Isometric handgrip training does not improve flow-mediated dilation in persons with normal blood pressure. Clin Sci 2007a

A B S T R A C T Isometric HG (handgrip) training lowers resting arterial BP (blood pressure), yet the mechanisms are elusive. In the present study, we investigated improved systemic endothelial function as a mechanism of arterial BP modification following isometric HG training in normotensive individuals. This study employed a within-subject repeated measures design primarily to assess improvements in BA FMD (brachial artery flow-mediated dilation; an index of endothelium-dependent vasodilation), with the non-exercising limb acting as an internal control. Eleven subjects performed four 2-min unilateral isometric HG contractions at 30 % of maximal effort, three times per week for 8 weeks. Pre-, mid-and post-training resting ABP and BA FMD (exercised arm and non-exercised arm) were measured via automated brachial oscillometry and ultrasound respectively. BA FMD (normalized to the peak shear rate experienced in response to the reactive hyperaemic stimulus) remained unchanged [exercised arm, 0.029 + − 0.003 to 0.026 + − 0.003 to 0.029 + − 0.004 %/s −1 (preto mid-to post-training respectively); non-exercised arm, 0.023 + − 0.003 to 0.023 + − 0.003 to 0.024 + − 0.003 %/s −1 (pre-to mid-to post-training respectively); P = 0.22]. In conclusion, improved systemic endothelial function is unlikely to be responsible for lowering arterial BP in this population