Disappearance of isocapnic buffering period during increasing work rate exercise at high altitude

Piergiuseppe Agostoni, Mariaconsuelo Valentini, Damiano Magrì, Miriam Revera, Gianluca Caldara, Francesca Gregorini, Grzegorz Bilo, Katarzyna Styczkiewicz, Giulio Savia, Gianfranco Parati

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: At sea level, ventilation kinetics are characterized during a ramp exercise by three progressively steeper slopes, the first from the beginning of exercise to anaerobic threshold, the second from anaerobic threshold to respiratory compensation point, and the third from respiratory compensation point to peak exercise. In the second ventilation phase, body CO2 stores are used to buffer acidosis owing to lactate production; it has been suggested that this extra CO2 production drives the ventilation increase. At high altitude, ventilation increases owing to hypoxia. We hypothesize that ventilation increase reduces body CO2 stores affecting ventilation kinetics during exercise. DESIGN: In eight healthy participants, we studied the ventilation kinetics during an exercise performed at sea level and at high altitude (4559 m). METHODS: We used 30 W/2 min step incremental protocol both at sea level and high altitude. Tests were done on a cyclo-ergometer with breath-by-breath ventilation and inspiratory and expiratory gas measurements. We evaluated cardiopulmonary data at anaerobic threshold, respiratory compensation point, peak exercise and the VE/VCO2 slope. RESULTS: At high altitude: (a) peak VO2 decreased from 2595±705 to 1745±545 ml/min (P

Original languageEnglish
Pages (from-to)354-358
Number of pages5
JournalEuropean Journal of Cardiovascular Prevention and Rehabilitation
Volume15
Issue number3
DOIs
Publication statusPublished - Jun 2008

Keywords

  • Exercise
  • High altitude
  • Isocapnic buffering period
  • Ventilation kinetics

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Epidemiology

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