A sensitive electronic monitor (Mini-Motionlogger,
Ambulatory Monitoring Inc.) attached to the wrist was used
to record movements during two 24-hr days of ambulatory
blood pressure (BP) and heart rate (HR) recording 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 relationship between various measures of physical activity
and ambulatory BP and HR during waking and sleeping periods
and during various diary-defined behaviors. For waking
and sleeping periods, neither the mean nor the 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 either waking or sleeping conditions
with most participants showing a slightly positive association.
The activity measure discriminated between behaviors associated
with little effort (watching television) versus more energetic
behaviors (walking). Activity accounted for a relatively
small amount of the difference in BP or HR related to overall
state (wake, sleep), posture (stand, sit), and social condition
(being with family vs. being with friends). The utility
of electronic activity monitoring for studies of BP and
HR in natural settings is discussed.