Classification(s): Exercise Testing
Introduction: Daily physical activity is associated with absolute claudication distance (ACD) in patients limited by intermittent claudication. However, it is unclear whether patients with worse exercise performance have lower activity levels because of spending less time in activity, engaging in less intense activity, or a combination of both.
Purpose: To determine the association between daily ambulatory activity patterns and exercise performance in patients with intermittent claudication.
Design: A cross-sectional study.
Methods: One hundred thirty-three patients limited by intermittent claudication participated. Patients were assessed on their ambulatory activity patterns for 1 week with a small, lightweight step activity monitor attached to their ankle using elastic Velcro straps above the lateral malleolus of the right leg. The step activity monitor recorded the number of strides taken on a minute-to-minute basis, and the time spent ambulating. Patients also were characterized on ankle/brachial index (ABI), ischemic window (IW) after a treadmill test, as well as initial claudication distance (ICD), and absolute claudication distance (ACD) during treadmill exercise.
Results: Patient characteristics (mean +/- SD) were as follows: ABI = 0.71 +/- 0.23, IW = 0.54 +/- 0.72 area over curve/meter walked, ICD = 236 +/- 198 meters, and ACD = 424 +/- 285 meters. The patients took 3366 +/- 1694 strides/day and were active for 272 +/- 103 minutes/day. The cadence for the 30 highest, consecutive minutes of each day (15.1 +/- 7.2 strides/minute) was correlated with ICD (r = 0.309, P < .001) and ACD (r = 0.492, P < .001), and the cadence for the 60 highest, consecutive minutes of each day (11.1 +/- 5.4 strides/minute) was correlated with ICD (r = 0.283, P < .01) and ACD (r = 0.477, P < .001). Similarly, the cadences for the highest 1, 5, and 20 consecutive minutes, and the cadence for the 30 highest, non-consecutive minutes all were correlated with ICD and ACD (P < .05). None of the ambulatory cadences were correlated with ABI (P > .05) or with ischemic window (P > .05).
Conclusions: Ambulatory cadences characteristic of short bursts of activity, as well as sustained and non-sustained endurance activities, are associated with intermittent claudication but not with peripheral circulation.