Intermittent claudication. The effect of physical training on walking tolerance and venous lactate concentration

Twenty-one patients with intermittent claudication underwent a physical exercise program lasting 8 weeks. The patients were classified on the basis of maximal walking tolerance (MWT) and diagnosis at the initial examination. Seven of the patients had a MWT less than 1,000 m and no symptoms of chronic obstructive airways disease (COAD) or angina (group A), seven had a MWT less than 1,000 m plus angina and/or COAD (group B) and seven had an unlimited (greater than 1,250 m) MWT (group C). At the completion of the training program all three groups showed a significant improvement in walking distance to pain and stress test capacity. During the post-training walking tolerance test, the venous lactate concentrations in group A were lower after 2 min and 4 min of exercise, and at exhaustion (P less than 0.05). Group A patients showed a significant correlation between an increase in MWT after training and a decrease in maximum lactate concentration measured during walking. Although the patients in group B had a significant increase in MWT, blood lactate concentrations in this group were not always decreased by physical training. Group C lactate concentrations were lower after 8 min, 15 min, and 30 min of walking (P less than 0.05). It is concluded that a physical training program increases walking tolerance in different categories of claudicants, and possible mechanisms for the improvement are discussed.