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

Abstract

To determine the exercise training–induced changes in peak oxygen uptake (V̇O _2peak ) 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. V̇O _2peak was assessed during incremental cycling while the time constant of the primary phase of oxygen uptake kinetics (τV̇O _2p ), blood pressure, and cardiac output (inert gas rebreathing) were measured during submaximal cycling before and after the intervention. V̇O _2peak increased and τV̇O ₂ p 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 V̇O _2peak and τ V̇O _2p in early and late middle‐aged adults with T2D. The improvements in V̇O ₂ kinetics appear to occur independently of systemic cardiovascular adaptations.