Hourly staircase sprinting exercise snacks improve femoral artery shear patterns but not flow-mediated dilation or cerebrovascular regulation: a pilot study

Healthy males (n = 10; age: 24 +/- 4 years; bodymass index: 24 +/- 2 kg.m(-2)) completed 2 randomized conditions separated by >= 48 h involving 6-8.5 h of sitting with (stair snacks) and without (sedentary) hourly staircase sprint interval exercise (similar to 14- 20 s each). Resting blood flow and shear rates were measured in the femoral artery, internal carotid artery, and vertebral artery (Duplex ultrasound). Flow-mediated dilation (FMD) was quantified as an index of peripheral endothelial function in the femoral artery. Neurovascular coupling (NVC; regional blood flow response to local increases in cerebral metabolism) was assessed in the posterior cerebral artery (transcranial Doppler ultrasound). Femoral artery hemodynamics were higher following the active trial with no change in the sedentary trial, including blood flow (+32 +/- 23% vs. -10 +/- 28%; P = 0.015 and P = 0.253, respectively), vascular conductance (+32 +/- 27% vs. -15 +/- 26%; P = 0.012 and P = 0.098, respectively), and mean shear rate (+17 +/- 8% vs. -8 +/- 28%; P = 0.004 and P = 0.310, respectively). The change in FMD was not different within or between conditions (P = 0.184). Global cerebral blood flow (CBF), conductance, shear patterns, and NVC were not different within or between conditions (all P > 0.05). Overall, exercise stair snacks improve femoral artery blood flow and shear patterns but not peripheral (e.g., FMD) or cerebral (e.g., CBF and NVC) vascular function following prolonged sitting. Novelty: Breaking up 8.5 h of sitting with hourly staircase sprinting exercise snacks improves resting femoral artery shear patterns but not FMD. Cerebral blood flow and neurovascular coupling were unaltered following 6 h of sitting with and without hourly exercise breaks.

Automated summary

The study showed that stair snacks exercise can improve femoral artery blood flow and shear patterns, but does not have a significant impact on peripheral and cerebral vascular function.