitive performance decline in hot environment. The task difficulty level could be the factor affecting cognitive function [1–3, 29].…”

“…Second, increase of core temperature alone might not be a reliable predictor of performance deterioration [34]. Japanese subjects reported more negative feelings during heat exposure condition than tropical subjects; they felt the condition was hotter and more thermally discomfort than tropical subjects.…”

Neurosensory and Cognitive Modifications in Europe's Toughest RandoRaid Competition: the Transpyrénéa Extreme Study

“…Fourth, altitude (Yan, 2014), hypoxia, heat and cold stress, known to be both task- and severity-dependent, are probably linked to the cognitive and sensory status of an athlete (Ruffini et al, 2015; Taylor et al, 2016) and are experienced by RandoRaid and ultra-trail athletes competing in a race like the Transpyrénéa.…”

“…To date, various evidence for significant effects on physical (Vitiello et al, 2013) and cognitive functions (Tomporowski, 2002; Cona et al, 2015; Hurdiel et al, 2015; Tonacci et al, 2016) of ultra-trailers has already been observed, mainly caused by a mix of high altitude exposure (Yan, 2014), environmental conditions (Lefferts et al, 2016; Taylor et al, 2016)—including cold, heat and hypoxia—muscular fatigue, dehydration (Cian et al, 2000), and sleep deprivation (Davis et al, 2014; Fullagar et al, 2015). …”