Is the PrO2 a Threshold Device?

No, the PrO2 is not a threshold device and is not limited to Residual Volume (RV) training. It provides real-time feedback displayed on a phone or tablet, offering unlimited levels of conditioning based on individuals’ capability and capacity.

Threshold trainers were designed to fix workload using a spring valve that opens as the user breathes and applies pressure. When the pressure exceeds the spring's resistance, the spring is stretched to allow flow. This only occurs at one point…at the Maximum Inspiratory Pressure or MIP, when the valve opens, the spring begins to recoil, and resistance reduces.

Most importantly, resistance is NOT applied through the range, only at the point of opening (MIP). The original Threshold devices manufactured had only 42 cm H20 top resistance. This is typically less than 40% of the required workload to condition the skeletal muscles in adult males.