Data from: Internal and external cooling methods and their effect on body temperature, thermal perception and dexterity

Objective: The present study aimed to compare a range of cooling methods possibly utilised by occupational workers, focusing on their effect on body temperature, perception and manual dexterity.

Methods: Ten male participants completed eight trials involving 30 min of seated rest followed by 30 min of cooling or control of no cooling (CON) (34 °C, 58 % relative humidity). The cooling methods utilised were: ice cooling vest (CV0), phase change cooling vest melting at 14 °C (CV14), evaporative cooling vest (CVEV), arm immersion in 10 °C water (AI), portable water-perfused suit (WPS), heliox inhalation (HE) and ice slushy ingestion (SL). Immediately before and after cooling, participants were assessed for fine (Purdue pegboard task) and gross (grip and pinch strength) manual dexterity. Rectal and skin temperature, as well as thermal sensation and comfort, were monitored throughout.

Results: Compared with CON, SL was the only method to reduce rectal temperature (P=0.012). All externally applied cooling methods reduced skin temperature (P<0.05), though CV0 resulted in the lowest skin temperature versus other cooling methods. Participants felt cooler with CV0, CV14, WPS, AI and SL (P<0.05). AI significantly impaired Purdue pegboard performance (P=0.001), but did not affect grip or pinch strength (P>0.05).

Conclusion: The present study observed that ice ingestion or ice applied to the skin produced the greatest effect on rectal and skin temperature, respectively. AI should not be utilised if workers require subsequent fine manual dexterity. These results will help inform future studies investigating appropriate pre-cooling methods for the occupational worker.

研究目的：本研究旨在对比职业工作者可能采用的多种降温方法，重点考察其对体温、热感知及手动灵活性的影响。
方法：招募10名男性受试者完成8组试验，每组试验包含30分钟静息，随后进行30分钟降温处理或无降温对照（control, CON），试验环境为34℃、相对湿度58%。本次试验采用的降温方法包括：冰降温背心（ice cooling vest, CV0）、14℃相变降温背心（phase change cooling vest, CV14）、蒸发降温背心（evaporative cooling vest, CVEV）、手臂浸入10℃冷水（arm immersion in 10℃ water, AI）、便携式水冷服（water-perfused suit, WPS）、氦氧混合气吸入（heliox inhalation, HE）以及冰沙摄入（ice slushy ingestion, SL）。在降温处理前后，分别对受试者的精细动作（普渡钉板任务）与粗动作（握力与捏力）手动灵活性进行评估。全程监测受试者的直肠温度、皮肤温度，以及热感觉与热舒适程度。
结果：与对照组CON相比，仅SL组可显著降低受试者的直肠温度（P=0.012）。所有外用降温方法均可降低皮肤温度（P<0.05），其中CV0组的皮肤温度最低，优于其余降温方法。受试者使用CV0、CV14、WPS、AI及SL时，主观感知更为凉爽（P<0.05）。AI组显著损害了普渡钉板任务的表现（P=0.001），但对握力与捏力无显著影响（P>0.05）。
结论：本研究发现，冰沙摄入与皮肤外敷冰分别对直肠温度与皮肤温度的调控效果最为显著。若职业工作者后续需要开展精细手动操作，则不应采用AI（手臂浸入冷水）降温方式。本研究结果可为未来针对职业工作者适宜预降温方法的相关研究提供参考依据。