title: Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists.
abstract: This study investigated if well-trained cyclists improve V ˙ O 2 m a x and performance in cool conditions following heat acclimatization through natural outdoor training in hot conditions. Eighteen trained male cyclists were tested for physiological adaptations, V ˙ O 2 m a x , peak aerobic power output, exercise efficiency, and outdoor time trial (TT) performance (43.4 km in cool environment, ∼5-13 °C) before and after 2 weeks of training in a cool (CON, n = 9) or hot (∼35 °C, HA, n = 9) environment. After heat acclimatization, TT performance in the heat was improved by 16%; however, there was no change in the HA group in V ˙ O 2 m a x (4.79 ± 0.21 L/min vs 4.82 ± 0.35 L/min), peak aerobic power output (417 ± 16 W vs 422 ± 17 W), and outdoor TT performance in cool conditions (300 ± 14 W/69 ± 3 min vs 302 ± 9 W/69 ± 4 min). The present study shows that 2 weeks of heat acclimatization was associated with marked improvements in TT performance in the heat. However, for the well-trained endurance athletes, this did not transfer to an improved aerobic exercise capacity or outdoor TT performance in cool conditions.
authors.affiliation: Athlete Health and Performance Research Centre, Aspetar Orthopaedic Sports Medicine Hospital, Doha, Qatar; Department of Nutrition, Exercise and Sport Sciences, Section of Human Physiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Karlsen
authors.forename: S
authors.initials: S
authors.lastname: Racinais
authors.forename: M V
authors.initials: MV
authors.lastname: Jensen
authors.forename: S J
authors.initials: SJ
authors.lastname: Nørgaard
authors.forename: T
authors.initials: T
authors.lastname: Bonne
authors.forename: L
authors.initials: L
authors.lastname: Nybo
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D015308:Anaerobic Threshold; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D002980:Climate; D003080:Cold Temperature; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D013997:Time Factors
keywords: Maximal oxygen uptake; cycling; exercise efficiency; plasma volume; power output; time trial performance; well-trained athletes