Acute cold exposure and cognitive function: evidence for sustained impairment

Abstract

Several industries experience periods of cold exposure and rewarming throughout the workday but mental performance under these conditions is unknown. A better understanding of cognition during the rewarming phase after cold exposure may help reduce accidents and improve performance. Ten young men (wearing~0.1 clo) underwent 3 consecutive mornings trials where they were exposed to cold air (10°C) and then subsequently re-warmed (25°C air). A computerized test battery was administered during each stage of the protocol to determine working memory, choice reaction time, executive function, and maze navigation. Rectal and skin temperature, oxygen consumption, and thermal sensation were also measured throughout and showed a typical response. Relative to baseline performance, working memory, choice reaction time, and executive function declined during exposure to 10°C, and these impairments persisted 60 minutes into the recovery period (i.e. once physiological parameters had returned to baseline). Further work is needed to develop countermeasures to this predicament.

A review of human thermal comfort in the built environment

“…In a US study, subjects were exposed to cold conditions (10ºC) and then to 25ºC [368]. The authors concluded that cognitive function is reduced during the cold exposure and that such reduction persisted for one hour during the rewarmed period [368]. In China, another study involving two groups of subjects (one exposed to temperature variations and the other exposed to 26°C) concluded that a warm discomfort environment had a negative effect on performance.…”

“…Another study in a climate chamber in a non-steady thermal environment in Denmark (users could only change their clothes) found no difference in productivity amongst the analyzed thermal conditions (19.0-26.8ºC) [367]. In a US study, subjects were exposed to cold conditions (10ºC) and then to 25ºC [368]. The authors concluded that cognitive function is reduced during the cold exposure and that such reduction persisted for one hour during the rewarmed period [368].…”

Acute cold stress and mild hypothermia impact on short-term, working memory and attention

“…Pilcher et al (2002) performed meta-analysis and demonstrated that under cold conditions (~10 °C) reasoning, learning and memory tasks were impaired. Exposure to acute cold stress impairs the performance of short-term or working memory (Thomas et al, 1989;Duncko et al, 2009) and attention (Teichner, 1958;Muller et al, 2012). Baddeley et al (1975) reported a significant decrement in memory recall but not in recognition; however, other authors have reported a significant decrement in recognition but not in recall (Ellis et al, 1985).…”

“…Moreover, some investigators used a model in dogs and compared ice-water immersion (1 to 3 °C), coldwater immersion (10 to 11 °C), and tap-water immersion (15 to 16 °C) and found no significant differences among the 3 immersions (Magazanik et al, 1980). Most of investigations analyzing cold stress responses to cognitive performance were limited by exposure time (Mäkinen et al, 2006;Lieberman et al, 2009;Muller et al, 2012;Seo et al, 2013), but in a recent study Brazaitis et al (2014) induced cold stress by body immersion in cold water and examined the physiological responses in two groups of subjects: those who exhibited a fast decrease in rectal temperature (T re ) (fast cooling, FC) and those who exhibited a slow decrease in T re (slow cooling, SC). Accordingly, we assume that cold exposure, limited by time in earlier studies, might induce different responses on T re and subject's cognitive function could be affected differently.…”

“…The main activities associated with exposure to cold include boating, snowmobiling, other types of land and air transport, non-aquatic activities such as walking, playing, skating, hunting and fishing on ice, and other non-aquatic activities. Also, cold stress may occur for builders, divers, fire-fighters and other workers in everyday occupational activities, especially in winter.It is well documented that exposure of humans to cold induces physiological changes and may affect cognitive performance (Palinkas, 2001;Lieberman et al, 2009;Muller et al, 2012).Most of the effects related to cold induce an increment in error numbers and changes in response times in the performance of cognitive 2 Henrikas Paulauskas, Marius Brazaitis, Dalia Mickevičienė, Kazimieras Pukėnas, Nerijus Eimantas performance tests assessing attention and memory. Memory tests are used to assess the stages of short-term memory: memorization, storage and recall (Morey, Cowan, 2005), and attention tests allow investigating the main characteristics of attention: stability, concentration, distribution and transfer (Correani, Humphreys, 2011).…”