The effect of exercise on the dynamic responses of oxygen uptake and leg vascular conductance in people with type 2 diabetes mellitus

Abstract

People with type 2 diabetes mellitus (T2DM) suffer from exercise impairment which is characterised by a reduced peak exercise capacity (VO2 peak)- In order to better understand the aetiology of the exercise impairment in diabetics three experiments were performed. in the first experiment, VO2 kinetic responses of 9 uncomplicated T2DM females, 11 non-diabetic lean (Lean) and 9 non-diabetic overweight/obese (Ow/Ob) subjects were recorded during constant load cycle exercise at three exercise intensities (three 7 min bouts at low, moderate and high intensities) relative to each individuals ventilatory threshold (VT) and vO2peak- In addition, cardiac output (CO) responses (inert gas rebreathe technique) were recorded simultaneously (at 30 s and 240 s) during the constant load cycle exercise bouts. v02peak responscs were significantly lower in the diabetic group. In addition, biphasic resolution of the dynamic response of VO2 revealed significantly slowed kinetic responses characterised by a greater phase 2 time constant (t2) at low and moderate intensities in the T2DM group (low: 31.8±13.4 s, moderate: 39.1±9.0 s; P<0.05) compared to the Lean (low: 20.2±9.7 s, moderate: 24.8±12.1 s) and Ow/Ob (low: 15.4±7.3 s, moderate: 24.8±8.8 s) groups. CO responses were not different among the three groups.