title: Motion sickness increases the risk of accidental hypothermia.
abstract: Motion sickness (MS) has been found to increase body-core cooling during immersion in 28 degrees C water, an effect ascribed to attenuation of the cold-induced peripheral vasoconstriction (Mekjavic et al. in J Physiol 535(2):619-623, 2001). The present study tested the hypothesis that a more profound cold stimulus would override the MS effect on peripheral vasoconstriction and hence on the core cooling rate. Eleven healthy subjects underwent two separate head-out immersions in 15 degrees C water. In the control trial (CN), subjects were immersed after baseline measurements. In the MS-trial, subjects were rendered motion sick prior to immersion, by using a rotating chair in combination with a regimen of standardized head movements. During immersion in the MS-trial, subjects were exposed to an optokinetic stimulus (rotating drum). At 5-min intervals subjects rated their temperature perception, thermal comfort and MS discomfort. During immersion mean skin temperature, rectal temperature, the difference in temperature between the non-immersed right forearm and 3rd finger of the right hand (DeltaTff), oxygen uptake and heart rate were recorded. In the MS-trial, rectal temperature decreased substantially faster (33%, P < 0.01). Also, the DeltaTff response, an index of peripheral vasomotor tone, as well as the oxygen uptake, indicative of the shivering response, were significantly attenuated (P < 0.01 and P < 0.001, respectively) by MS. Thus, MS may predispose individuals to hypothermia by enhancing heat loss and attenuating heat production. This might have significant implications for survival in maritime accidents.
authors.affiliation: Swedish Defence Research Agency, Berzelius v 13, Karolinska Institutet, Stockholm, Sweden. nobel_gerard@hotmail.com
authors.forename: Gerard
authors.initials: G
authors.lastname: Nobel
authors.forename: Ola
authors.initials: O
authors.lastname: Eiken
authors.forename: Arne
authors.initials: A
authors.lastname: Tribukait
authors.forename: Roger
authors.initials: R
authors.lastname: Kölegård
authors.forename: Igor B
authors.initials: IB
authors.lastname: Mekjavic
mesh_terms: D000328:Adult; D001833:Body Temperature Regulation; D006801:Humans; D007035:Hypothermia / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D009041:Motion Sickness / Q000150:complications* / Q000503:physiopathology*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012768:Shivering