Algorithm for breathing efficiency

A method of determining a fitness level of a user comprising:

• wirelessly receiving at a controller, from a physiological sensor to be positioned on the user proximate the user's chest, throat, or mouth, configured to measure an airflow, an airflow value being based on a measurement of the airflow of the user using the physiological sensor;
• correlating the measured airflow value into a measurement of the user's respiratory rate and tidal volume;
• calculating a respiratory rate value by inputting the measured tidal volume into an exponential regression equation and relating the respiratory rate and the tidal volume to calculate the respiratory rate value;
• calculating a breathing efficiency (BE) ratio based on a comparison of the user's measured respiratory rate and the calculated respiratory rate value;
• correlating the calculated BE ratio to a predetermined threshold;
• and
• assigning a classification to the user based on the calculated BE ratio, the classification being indicative of the user's respiratory function performance.