Measurement Accuracy of Heart Rate and Respiratory Rate during Graded Exercise and Sustained Exercise in the Heat Using the Zephyr BioHarness™

The Zephyr BioHarness (TM) was tested to determine the accuracy of heart rate (HR) and respiratory rate (RR) measurements during 2 exercise protocols in conjunction with either a laboratory metabolic cart (Vmax) or a previously validated portable metabolic system (K4b(2)). In one protocol, HR and RR were measured using the BioHarness and Vmax during a graded exercise up to (V)over dotO(2max) (n = 12). In another protocol, HR and RR were measured using the BH and K4b(2) during sustained exercise (30% and 50% (V)over dotO(2max) for 20 min each) in a hot environment (30 degrees C, 50% relative humidity) (n = 6). During the graded exercise, HR but not RR, obtained from the BioHarness was higher compared to the Vmax at baseline and 30% (V)over dotO(2max) (p < 0.05), but showed no significant difference at other stages with high correlation coefficients for both HR (r = 0.87-0.96) and RR (r = 0.90-0.99 above 30% (V)over dotO(2max)). During the exercise in the heat, there were no significant differences between the BioHarness and K4b(2) system. Correlation coefficients between the methods were low for HR but moderately to highly correlated (0.49-0.99) for RR. In conclusion, the BioHarness is comparable to Vmax and K4b(2) over a wide range of (V)over dotO(2) during graded exercise and sustained exercise in the heat.