Relationship of peak exercise capacity with indexes of peripheral muscle vasodilation
Kosmas, E.N.; Hussain, S.A.; Montserrat, J.M.; Levy, R.D.
Medicine and Science in Sports and Exercise 28(10): 1254-1259
1996
ISSN/ISBN: 0195-9131 PMID: 8897382 Document Number: 457629
Since leg muscles receive the majority of cardiac output and consume a large proportion of total oxygen consumption ( ovrhdot VO-2) during cycle exercise, maximum leg blood flow may be an important determinant of peak ovrhdot VO-2 ( ovrhdot VO-2peak). We investigated the relationships between parameters of active hyperemia after thigh tourniquet occlusion (alone or with calf exercise) with whole body peak exercise capacity during maximum cycle exercise. Twenty-one healthy male subjects, aged 19-39 yr, performed maximum incremental cycle exercise. Calf blood flow, conductance (blood flow/mean blood pressure), vasodilatory capacity (peak/baseline conductance), and duration of vasodilation were then determined with venous occlusive plethysmography under two conditions: 1) after thigh tourniquet occlusion for 10 min; 2) after ischemic calf exercise (thigh tourniquet occlusion with calf exercise to exhaustion). Group mean ovrhdot VO-2peak was 120 +- 35% (standard deviation) predicted. There was a significant relationship between ovrhdot VO-2Peak/ lean body mass and peak calf conductance after maximum ischemic calf exercise (r = 0.556; P lt 0.01). However, ovrhdot VO-2peak/lean body mass was more closely correlated with the duration of vasodilation after thigh tourniquet occlusion with ischemic calf exercise (r = 0.861; P lt 0.001). These results suggest that the duration of calf vasodilation after maximal ischemic calf exercise appears to be a better index of cycle exercise capacity in healthy subjects.