Postprandial augmentation index is reduced in adults with prediabetes following continuous and interval exercise training.

People with prediabetes have elevated risk for cardiovascular disease, in part, owing to arterial stiffness mediated by low insulin sensitivity. However, the effect the intensity and/or amount (i.e. kilocalories per session) of short-term exercise training on fasting and postprandial arterial stiffness is unknown. We tested the hypothesis that increased intensity and dose (i.e. amount) of exercise would be correlated with reduced fasting and postprandial arterial stiffness in obese adults with prediabetes. After randomization, 31 adults (age 61.4 ± 8.3 years, body mass index 32.1 ± 5.4 kg m-2 ) with prediabetes performed supervised continuous (CONT; n = 17; 70% of peak heart rate) or interval (INT; n = 14; 3 min at 50% of peak heart rate and 3 min at 90% of peak heart rate) cycling training for 60 min day-1 over 2 weeks. The amount of exercise was calculated using regression equations derived from oxygen uptake ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> </mml:math> ) and heart rate. Arterial stiffness [augmentation index (AI) and cartoid-femoral pulse wave velocity], insulin and glucose were determined during a 180 min 75 g oral glucose tolerance test (OGTT) and analysed by the total area under the curve (tAUC) pre- versus post-training. The simple index of insulin sensitivity, (SIIS )OGTT, was calculated; aerobic fitness (peak <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> </mml:math> ) and body mass were also assessed. Short-term training had no effect on weight but did improve peak <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> </mml:math> (P = 0.003), glucose tAUC180min (P = 0.01) and insulin sensitivity (P = 0.002), independent of intensity. The CONT and INT exercise significantly reduced AI 2 h postprandial (P = 0.008) and tAUC180min (P = 0.03). Reductions in fasted AI were related to exercise dose (trend: r = -0.37, P = 0.055). Increased peak <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> </mml:math> was linked to reduced fasted (r = -0.47, P = 0.01) and tAUC180min AI (r = -0.39, P = 0.05). Decreased AI tAUC180min was correlated with increased insulin sensitivity (r = -0.50, P = 0.009). Short-term CONT and INT training reduced postprandial arterial stiffness comparably in adults with prediabetes.