The thermoregulatory consequences of heat stroke: Are cytokines involved?

Leon, Lisa R.

doi:10.1016/j.jtherbio.2005.11.023

Cited by 39 publications

(52 citation statements)

References 76 publications

(197 reference statements)

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“…Among the five of seven Cape turtle doves that exhibited hyperthermic T b at T a =56°C, rates of T b increase remained fairly low, which we interpret as indicative of facultative, regulated hyperthermia rather than thermoregulatory breakdown and lethal heat stroke (Leon, 2006). Laughing and Namaqua doves showed similar patterns of hyperthermic T b combined with modest rates of T b increase at T a =58°C (mean T b =43.6°C) and 60°C (mean T b =43.8°C), respectively.…”

Section: Body Temperatures and Thermal Endpointsmentioning

confidence: 70%

Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern Hemisphere columbids

McKechnie

Whitfield

Smit

et al. 2016

Journal of Experimental Biology

113

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Birds show phylogenetic variation in the relative importance of respiratory versus cutaneous evaporation, but the consequences for heat tolerance and evaporative cooling capacity remain unclear. We measured evaporative water loss (EWL), resting metabolic rate (RMR) and body temperature (T b ) in four arid-zone columbids from southern Africa [Namaqua dove (Oena capensis, ∼37 g), laughing dove (Spilopelia senegalensis, ∼89 g) and Cape turtle dove (Streptopelia capicola, ∼148 g)] and Australia [crested pigeon (Ocyphaps lophotes), ∼186 g] at air temperatures (T a ) of up to 62°C. There was no clear relationship between body mass and maximum T a tolerated during acute heat exposure. Maximum T b at very high T a was 43.1±1.0, 43.7±0.8, 44.7±0.3 and 44.3±0.8°C in Namaqua doves, laughing doves, Cape turtle doves and crested pigeons, respectively. In all four species, RMR increased significantly at T a above thermoneutrality, but the increases were relatively modest with RMR at T a =56°C being 32, 60, 99 and 11% higher, respectively, than at T a =35°C. At the highest T a values reached, evaporative heat loss was equivalent to 466, 227, 230 and 275% of metabolic heat production. The maximum ratio of evaporative heat loss to metabolic production observed in Namaqua doves, 4.66, exceeds by a substantial margin previous values reported for birds. Our results support the notion that cutaneous evaporation provides a highly efficient mechanism of heat dissipation and an enhanced ability to tolerate extremely high T a .

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Section: Body Temperatures and Thermal Endpointsmentioning

confidence: 70%

Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern Hemisphere columbids

McKechnie

Whitfield

Smit

et al. 2016

Journal of Experimental Biology

113

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“…As examples, the Bedford Thermal Scale employs descriptors that range from "Much Too Cool" to "Comfortable" to "Much Too Warm" while the OMNI Thermal Sensation Scale employs descriptors "Comfortable" to "Very Hot." Additionally, visual analog scales may also assess thermal perception 39 that may increase sensitivity to changes in non-uniform conditions on the body surface. In essence, the visual analog scale is the developmental precursor or semantic differential for many perceptual indices such as the OMNI perceived exertion and muscle pain scales.…”

Section: Perceptual Heat Strain Indicesmentioning

confidence: 99%

Development of a perceptual hyperthermia index to evaluate heat strain during treadmill exercise

et al. 2011

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Fire suppression and rescue is a physiologically demanding occupation due to extreme external heat as well as the additional physical and thermal burden of the protective garments. The hot environment challenges body temperature homeostasis inducing heat stress. Accurate field assessment of hyperthermia is complex and unreliable. Purpose: The present investigation developed a perceptually based hyperthermia metric to measure physiologic exertional heat strain during treadmill exercise. Methods:Sixty-five (28.88 ± 6.75 yrs) female (n=11) and male (n=54) firefighters and non-firefighting volunteers participated in four related thermal stress investigations performing treadmill exercise while wearing thermal protective clothing in a heated room. Physiological and perceptual responses (i.e. body core temperature, perceived exertion, and thermal sensation) were assessed at baseline, 20-mins exercise, and at termination. Results: Perceived exertion increased from baseline (0.24 ± 0.42) to termination (7.43 ± 1.86). Thermal sensation increased from baseline (1.78 ± 0.77) to termination (4.50 ± 0.68). Perceived exertion and thermal sensation were measured concurrently with body core temperature to develop a twodimensional graphical representation of three "colored" exertional heat strain zones. Each exertional heat strain zone was representative of a range of mean body core temperature responses such that green incorporated 36.0 to 37.4°C, yellow incorporated 37.5 to 37.9°C, and red incorporated 38.0 to greater than 40.5°C. Conclusions: A perceptual hyperthermia index (PHI) was developed using ratings of iii perceived exertion and thermal sensation. The PHI can provide a quick and easy momentary assessment of the level of risk for exertional heat strain for firefighters engaged in fire suppression and rescue. This metric may be beneficial in high risk environments that threaten the lives of firefighters.

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“…42 IL-6 is elevated at this phase and the extent of elevation correlates with survival. 40 This hypothermic phase was not observed in correlation studies in patients with heatstroke; it is possible that treatment modalities masked the hypothermic phase.…”

Section: Cytokinesmentioning

confidence: 97%

“…If markedly elevated, heat causes protein denaturation and loss of activity, loss of membrane integrity and ultimate cell death. 45 The temperature associated with heatstroke ranges between 41 and 428C, 40 but temperatures as high as 478C have been reported. 36 Critical thermal maximum, the minimum core-body temperature that is lethal to an organism, is variable, making it difficult to predict thermal injury.…”

Section: Pathogenesismentioning

confidence: 99%

Clinical biochemistry of hyperthermia

Hashim

2010

Ann Clin Biochem

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Heatstroke is the most severe form of heat-related disorders that include mild heat intolerance, heat exhaustion and heat stress. The incidence of heat-related disorders is increasing due to several factors that include climate change, co-morbidities and drug usage. Patients with heatstroke present with a core body temperature above 408C, multiorgan dysfunction and central nervous system disorder. The pathogenesis of heatstroke is not fully understood; however, heat-shock proteins, inflammatory cytokines and their modulators have been implicated. The clinical biochemistry laboratory plays an important role in the management of patients with heatstroke. Biochemical findings in patients with heatstroke include elevated urea, creatinine, cardiac and skeletal muscle enzymes, myoglobin and troponin. There is also biochemical evidence of metabolic acidosis, respiratory alkalosis, hepatic injury with elevated enzyme levels as well as abnormal hematological and coagulation indices. This review article aims at increasing awareness of the biochemical changes seen in patients with heatstroke and their possible role in prognosis and in elucidating the pathogenesis of heatstroke.

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The thermoregulatory consequences of heat stroke: Are cytokines involved?

Cited by 39 publications

References 76 publications

Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern Hemisphere columbids

Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern Hemisphere columbids

Development of a perceptual hyperthermia index to evaluate heat strain during treadmill exercise

Clinical biochemistry of hyperthermia

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