Background: Whole-body exercise provides protection against endothelial ischaemia-19 reperfusion (IR) injury. In this crossover study, we examined the effects of 1) single bout of 20 local exercise (handgrip, squats) on endothelial responses to IR, and 2) if 7 days of daily local 21 exercise bolsters these effects in individuals with cardiovascular disease (CVD) risk factors. 22 Methods: Fifteen participants (9 women, 58±5 years, ≥2 CVD risk factors) attended the 23 laboratory for 6 visits. Subsequent to familiarization (visit 1), on visit 2 (control) brachial 24 artery flow-mediated dilation (FMD) was measured before and after IR (15-minutes upper-25 arm ischemia, 15-minutes reperfusion). One week later, participants were randomized to 4x5-26 min unilateral handgrip (50% maximal voluntary contraction, 25 rpm) or squat exercises (15 27 rpm), followed by IR plus FMD measurements. Subsequently, home-based exercise was 28 performed (six days), followed by another visit to the laboratory for the IR protocol plus 29 FMD measurements (18-24 h after the last exercise bout). Following a two-week washout 30 period, procedures were repeated with the alternative exercise mode. 31 Results: For a single exercise bout, we found a significant IR injury*exercise mode 32 interaction (P<0.01), but no main effect of injury (P=0.08) or condition (P=0.61). A lower 33 post-IR FMD was evident after control (pre-IR: 4.3±2.1% to post-IR: 2.9±1.9%, P<0.01), but 34 not after handgrip (pre-IR: 3.8±1.6% to post-IR: 3.4±1.5%, P=0.31) or squats (pre-IR: 35 3.9±1.8% to post-IR: 4.0±1.9%, P=0.74). After 7 days of daily exercise, we found no change 36 in FMD post-IR following handgrip (pre-IR: 4.3±1.9% to post-IR: 4.7±3.2%) or squats (pre-37 IR: 3.7±2.1% to post-IR: 4.7±3.0%, P>0.05). 38 Conclusions: Single bouts of dynamic, local exercise (handgrip, squats) provides remote 39 protection against endothelial IR-induced injury in individuals with CVD risk factors, with 40 one-week daily, home-based exercise preserving these effects for up to 24h following the last 41 exercise bout.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)