Seasonal influence on cognitive and psycho-physiological responses to a single 11-h day of work in outdoor mine industry workers

Abstract

This study investigated the seasonal effects that working outdoors had on various parameters in mining industry workers over the course of a work-shift. Workers ( n = 27) were assessed in summer (33.3 ± 4.2°C, 38 ± 18% RH; n = 13, age = 46 ± 14 y, BMI = 29.1 ± 5.7 kg/m 2 ) and winter (23.6 ± 5.1°C, 39 ± 20% RH; n = 14, age = 44 ± 12 y, BMI = 31.2 ± 4.1 kg/m 2 ). Core temperature and heart-rate were measured continuously (analyzed at five time points), while perceptual measures, cognitive and manual dexterity performance were assessed at various times over an 11-h shift at the start of a 14-day swing. Hydration was assessed (urine specific gravity) pre- and post-shift. Working memory was impaired in summer compared to winter (−10%; p = 0.039), however did not change throughout the shift. Processing efficiency was significantly reduced at 12 pm (−12%; p = 0.005) and 5 pm (−21%; p < 0.001) compared to 9 am, irrespective of season ( p > 0.05). Manual dexterity (dominant-hand) improved over the shift (+13%, p = 0.002), but was not different between seasons. Perceived fatigue had no main effect of season or shift. Core temperature, heart-rate, thermal sensation and rating of perceived exertion increased throughout the shift, with only core temperature and thermal sensation showing a seasonal effect (summer: +0.33°C, +18%, respectively; p < 0.002). Notably, 23% of workers in summer and 64% in winter started work significantly dehydrated, with 54% and 64% in summer and winter, respectively, finishing work with significant to serious dehydration. Impairment in working memory in summer combined with high levels of dehydration over the work-shift reinforces the need for workplace education on the importance of hydration and risk of occupation heat stress. Abbreviations: Core temperature: T c ; Fly-in fly-out: FIFO; Ratings of perceived exertion: RPE; Relative humidity: RH; Urinary specific gravity: USG; Wet bulb globe temperature: WBGT.

Comparing thermal strain in outdoor maintenance and indoor service workers in the mining industry during summer

“…This task requires counting the green dots on a sequence of cards containing yellow and green dots and then recalling the cards in order, with set size increasing from 2 to 7. The recorded variables included counting latency, first recall latency, subsequent recall latency, number of cards counted correctly, number of cards recalled correctly and counting span [ 26 ]. Individual counting and recall latency times (ms) were aggregated across all trials with the same number of target dots, or within the relevant serial position, respectively.…”

Impact of living and working in the heat on cognitive and psycho-physiological responses in outdoor fly-in fly-out tradesmen: a mining industry study

“…This task requires participants to count the green dots on a sequence of cards containing yellow and green dots and then recall the counts in order, with set size ranging from 2 to 7. Counting latency, first recall latency, subsequent recall latency, recall latency, number of cards counted correctly, number of counts recalled correctly and counting span were recorded ( Taggart et al, 2023 ). Individual counting and recall latency times (ms) were aggregated across all trials with the same number of target dots, or within the relevant serial position, respectively.…”

Living in Western Australia induces some physiological adaptations of seasonal acclimatisation in the surgical burns team

“…Perceptual adaptations include a lowered rating of perceived exertion and thermal sensation, and an improved rating of thermal comfort when exposed to heat [ 16 , 18 , 19 ]. While researchers have explored the influence that acclimation can have on occupational thermal strain [ 20 , 21 ], the potential for seasonal acclimatization has not been explored in depth in an occupational context, specifically one in which heat stress is a common occurrence. A lower resting T CORE and HR have been reported in summer compared to winter, in individuals living in in Korea [ 22 ] and Japan [ 23 ], respectively, where individuals experience differences in ambient temperatures between seasons.…”