Effects of short-term endurance exercise training on vascular function in young males

We investigated effects of 6 days of endurance exercise training [cycling at 65% of peak oxygen consumption (VO_2peak) for 2 h a day on six consecutive days] on vascular function in young males. Measures of VO_2peak, arterial stiffness, calf vascular conductance and heart rate variability were obtained pre- and post-training. Indices of arterial stiffness were obtained by applanation tonometry to determine aortic augmentation index normalized to a heart rate of 75 bpm (AI _x @75 bpm), and central and peripheral pulse wave velocity (CPWV, PPWV). Resting and maximal calf vascular conductances were calculated from concurrent measures of blood pressure and calf blood flow using venous occlusion strain-gauge plethysmography. Time and frequency domain measures of heart rate variability were obtained from recording R–R intervals during supine and standing conditions. Both CPWV (5.9 ± 0.8 vs. 5.4 ± 0.8 m/s) and PPWV (9.7 ± 0.8 vs. 8.9 ± 1.3 m/s) were reduced following the training program. No significant changes were observed in AI _x @75 bpm, vascular conductance, heart rate variability or VO_2peak. These data indicate that changes in arterial stiffness independent of changes in heart rate variability or vascular conductance can be achieved in healthy young males following only 6 days of intense endurance exercise.