Effect of fluid temperature on the relation and agreement between perceptual and physiological strain during simulated work in a hot environment

IF 2.9 2区生物学 Q2 BIOLOGY

Journal of thermal biology Pub Date : 2025-02-01 DOI:10.1016/j.jtherbio.2025.104077

Fergus K. O'Connor , Brodie J. Richards , Leonidas G. Ioannou , Glen P. Kenny

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引用次数: 0

Abstract

Background

Cold fluid ingestion is recommended during work to maintain hydration status and physiological function. While monitoring the physiological strain index (PSI) during work in the heat is recommended, it is logistically challenging. Subjective estimates, i.e., perceptual strain index (PeSI), are thought to reflect PSI. However, it remains unclear if cold fluid influences an individual's perception of heat strain.

Methods

Twenty young adults (10 females) performed four 15-min bouts of moderate-intensity (200 W/m²) cycling in the heat (40°C, 13% RH), each separated by 15-min rest. On separate days, participants consumed 2 boluses consisting of 5.2 g/kg of cold (0°C) or warm fluid (37.5°C) before the first and third work bout. Rectal temperature (Tc) and heart rate (HR) were recorded to calculate PSI (0–10 scale). Rating of perceived exertion (RPE) and thermal sensation (TS) were recorded to calculate PeSI (0–10 scale). Tc, HR, TS, and RPE were compared between experimental trials and across work bouts via two-way ANOVAs. Relation between PSI, PeSI and fluid temperature were evaluated via linear mixed models. Mean bias (95% limits of agreement [LoA]) between PSI and PeSI was assessed via Bland-Altman analysis.

Findings

Tc, HR, TS and RPE were not influenced by fluid temperature (P ≥ 0.09), nor was the relation between PeSI and PSI (P = 0.11). Mean bias [95% LoA] between PSI and PeSI was greater in cold (−2.1 [-5.7 – 1.5]) compared to the warm fluid condition (−1.8 [-4.8 – 1.2], P = 0.008).

Conclusion

While the relation between PeSI and PSI was not influenced by beverage temperature the agreement between measures was worsened following cold fluid ingestion.

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来源期刊

Journal of thermal biology 生物-动物学

CiteScore

5.30

自引率

7.40%

发文量

196

审稿时长

14.5 weeks

期刊介绍： The Journal of Thermal Biology publishes articles that advance our knowledge on the ways and mechanisms through which temperature affects man and animals. This includes studies of their responses to these effects and on the ecological consequences. Directly relevant to this theme are: • The mechanisms of thermal limitation, heat and cold injury, and the resistance of organisms to extremes of temperature • The mechanisms involved in acclimation, acclimatization and evolutionary adaptation to temperature • Mechanisms underlying the patterns of hibernation, torpor, dormancy, aestivation and diapause • Effects of temperature on reproduction and development, growth, ageing and life-span • Studies on modelling heat transfer between organisms and their environment • The contributions of temperature to effects of climate change on animal species and man • Studies of conservation biology and physiology related to temperature • Behavioural and physiological regulation of body temperature including its pathophysiology and fever • Medical applications of hypo- and hyperthermia Article types: • Original articles • Review articles