title: Effects of slow deep breathing at high altitude on oxygen saturation, pulmonary and systemic hemodynamics.
abstract: Slow deep breathing improves blood oxygenation (Sp(O2)) and affects hemodynamics in hypoxic patients. We investigated the ventilatory and hemodynamic effects of slow deep breathing in normal subjects at high altitude. We collected data in healthy lowlanders staying either at 4559 m for 2-3 days (Study A; N = 39) or at 5400 m for 12-16 days (Study B; N = 28). Study variables, including Sp(O2) and systemic and pulmonary arterial pressure, were assessed before, during and after 15 minutes of breathing at 6 breaths/min. At the end of slow breathing, an increase in Sp(O2) (Study A: from 80.2±7.7% to 89.5±8.2%; Study B: from 81.0±4.2% to 88.6±4.5; both p<0.001) and significant reductions in systemic and pulmonary arterial pressure occurred. This was associated with increased tidal volume and no changes in minute ventilation or pulmonary CO diffusion. Slow deep breathing improves ventilation efficiency for oxygen as shown by blood oxygenation increase, and it reduces systemic and pulmonary blood pressure at high altitude but does not change pulmonary gas diffusion.
authors.affiliation: Department of Cardiology, San Luca Hospital, Istituto Auxologico Italiano, Milan, Italy.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Bilo
authors.forename: Miriam
authors.initials: M
authors.lastname: Revera
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bussotti
authors.forename: Daniele
authors.initials: D
authors.lastname: Bonacina
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Styczkiewicz
authors.forename: Gianluca
authors.initials: G
authors.lastname: Caldara
authors.forename: Alessia
authors.initials: A
authors.lastname: Giglio
authors.forename: Andrea
authors.initials: A
authors.lastname: Faini
authors.forename: Andrea
authors.initials: A
authors.lastname: Giuliano
authors.forename: Carolina
authors.initials: C
authors.lastname: Lombardi
authors.forename: Kalina
authors.initials: K
authors.lastname: Kawecka-Jaszcz
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mancia
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Agostoni
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Parati
mesh_terms: D000531:Altitude; D002245:Carbon Dioxide / Q000378:metabolism; D015444:Exercise; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007558:Italy; D008168:Lung / Q000502:physiology*; D008297:Male; D009390:Nepal; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D010313:Partial Pressure; D012123:Pulmonary Ventilation / Q000502:physiology; D012119:Respiration
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen