Endothelial function and microvesicle concentration changes after acute bouts of continuous eccentric exercise have not been assessed previously nor compared to concentric exercise at similar aerobic power outputs. This method of training may be useful amongst some clinical populations, but acute responses are not well described. As such, twelve healthy males completed two experimental sessions of either 45 minutes of eccentric or concentric cycling at a matched aerobic power output below the ventilatory threshold. Brachial artery vascular function was assessed throughout 5 minutes of forearm ischemia and 3 minutes thereafter, before and at 5 and 40 minutes of recovery following each exercise session (flow mediated dilation: FMD). Venous blood samples were acquired prior to each vascular function assessment. FMD significantly decreased after eccentric cycling by 40 minutes of recovery (p<0.05), but was unaltered after concentric exercise. No differences in peak hyperaemic blood flow velocity occurred neither between modalities nor at any time point (p>0.05). Platelet derived microvesicles increased by ~20% after both exercise modalities (p<0.05) whilst endothelial derived microvesicles were unchanged (p>0.05). Moderate relationships with cardiac output, a surrogate for shear stress, and norepinephrine were apparent (p<0.05) but there were no relationships with inflammatory or acute phase proteins. In summary, eccentric endurance exercise induced macrovascular endothelial dysfunction, however endothelial activation determined by endothelial microvesicles did not occur suggesting that this modality may induce oxidative stress but no significant endothelial damage. In addition, the increase in platelet microvesicles concentrations may induce beneficial microvascular adaptations as suggested by previous research.
- flow mediated dilation
- shear rate
- endothelial function
- Copyright © 2016, Journal of Applied Physiology