Reliability of estimation of metabolic levels from respiratory frequency

¹ Industrial Health Research Unit, Section of Physiological and Industrial Hygiene, All-India Institute of Hygiene and Public Health, Calcutta, India

The reliability of estimating the physiological energy cost from the respiratory frequency has been tested from 114 exercise experiments on 11 volunteers. A correlation according to E (kcal/min) = –3.06 + 0.198R (no/min) was obtained between energy consumption and breathing rate. This regression was highly significant (P < 0.01) with a correlation constant of 0.93 and standard error of only 0.46 kcal/min. The convenience of the method in comparison with pulse rate and pulmonary ventilation methods which have similar correlation and accuracy, have been discussed. In states of low energy metabolism and also in the performance of severe muscular tasks, when oxygen debt may occur, the present relation may not strictly apply. Breath amplitude also affects energy levels, but it seems to bear no relation to the effect of respiratory frequency. Techniques for observing respiratory frequencies accurately and for deriving the best estimate of energy cost under field conditions are described. Determinations of energy consumption to the first approximation are readily achieved by this method.

Submitted on May 21, 1963