The independent influences of heat strain and dehydration upon cognition

Heuvel, Anne M. J. van den; Haberley, Benjamin J; Hoyle, David J. R.; Taylor, Nigel A.S.; Croft, Rodney J.

doi:10.1007/s00421-017-3592-2

Cited by 29 publications

(19 citation statements)

References 55 publications

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“…The stepwise linear regression showed that from changes in subjective and physiological measures only change in gastrointestinal temperature explained the change in reaction times. This is in line with Heuvel et al showing more liberal and quick responses when gastrointestinal temperature is elevated [18]. In addition, Van Maanen et al, 2019, showed that the shorter response times are explained by the effect of lowering the information decision threshold (for more information on decision thresholds see [10,21,22]).…”

Section: Change In Response Timesupporting

confidence: 75%

“…In terms of response times, results showed that response times are shortened in the warm condition compared to the neutral condition which is in line with [6,10,18,19]. In part, faster response times can be explained by increased synaptic activity and faster muscle cross-bridge cycling which are associated with increased tissue temperature (Arrhenius law or Q10 effect) [19,20]; nevertheless, a main effect of time showed that the duration of the experiment and time in the water further decreased the response times in both neutral and warm condition -hence also indicating an independent effect on response time.…”

Section: Change In Response Timesupporting

confidence: 72%

“…by arousal) or exacerbated (e.g. by dehydration or solar load) by contextual influences [18,20,24]. It may not be justified to interpret that an increased gastrointestinal temperature in practice yields a lower accuracy on a timed decision task per se.…”

Section: General Discussion Practical Translations and Limitationsmentioning

confidence: 99%

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Time perception and timed decision task performance during passive heat stress

et al. 2020

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This study investigates the hypotheses that during passive heat stress, the change in perception of time and change in accuracy of a timed decision task relate to changes in thermophysiological variables gastrointestinal temperature and heart rate (HR), as well as subjective measures of cognitive load and thermal perception. Young adult males (N = 29) participated in two 60-min head-out water immersion conditions (36.5°C-neutral and 38.0°C-warm). Cognitive task measurements included accuracy (judgment task), response time (judgment ask), and time estimation (interval timing task). Physiological measurements included gastrointestinal temperature and heart rate. Subjective measurements included cognitive task load (NASA-TLX), rate of perceived exertion, thermal sensation, and thermal comfort. Gastrointestinal temperature and HR were significantly higher in warm versus neutral condition (gastrointestinal temperature: 38.4 ± 0.2°C vs. 37.2 ± 0.2°C, p < 0.01; HR: 105 ± 8 BPM vs. 83 ± 9 BPM, p < 0.01). The change in accuracy was significantly associated with the change in gastrointestinal temperature, and attenuated by change in thermal sensation and change in HR (r2=0.40, p< 0.01). Change in response time was significantly associated with the change in gastrointestinal temperature (r2=0.26, p< 0.002), and change in time estimation was best explained by a change in thermal discomfort (r2=0.18, p< 0.01). Changes in cognitive performance during passive thermal stress are significantly associated with changes in thermophysiological variables and thermal perception. Although explained variance is low (<50%), decreased accuracy is attributed to increased gastrointestinal temperature, yet is attenuated by increased arousal (expressed as increased HR and warmth thermal sensation).

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Section: Change In Response Timesupporting

confidence: 75%

Section: Change In Response Timesupporting

confidence: 72%

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Time perception and timed decision task performance during passive heat stress

et al. 2020

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“…On the other hand, no effects on cognitive performance (executive function, choice reaction, vigilance etc.) have been reported across a series of studies [ 7 , 8 , 31 , 32 , 36 – 39 ], although the dehydration-levels were comparable to the above-mentioned studies and the participants’ mood and wellness were negatively affected when participants were dehydrated [ 7 , 10 , 31 ].…”

Section: Introductionmentioning

confidence: 70%

High prevalence of hypohydration in occupations with heat stress—Perspectives for performance in combined cognitive and motor tasks

et al. 2018

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PurposeTo evaluate the prevalence of dehydration in occupational settings and contextualize findings to effects on performance in cognitively dominated tasks, simple and complex motor tasks during moderate and high heat stress.MethodsThe study included an occupational part with hydration assessed in five industries across Europe with urine samples collected from 139 workers and analyzed for urine specific gravity. In addition, laboratory experiments included eight male participants completing mild-intensity exercise once with full fluid replacement to maintain euhydration, and once with restricted water intake until the dehydration level corresponded to 2% bodyweight deficit. Following familiarization, euhydration and dehydration sessions were completed on separate days in random order (cross-over design) with assessment of simple motor (target pinch), complex motor (visuo-motor tracking), cognitive (math addition) and combined motor-cognitive (math and pinch) performance at baseline, at 1°C (MOD) and 2°C (HYPER) delta increase in body core temperature.ResultsThe field studies revealed that 70% of all workers had urine specific gravity values ≥1.020 corresponding to the urine specific gravity (1.020±0.001) at the end of the laboratory dehydration session. At this hydration level, HYPER was associated with reductions in simple motor task performance by 4±1%, math task by 4±1%, math and pinch by 9±3% and visuo-motor tracking by 16±4% (all P<0.05 compared to baseline), whereas no significant changes were observed when the heat stress was MOD (P>0.05). In the euhydration session, HYPER reduced complex (tracking) motor performance by 10±3% and simple pinch by 3±1% (both P<0.05, compared to baseline), while performance in the two cognitively dominated tasks were unaffected when dehydration was prevented (P>0.05).ConclusionDehydration at levels commonly observed across a range of occupational settings with environmental heat stress aggravates the impact of hyperthermia on performance in tasks relying on combinations of cognitive function and motor response accuracy.

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“…High fever and hypovolemia often develop simultaneously in a thermal environment [24]. Passive elevation of the body temperature induces blood flow redistribution to the skin [25] that leads to blood decline in central and other organs.…”

Section: Plos Onementioning

confidence: 99%

Swine hemorrhagic shock model and pathophysiological changes in a desert dry-heat environment

Shen

Wei²,

Wang³

et al. 2021

PLoS ONE

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Background This study aimed to establish a traumatic hemorrhagic shock (THS) model in swine and examine pathophysiological characteristics in a dry-heat environment. Methods Forty domestic Landrace piglets were randomly assigned to four study groups: normal temperature non-shock (NS), normal temperature THS (NTHS), desert dry-heat non-shock (DS), and desert dry-hot THS (DTHS) groups. The groups were exposed to either normal temperature (25°C) or dry heat (40.5°C) for 3 h. To induce THS, anesthetized piglets in the NTHS and DTHS groups were subjected to liver trauma and hypovolemic shock until death, and piglets in the NS and DS groups were euthanized at 11 h and 4 h, respectively. Body temperature, blood gas, cytokine production, and organ function were assessed before and after environmental exposure at 0 h and at every 30 min after shock to death. Hemodynamics was measured post exposure and post-shock at 0 h and at every 30 min after shock to death. Results Survival, body temperature, oxygen delivery, oxygen consumption, and cardiac output were significantly different for traumatic hemorrhagic shock in the dry-heat groups compared to those in the normal temperature groups. Lactic acid and IL-6 had a marked increase at 0.5 h, followed by a progressive and rapid increase in the DTHS group. Conclusions Our findings suggest that the combined action of a dry-heat environment and THS leads to higher oxygen metabolism, poorer hemodynamic stability, and earlier and more severe inflammatory response with higher mortality.

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The independent influences of heat strain and dehydration upon cognition

Cited by 29 publications

References 55 publications

Time perception and timed decision task performance during passive heat stress

Time perception and timed decision task performance during passive heat stress

High prevalence of hypohydration in occupations with heat stress—Perspectives for performance in combined cognitive and motor tasks

Swine hemorrhagic shock model and pathophysiological changes in a desert dry-heat environment

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