Letter by Poelkens et al Regarding Article, “Aerobic Interval Training Versus Continuous Moderate Exercise as a Treatment for the Metabolic Syndrome: A Pilot Study” To the Editor:

We read with great interest the article by Tjønna et al1 that addressed the efficacy of different modes of exercise training to reverse features of the metabolic syndrome. The metabolic syn-drome, considered an ailment of the 20th century, consists of a clustering of risk factors, with insulin resistance still viewed as the common pathophysiological pathway.2 We were intrigued by the fact that in patients with the metabolic syndrome, aerobic interval training substantially improved insulin sensitivity (homeostatic model assessment score increasing from 62.28.0 % to 77.24.9%), whereas continuous moderate exercise seemed to decrease insulin sensitivity (64.45.7 % versus 50.24.9 % before and after training, respectively). It should be noted that the homeostatic model assess-ment score as a derivate index for insulin sensitivity has clear limitations.3 The gold standard for measuring insulin sensitivity is the euglycemic hyperinsulinemic clamp, with the frequently sample