Exercise-and post-exercise metabolism of the lower leg in patients with peripheral arterial insufficiency

Exercise- and post-exercise metabolism were studied in the lower legs of six subjects without known arterial insufficiency and in sixteen claudicants. Lower leg blood flow was measured with a thermodilution catheter in the popliteal vein. The catheter allowed blood sampling from the calf before, during and after an exhaustive, stepwise increasing load exercise on a bicycle ergometer. A higher oxygen extraction and higher lactate release during exercise in claudicants than in normal subjects persisted in the post-exercise period (P less than 0.05). Leg arteriopoplitealvenous differences of free fatty acids (FFA) showed an inverse intergroup relationship to that of glucose. Being higher in claudicants than in normal subjects during exercise (P less than 0.05). However, net uptake of FFA was not significantly different in the groups of legs although it appeared increased relative to glucose in claudicants both during and after the exercise. Thus no statistically significant substrate preference was detected although the results suggests a preference for FFA relative to glucose in legs with arterial insufficiency. The study furthermore demonstrated the lag of exercise metabolism into the post-exercise period in such legs and a close relationship between this metabolic delay and the severity of the disease.