title: Thermal face protection delays finger cooling and improves thermal comfort during cold air exposure.
abstract: When people dress for cold weather, the face often remains exposed. Facial cooling can decrease finger blood flow, reducing finger temperature (T (f)). This study examined whether thermal face protection limits finger cooling and thereby improves thermal comfort and manual dexterity during prolonged cold exposure. T (f) was measured in ten volunteers dressed in cold-weather clothing as they stood for 60 min facing the wind (-15°C, 3 m s(-1)), once while wearing a balaclava and goggles (BAL), and once with the balaclava pulled down and without goggles (CON). Subjects removed mitts, wearing only thin gloves to perform Purdue Pegboard (PP) tests at 15 and 50 min, and Minnesota Rate of Manipulation (MRM) tests at 30 and 55 min. Subjects rated their thermal sensation and comfort just before the dexterity tests. T (f) decreased (p < 0.05 for time × trial interaction) by 15 min of cold exposure during CON (33.6 ± 1.4-28.7 ± 2.0°C), but not during BAL (33.2 ± 1.4-30.6 ± 3.2°C); and after 30 min T (f) remained warmer during BAL (23.3 ± 5.9°C) than CON (19.2 ± 3.5); however, by 50 min, T (f) was no different between trials (14.1 ± 2.7°C). Performance on PP fell (p < 0.05) by 25% after 50 min in both trials; MRM performance was not altered by cold on either trial. Subjects felt colder (p < 0.05) and more uncomfortable (p < 0.05) during CON, compared to BAL. Thermal face protection was effective for maintaining warmer T (f) and thermal comfort during cold exposure; however, local cooling of the hands during manual dexterity tests reduced this physiological advantage, and performance was not improved.
authors.affiliation: Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA. kate.obrien@us.army.mil
authors.forename: Catherine
authors.initials: C
authors.lastname: O'Brien
authors.forename: John W
authors.initials: JW
authors.lastname: Castellani
authors.forename: Michael N
authors.initials: MN
authors.lastname: Sawka
mesh_terms: D000328:Adult; D000388:Air; D001831:Body Temperature / Q000502:physiology*; D003020:Clothing; D003080:Cold Temperature; D005145:Face / Q000502:physiology*; D005385:Fingers / Q000502:physiology*; D006801:Humans; D008297:Male; D012881:Skin Temperature / Q000502:physiology; D013697:Thermosensing / Q000502:physiology*; D055815:Young Adult