Journal of Science and Medicine in Sport (2008) 11, 542—548 ORIGINAL PAPER Thermoregulatory responses of junior lifesavers wearing protective clothing Wade H. Sinclair * , Melissa J. Crowe, Warwick L. Spinks, Anthony S. Leicht Institute of Sport and Exercise Science, James Cook University, Queensland, Australia Received 23 November 2006; received in revised form 16 May 2007; accepted 16 May 2007 KEYWORDS Child; Exercise; Heat; Protective clothing; Body temperature regulation Summary This study investigated the influence of protective clothing worn to prevent marine stinger envenomation on the thermoregulatory responses of pre- pubescent surf lifesavers exercising in situ under hot and humid conditions (27 ◦ C, 78% relative humidity). Participants performed beach and water activities typically associated with junior surf lifesaving competition in a randomised cross-over design on two separate occasions 7 days apart: one wearing a full-length Lycra stinger suit (S) and one wearing normal swimwear (SW). Skin (T SK ) and core (T C ) body temperatures, skin blood flow (SKBF), heart rate (HR), body mass, thermal com- fort and perceived effort were assessed pre-, mid- (following beach activities) and post-exercise (following water activities). Sweat rates were compared between S and SW. T C was greater following beach activities for S (37.78 ◦ C ± 0.06) com- pared to SW (37.60 ◦ C ± 0.07; p < 0.05) and male participants experienced greater T C (37.97 ◦ C ± 0.09) than their female counterparts (37.71 ◦ C ± 0.07 ◦ C). T SK follow- ing both the beach and water activities were lower than pre-exercise (p < 0.05). SKBF was significantly increased for calf across time (p < 0.01). Male participants experienced a higher HR for S compared to female participants (p < 0.01) while the opposite applied to SW (p < 0.01). There were no gender or between-condition dif- ferences for sweat rate or perceived effort. There was evidence of heat storage while stinger suits were worn during beach activities in the absence of any differ- ences in exercise intensity or sweat rate. The results of the present study suggest that the stinger suits should be limited to water-based activities. © 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Introduction Marine stinger species are endemic along the north Australian coastline between the warmer months of ∗ Corresponding author. E-mail address: Wade.Sinclair@jcu.edu.au (W.H. Sinclair). October and May and are known to initiate severe systemic, noxious and immunological pathologies or inflict death within minutes. 1 The north Queens- land marine stinger season parallels surf lifesaving activities in the region. As a result, the bathing public are required to swim within stinger-resistant netted enclosures and it is mandatory for junior 1440-2440/$ — see front matter © 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2007.05.010