A NEW RESPIRATORY VALVE SYSTEM FOR MEASURING OXYGEN-UPTAKE DURING SWIMMING

We describe a new respiratory valve system with minimal dead space, wh ich allows measurement of ventilation and oxygen uptake during swimmin g. The device offers considerable advantages in efficiency and accurac y over current equipment, and can be used in conjunction either with a miniaturized telemetry system for oxygen uptake measurement or with a conventional system. The valve has a low airflow resistance, a small dead space (15 ml), and an electrically operating, closed-circuit pump to remove excess water from the expiratory tube. The external form an d the buoyancy of the valve have been hydrostatically and hydrodynamic ally designed to reduce drag and to ensure a correct mass in the water . To obtain this result a very sophisticated material, carbon fibre, h as been utilized. Our studies showed that this respiratory system is i deal for obtaining valid and reliable values of oxygen uptake during s wimming, even at high speed and in endurance swimming tests.