title: The effects of positive airway pressure on cardiovascular responses, perceived effort and time to exhaustion during high-intensity exercise in healthy subjects.
abstract: OBJECTIVE
  We investigated the effects of continuous positive airway pressure (CPAP) on the time to fatigue, rates of perceived exertion (RPE), and cardiovascular responses during sustained, high-intensity exercise (80% of VO2peak).
  
  
  METHODS
  Healthy male subjects (N.=11) underwent CPAP adaptation at rest to exclude those who felt incapable of breathing with the device and to determine the hemodynamic-induced changes. Subjects performed two exercise sessions, pedaling at 80% of VO2peak with or without CPAP until volitional fatigue. Heart rate was measured continuously, and blood pressure and RPE were recorded every minute.
  
  
  RESULTS
  The time to exhaustion was increased in the sessions with CPAP compared with sessions without CPAP (889±270 s vs. 689±256 sec, respectively, P=0.037). There were no differences in the cardiovascular variables at the end of the exercise sessions with or without CPAP. The RPE was lower during exercise with CPAP, but it reached maximal values similar to those observed at the end of exercise without CPAP.
  
  
  CONCLUSIONS
  During sustained, high-intensity exercise (80% of VO2peak), CPAP extended the time to fatigue in healthy subjects but did not change the heart rate, blood pressure or rate pressure product. Additionally, the central and peripheral RPEs remained lower for a longer period of time during exercise with CPAP.
authors.affiliation: Physiotherapy Departament Plínio Leite University Center, Niterói, Brazil. Physicaltherapy in Hospital University Clementino Fraga Filho, Rio de Janeiro, Brazil - fisioenf@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: De Sant'anna
authors.forename: A
authors.initials: A
authors.lastname: Mafra Moreno
authors.forename: P P
authors.initials: PP
authors.lastname: Da Silva Soares
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D045422:Continuous Positive Airway Pressure; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*