title: Effects of Two Short-Term, Intermittent Hypoxic Training Protocols on the Finger Temperature Response to Local Cold Stress.
abstract: The study examined the effects of two short-term, intermittent hypoxic training protocols, namely exercising in hypoxia and living in normoxia (LL-TH; n=8), and exercising in normoxia preceded by a series of brief intermittent hypoxic exposures at rest (IHE+NOR; n=8), on the finger temperature response during a sea-level local cold test. In addition, a normoxic group was assigned as a control group (NOR; n=8). All groups trained on a cycle-ergometer 1 h/day, 5 days/week for 4 weeks at 50% of peak power output. Pre, post, and 11 days after the last training session, subjects immersed their right hand for 30 min in 8°C water. In the NOR group, the average finger temperature was higher in the post (+2.1°C) and 11-day after (+2.6°C) tests than in the pre-test (p≤0.001). Conversely, the fingers were significantly colder immediately after both hypoxic protocols (LL-TH: -1.1°C, IHE+NOR: -1.8°C; p=0.01). The temperature responses returned to the pre-training level 11 days after the hypoxic interventions. Ergo, present findings suggest that short-term intermittent hypoxic training impairs sea-level local cold tolerance; yet, the hypoxic-induced adverse responses seem to be reversible within a period of 11 days.
authors.affiliation: 1 Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology , Stockholm, Sweden .
authors.forename: Michail E
authors.initials: ME
authors.lastname: Keramidas
authors.affiliation: 2 Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute , Ljubljana, Slovenia .
authors.forename: Stylianos N
authors.initials: SN
authors.lastname: Kounalakis
authors.affiliation: 1 Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology , Stockholm, Sweden .
authors.forename: Ola
authors.initials: O
authors.lastname: Eiken
authors.affiliation: 2 Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute , Ljubljana, Slovenia .
authors.forename: Igor B
authors.initials: IB
authors.lastname: Mekjavic
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000328:Adult; D000531:Altitude; D003080:Cold Temperature; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005385:Fingers / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D012881:Skin Temperature / Q000502:physiology*; D055815:Young Adult
keywords: acclimation; cold injury; cold tolerance; endurance training; finger circulation; high altitude