WRIST ACTIGRAPH MEASURES OF PHYSICAL-ACTIVITY LEVEL AND AMBULATORY BLOOD-PRESSURE IN HEALTHY ELDERLY PERSONS

A sensitive electronic monitor (Mini-Motionlogger, Ambulatory Monitori ng Inc.) attached to the wrist was used to record movements during two 24-hr days of ambulatory blood pressure (BP) and heart rate (HR) reco rding in 65 women and 54 men between the ages of 55 and 79 years, all of whom were in good health. The objective was to examine the relation ship between various measures of physical activity and ambulatory BP a nd HR during waking and sleeping periods and during various diary-defi ned behaviors. For waking and sleeping periods, neither the mean nor t he variability of the activity measure was associated with the mean or variability of the ambulatory BP and HR measures in between-subjects correlational analyses. Within-subject analyses showed little evidence of significant covariation between activity and BP or HR during eithe r waking or sleeping conditions with most participants showing a sligh tly positive association. The activity measure discriminated between b ehaviors associated with little effort (watching television) versus mo re energetic behaviors (walking). Activity accounted for a relatively small amount of the difference in BP or HR related to overall state (w ake, sleep), posture (stand, sit), and social condition (being with fa mily vs. being with friends). The utility of electronic activity monit oring for studies of BP and HR in natural settings is discussed.