Relationship between free-living daily physical activity and peripheral circulation in patients with intermittent claudication

The purpose of this study was to determine the relationship between free-li ving daily physical activity and peripheral circulation under resting, reac tive hyperemia, and maximal exercise conditions in peripheral arterial occl usive disease (PAOD) patients with intermittent claudication. Sixty-one PAO D patients (age=70 +/-6 years, ankle/brachial index [ABI] =0.57 +/-0.24) we re recruited from the Vascular Clinic at the Baltimore Veterans Affairs Med ical Center and from radio and newspaper advertisements. Free-living daily physical activity was measured as the energy expenditure of physical activi ty (EEPA), determined from doubly labeled water and indirect calorimetry. P atients also were characterized on ankle/brachial index, calf blood flow, c alf transcutaneous oxygen tension (TcPO2), and calf transcutaneous heating power (TcHP). ABI and calf blood flow served as markers of the macrocircula tion of the lower extremity, while TcPO2 and TcHP served as markers of the microcirculation. The claudication patients were sedentary, reflected by a mean EEPA value of 486 +/-274 kcal/day. EEPA was related to calf TcHP at re st (282 +/-24 mW; r=-0.413, p=0.002), after postocclusion reactive hyperemi a (275 +/-22 mW; r=-0.381, p=0.004), and after maximal exercise (276 +/-20 mW; r=-0.461, p<0.001). ABI, calf blood flow, and calf TcPO2 were not relat ed to EEPA under any condition. In conclusion, higher levels of free-living daily physical activity were associated with better microcirculation of th e calf musculature in older PAOD patients with intermittent claudication.