Exercise training improves cardiorespiratory fitness and oxygen uptake kinetics to a similar extent in early and late middle-aged adults with type 2 diabetes.

To determine the exercise training-induced changes in peak oxygen uptake (V̇O2peak) and oxygen uptake kinetics in early and late middle-aged adults with uncomplicated type 2 diabetes (T2D). Fifty inactive adults with T2D (16 females) were stratified into late middle-aged (60-70 years) and early middle-aged (37-59 years) cohorts and assigned to exercise training or control groups: late middle-aged training (TR-LMA, n = 12), late middle-aged control (CON-LMA, n = 9), early middle-aged training (TR-EMA, n = 17), or early middle-aged control (CON-EMA, n = 12). Training groups completed a supervised 12-week aerobic and resistance programme. V̇O2peak was assessed during incremental cycling while the time constant of the primary phase of oxygen uptake kinetics (τV̇O2p), blood pressure, and cardiac output (inert gas rebreathing) were measured during submaximal cycling before and after the intervention. V̇O2peak increased and τV̇O2p decreased (p < 0.001) in both training groups: TR-LMA (25.6 ± 5.7 to 28.2 ± 5.3 mL·kg-1·min-1; 39.8 ± 6.5 to 35.0 ± 7.3 s) and TR-EMA (25.3 ± 5.3 to 28.1 ± 5.3 mL·kg-1·min-1; 43.3 ± 9.0 to 33.8 ± 8.2 s), with no between-group differences. No changes occurred in CON-LMA or CON-EMA, and cardiovascular responses remained unchanged following training. Combined aerobic and resistance training similarly improved V̇O2peak and τV̇O2p in early and late middle-aged adults with T2D. The improvements in V̇O2 kinetics appear to occur independently of systemic cardiovascular adaptations.