title: Oxygen uptake kinetics during exercise are slowed in patients with peripheral arterial disease.
abstract: Patients with peripheral arterial disease (PAD) have arterial occlusions that limit peripheral blood flow. This study evaluated the dynamic response in O(2) consumption (VO(2)) at the onset of constant-load exercise (VO(2) kinetics) in patients with PAD. Eight patients with bilateral PAD, seven patients with unilateral PAD, nine age-matched nonsmoking controls, and seven smoking controls performed graded treadmill exercise to assess peak VO(2). Subjects also performed constant-load exercise tests at 2.0 miles/h at 0 and 4% grade to determine VO(2) kinetics. Peak VO(2) was reduced 50% in patients with PAD compared with both control groups (P < 0.05). At 4% grade, phase 2 VO(2) kinetics were significantly slowed for the PAD groups compared with controls (60.1 +/- 15.7 and 58.7 +/- 8.3 s, unilateral and bilateral PAD groups, respectively; compared with 28. 4 +/- 19.3 and 27.9 +/- 8.1 s, nonsmoking and smoking controls, respectively; P < 0.05). No relationship was found between VO(2) kinetics and disease severity. These data demonstrate that VO(2) kinetics are markedly slowed in patients with PAD. The impairment in VO(2) kinetics is not related to smoking status or arterial disease severity and therefore may reflect altered control of skeletal muscle metabolism.
authors.affiliation: Section of Vascular Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Bauer
authors.forename: J G
authors.initials: JG
authors.lastname: Regensteiner
authors.forename: E P
authors.initials: EP
authors.lastname: Brass
authors.forename: W R
authors.initials: WR
authors.lastname: Hiatt
mesh_terms: D000368:Aged; D001161:Arteriosclerosis / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D007700:Kinetics; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D012907:Smoking