title: Hand temperature responses to local cooling after a 10-day confinement to normobaric hypoxia with and without exercise.
abstract: The study examined the effects of a 10-day normobaric hypoxic confinement (FiO2: 0.14), with [hypoxic exercise training (HT); n = 8)] or without [hypoxic ambulatory (HA; n = 6)] exercise, on the hand temperature responses during and after local cold stress. Before and after the confinement, subjects immersed their right hand for 30 min in 8 °C water [cold water immersion (CWI)], followed by a 15-min spontaneous rewarming (RW), while breathing either room air (AIR), or a hypoxic gas mixture (HYPO). The hand temperature responses were monitored with thermocouples and infrared thermography. The confinement did not influence the hand temperature responses of the HA group during the AIR and HYPO CWI and the HYPO RW phases; but it impaired the AIR RW response (-1.3 °C; P = 0.05). After the confinement, the hand temperature responses were unaltered in the HT group throughout the AIR trial. However, the average hand temperature was increased during the HYPO CWI (+0.5 °C; P ≤ 0.05) and RW (+2.4 °C; P ≤ 0.001) phases. Accordingly, present findings suggest that prolonged exposure to normobaric hypoxia per se does not alter the hand temperature responses to local cooling; yet, it impairs the normoxic RW response. Conversely, the combined stimuli of continuous hypoxia and exercise enhance the finger cold-induced vasodilatation and hand RW responses, specifically, under hypoxic conditions.
authors.affiliation: Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: M E
authors.initials: ME
authors.lastname: Keramidas
authors.affiliation: Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Kölegård
authors.affiliation: Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.
authors.forename: I B
authors.initials: IB
authors.lastname: Mekjavic
authors.affiliation: Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: O
authors.initials: O
authors.lastname: Eiken
mesh_terms: D000328:Adult; D003080:Cold Temperature; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D017079:Exercise Tolerance; D006225:Hand / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D007101:Immersion; D012881:Skin Temperature; D013997:Time Factors; D014867:Water; D055815:Young Adult
chemical_list: D014867:Water
keywords: : CIVD; cold injury; cold tolerance; cross-adaptation; high altitude; rewarming