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Eur J Appl Physiol (2012) 112:21712183 DOI 10.1007/s00421-011-2192-9
ORIGINAL ARTICLE
Body regional inuences of L-menthol applicationon the alleviation of heat strain while wearing reghters protective clothing
Joo-Young Lee Kouhei Nakao Ilham Bakri
Yutaka Tochihara
Received: 14 May 2011 / Accepted: 21 September 2011 / Published online: 2 October 2011 Springer-Verlag 2011
Abstract The purpose of this study was to investigate the inuences of menthol application according to the amount of surface area on physiological and psychological heat strains, along with body regional inuences. Male students underwent two stages of experiments: [Experiment 1] Cutaneous thermal threshold test at rest on eight body regions with/without a 0.8% menthol application at Ta 28C and 50% RH; [Experiment 2] Six exercise tests with/ without a 0.8% menthol spray at Ta 28C and 40% RH, while wearing reghters protective clothing (No menthol, PCNO; Face and neck menthol, PCFN; Upper body menthol, PCUP; Whole body menthol application, PCWB) or wearing normal clothing (No menthol, NCNO; Upper
body menthol, NCUP). Experiment 1 showed that menthol caused no signicant inuence on cutaneous warm thresholds, while menthol applications evoked earlier detection of cool sensations, especially on the chest (P = 0.043). Experiment 2 revealed that NCUP, PCUP and
PCWB caused lower mean skin temperature, especially with higher peripheral vasoconstrictions on the extremities at rest. During exercise, NCUP, PCUP and PCWB induced
greater and earlier increases in rectal temperatures (Tre) and
a delayed sweat response, but lessened psychological burdens (P \ 0.05). Both physiological and psychological
effects of PCFN were insignicant. For a composite analysis, individual Menthol Sensitivity Index at cooling in
Experiment 1 had signicant relationships with the threshold for Tre increase and changes in heart rate in NCUP of Experiment 2 (P \ 0.05). Our results indicate that menthols topical inuence is body region-dependent, as well as depending on the exposed body surface area.
Keywords Menthol Heat strain Fireghter
Protective clothing Cutaneous thermal threshold
Introduction
Fireghting is an occupation that requires strenuous physical feats. The individual reghter engages in various activities, such as ladder and stair climbing, victim rescue and equipment transportation, as well as ghting res. It has been reviewed that reghters in rescue operations consume oxygen in the range of 16 * 55 ml kg-1 min-1 (Cheung et al. 2010). Personal...