Comparison of activity level in daily life with heart rate: Application to elderly persons of different ambulatory abilities.

Objectives: Normal activity monitoring methods are mainly useful for relatively healthy and ablebodied people, but are not necessarily appropriate for elderly persons who may have difficulty in walking, or for the frail who may be bedridden. The purpose of this study was to examine 24-hour heart rate recording for the comparison of activity levels in daily life of elderly persons of different ambulatory abilities.

Methods: Forty-two elderly females (mean, 82.1 years old) volunteered to participate in this study. The subjects were divided into four groups on the basis of their ambulatory status, and their 24-hour heart rate recordings were compared with their results of activity assessments.

Results: The results of activity assessments showed a tendency to decrease as the ambulatory ability of the group decreased. The "total heart beats", calculated as the sum of all heart rates over 24 hours, were almost the same among the four groups, and therefore did not show a similar tendency. However, the "total excess-beats product (TEBP)" correlated with the results of activity assessments. TEBP was calculated as the sum of all differences in beats between each heart rate in 24 hours and the mean heart rate during sleeping at night. Therefore, TEBP may reflect a more active state than the bedridden state.

Conclusions: These results suggest that comparison of activity levels in daily life using 24-hour heart rate recording might be possible by the calculation of TEBP, and that this method might be useful for the comparison of the activity levels of elderly persons of diffent ambulatory abilities.