title: Effects of a single bout of interval hypoxia on cardiorespiratory control in patients with type 1 diabetes.
abstract: Hypoxemia is common in diabetes, and reflex responses to hypoxia are blunted. These abnormalities could lead to cardiovascular/renal complications. Interval hypoxia (IH) (5-6 short periods of hypoxia each day over 1-3 weeks) was successfully used to improve the adaptation to hypoxia in patients with chronic obstructive pulmonary disease. We tested whether IH over 1 day could initiate a long-lasting response potentially leading to better adaptation to hypoxia. In 15 patients with type 1 diabetes, we measured hypoxic and hypercapnic ventilatory responses (HCVRs), ventilatory recruitment threshold (VRT-CO2), baroreflex sensitivity (BRS), blood pressure, and blood lactate before and after 0, 3, and 6 h of a 1-h single bout of IH. All measurements were repeated on a placebo day (single-blind protocol, randomized sequence). After IH (immediately and after 3 h), hypoxic and HCVR increased, whereas the VRT-CO2 dropped. No such changes were observed on the placebo day. Systolic and diastolic blood pressure increased, whereas blood lactate decreased after IH. Despite exposure to hypoxia, BRS remained unchanged. Repeated exposures to hypoxia over 1 day induced an initial adaptation to hypoxia, with improvement in respiratory reflexes. Prolonging the exposure to IH (>2 weeks) in type 1 diabetic patients will be a matter for further studies.
authors.affiliation: Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria.
authors.forename: Tobias
authors.initials: T
authors.lastname: Duennwald
authors.forename: Luciano
authors.initials: L
authors.lastname: Bernardi
authors.forename: Daniel
authors.initials: D
authors.lastname: Gordin
authors.forename: Anna
authors.initials: A
authors.lastname: Sandelin
authors.forename: Anna
authors.initials: A
authors.lastname: Syreeni
authors.forename: Christopher
authors.initials: C
authors.lastname: Fogarty
authors.forename: Janne P
authors.initials: JP
authors.lastname: Kytö
authors.forename: Hannes
authors.initials: H
authors.lastname: Gatterer
authors.forename: Markku
authors.initials: M
authors.lastname: Lehto
authors.forename: Sohvi
authors.initials: S
authors.lastname: Hörkkö
authors.forename: Carol
authors.initials: C
authors.lastname: Forsblom
authors.forename: Martin
authors.initials: M
authors.lastname: Burtscher
authors.forename: Per-Henrik
authors.initials: PH
authors.lastname: Groop
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D012119:Respiration; D016037:Single-Blind Method