Abstract

Introduction: Whilst there are many studies of the benefits of non-invasive respiratory support in cardiovascular and respiratory compromised individuals during the insufflation period, little is known on what effects, if any, remain following the insufflation. Aim of study: The present study was carried out to investigate the effects of nasal insufflation on various physiological variables and exercise performance in a group of male endurance athletes under respiratory stress. Materials and methods: Eight male competitive endurance athletes (30 ± 6 yr, VO2max: 65 ± 8 ml kg-1 min-1) were exposed for 30 minutes to: i) 25 L min-1 nasal insufflation with air at 37°C and fully saturated with water, ii) 25 L min-1 nasal insufflation with air at approximately 20°C and 50% relative humidity, and iii) no nasal insufflation and breathing air at approximately 20°C and 50% relative humidity. They then cycled at three five-minute preset work-rates followed by a 15 min self-paced time-trial where they completed as much work as possible. Results: When pre-treated with air at 37°C and fully saturated with water, there was a significant reduction of the respiratory exchange ratio throughout the pre-set work-rates (P < 0.03) and the amount of work completed in the time-trial was also significantly reduced (P < 0.03). Conclusion: The possible mechanisms for these long term changes and their potential significance are discussed. Verf.-Referat