Impact of type 2 diabetes on cardiorespiratory function and exercise performance

The aim of this study was to examine the impact of well-controlled uncomplicated type 2 diabetes (T2D) on exercise performance. Ten obese sedentary men with T2D and nine control participants without diabetes matched for age, sex, and body mass index were recruited. Anthropometric characteristics, blood samples, resting cardiac, and pulmonary functions and maximal oxygen uptake (VO2max) and ventilatory threshold were measured on a first visit. On the four subsequent visits, participants (diabetics: n = 6; controls: n = 7) performed step transitions (6 min) of moderate-intensity exercise on an upright cycle ergometer from unloaded pedaling to 80% of ventilatory threshold. VO2 (τVO2) and HR (τHR) kinetics were characterized with a mono-exponential model. VO2max (27.0 ± 3.4 vs. 26.7 ± 5.0 mL kg-1 min-1; P = 0.85), τVO2 (43 ± 6 vs. 43 ± 10 sec; P = 0.73), and τHR (42 ± 17 vs. 43 ± 13 sec; P = 0.94) were similar between diabetics and controls respectively. The remaining variables were also similar between groups, with the exception of lower maximal systolic blood pressure in diabetics (P = 0.047). These results suggest that well-controlled T2D is not associated with a reduction in VO2max or slower τVO2 and τHR.