title: Hypohydration effect on finger skin temperature and blood flow during cold-water finger immersion.
abstract: This study was conducted to determine whether hypohydration (Hy) alters blood flow, skin temperature, or cold-induced vasodilation (CIVD) during peripheral cooling. Fourteen subjects sat in a thermoneutral environment (27 degrees C) during 15-min warm-water (42 degrees C) and 30-min cold-water (4 degrees C) finger immersion (FI) while euhydrated (Eu) and, again, during Hy. Hy (-4% body weight) was induced before FI by exercise-heat exposure (38 degrees C, 30% relative humidity) with no fluid replacement, whereas during Eu, fluid intake maintained body weight. Finger pad blood flow [as measured by laser-Doppler flux (LDF)] and nail bed (T(nb)), pad (T(pad)), and core (T(c)) temperatures were measured. LDF decreased similarly during Eu and Hy (32 +/- 10 and 33 +/- 13% of peak during warm-water immersion). Mean T(nb) and T(pad) were similar between Eu (7.1 +/- 1.0 and 11.5 +/- 1.6 degrees C) and Hy (7.4 +/- 1.3 and 12.6 +/- 2.1 degrees C). CIVD parameters (e.g., nadir, onset time, apex) were similar between trials, except T(pad) nadir was higher during Hy (10.4 +/- 3.8 degrees C) than during Eu (7.9 +/- 1.6 degrees C), which was attributed to higher T(c) in six subjects during Hy (37.5 +/- 0.2 degrees C), compared with during Eu (37.1 +/- 0.1 degrees C). The results of this study provide no evidence that Hy alters finger blood flow, skin temperature, or CIVD during peripheral cooling.
authors.affiliation: United States Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760-5007, USA. o'brien@na.amedd.army.mil
authors.forename: Catherine
authors.initials: C
authors.lastname: O'Brien
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Montain
mesh_terms: D000328:Adult; D001831:Body Temperature; D003080:Cold Temperature; D003681:Dehydration / Q000503:physiopathology*; D005260:Female; D005385:Fingers / Q000098:blood supply*; D006801:Humans; D007101:Immersion; D017078:Laser-Doppler Flowmetry; D008297:Male; D012039:Regional Blood Flow; D012881:Skin Temperature; D014664:Vasodilation