Assessment of exercise capacity in women with type 2 diabetes

The primary aim of this study was to compare the maximal oxygen uptake as evaluated from a submaximal exercise test (EVO2peak) to direct measurements of VO2peak during a maximal exercise test as means of monitoring the aerobic endurance capacity in women with type 2 diabetes (T2D). Twenty-seven women with T2D participated in the study. The program consisted of combined group training 1 h twice a week during 12 weeks and walks 1 h per week. EVO2 max was estimated using a submaximal exercise test on a bicycle ergometer ad modum Astrand. VO2peak and maximal work rate were measured using an incremental maximal exercise test on an electrically braked bicycle ergometer at baseline and after 6 and 12 weeks. EVO2peak was higher than VO2peak at baseline and significantly higher at 12 weeks (EVO2peak1.92+/-0.54 l min(-1), VO2peak 1.41+/-0.36, P<0.005). Maximal work rate increased significantly after 12 weeks (12+/-15, P<0.005) compared to baseline. The main finding of this study was that EVO2peak assessed using a submaximal exercise test, systematically overestimated VO2peak. The combined group training increased maximal work rate but not VO2peak. This is likely to reflect peripheral adaptation to exercise and/or improved mechanical efficiency.