Comparison of HR-VO2 regression in mental and physical exertion.

Correlation between HR and VO2 during video watching was studied in comparison with that during bicycle ergometer working. Five healthy males volunteered as subjects. Subjects watched video program for 60 minutes and worked on a bicycle ergometer with incremental work loads of 25 W/2 minutes for 13 minutes. VO2 was significantly correlated with HR in both conditions, but the correlation coefficients and slopes of regression lines were lower in video watching than in bicycle ergometer working. Estimated energy expenditure during video watching from HR, based on the HR-VO2 regression of bicycle ergometer working, was 111% of the measured value. It was suggested that estimation of daily energy expenditure using HR -VO2 regression of dynamic work tend to be overestimated when daily life includes much mental work.