Vitalog evaluation of physical activity. On
entry, 21 subjects from the three groups were
monitored with the Vitalog. In these subjects data
were continuously recorded for an average of
11.2 _+ 2.4 hours. During the monitoring sessions
all patients had an average of 13.3 _+ 7.9 bouts of
activity per hour above their individual heart rate and
activity level thresholds (Table V). The duration of
these active periods was brief, lasting 10.9 _+ 4.9
seconds. The number of active minutes per hour
(derived from the number and duration o'feach active
period) was also brief, averaging 2.3 -+ 1.6 minutes.
When the total duration of activity was normalized to
the total duration of the monitored session, only
4.1% + 2.8% of the awake hours were spent in an
active mode.