Physiological and psychological adaptation to respiratory protective devices.

This study was conducted to investigate the adaptation process to respiratory protective devices (RPD). Twenty healthy subjects were tested at 80% of their Vo2 max for 6 consecutive days with a fitted RPD with an airway resistance of 2.80 +/- 0.07 cm H2O s/1. It was concluded that working with RPD at a work capacity close to maximum for several minutes per day induces a rapid adaptation process. This is demonstrated by an improvement in physiological parameters rather than in subjective sensations.