Daily Energy Expenditure in Men and Women Determined by Heart-rate Monitoring

In order to estimate the daily energy expenditure of healthy (free-living) adults, a simpler and more accurate technique was developed by modifying the 24h heart rate ratio (24h-HRR) method of Hashimoto et al. (1987). Seventeen healthy adults, 8 men and 9 women, aged 20-69 years, were employed for the experiment, and their heart rate (HR) was monitored with a daily trend graph. To calculate the daily energy expenditure, the method originally defines the 24h-HRR as the mean of the 24h-HR divided by resting HR×100. In the present study, the following three standard values, instead of resting HR, were employed to divide into the mean 24h-HR: 1) T-RHR; the mean value of resting HR for 15-30 min at 2h after breakfast obtained from the daily trend graph, 2) SHR-I; the mean value of HR for 6h during sleep obtained from the trend graph divided by 0.9, 3) SHR-II; the mean value of HR for 6h during sleep multiplied by 1.2. The values of daily energy cost calculated by the 24h-HRR method using these three standards were compared with those obtained by the VO2/HR method. The regression of the daily energy expenditure by the 24h-HRR method using SHR-II on that by the VO2/HR method was y=0.9570x+152 (kcal/day) and showed the highest correlation coefficient (r=0.958), with an average error of 1.9±5.9%. These results suggest that the use of SHR-II for the 24h-HRR method gives good predictive values of daily energy expenditure more easily than the original method.