Effects Of Interrupting Prolonged Sitting With Different Exercise Modes On Vascular Function In Healthy Adults

While interrupting prolonged sitting with aerobic exercise has been demonstrated to attenuate endothelial dysfunction and postprandial metabolism, less is known about the effect of interrupting prolonged sitting with resistance exercise. PURPOSE: to compare the effects of resistance exercise and aerobic exercise as a strategy for interrupting prolonged sitting on vascular function after a high-fat meal in healthy adults. METHODS: Using a randomized crossover study design, fourteen healthy young adults (8 males, 24 ± 2 yrs, BMI: 22.0 ± 2.4 kg/m2) participated all three trials. Participants performed either aerobic exercise (AE, 5 minutes of step-exercise every hour), resistance exercise (RE, 5 minutes of resistance exercise every hour), or seated uninterrupted (SIT) during 4-hour sitting, following a high-fat meal. Blood flow and shear rate in superficial femoral artery and carotid artery, oscillatory shear index, plasma glucose and triglycerides were measured at baseline and every hour after a high-fat meal, while brachial artery flow-mediated dilation (FMD) was measured at baseline and at 2- and 4-hour after a high-fat meal. RESULTS: FMD significantly decreased following a 4-hour uninterrupted sitting (SIT: 7.4 ± 0.7% to 6.4 ± 0.7% to 5.0 ± 0.7%), while both AE and RE attenuated sitting-induced endothelial dysfunction without significant interaction effect (AE: 7.8 ± 0.7% to 7.0 ± 0.7% to 7.3 ± 0.7%, RE: 7.5 ± 0.7% to 7.3 ± 0.6% to 6.7 ± 0.7%). Superficial femoral artery blood flow and mean shear rate increased in AE and RE compared to SIT (interaction p < 0.001, p = 0.009, respectively). AE increased blood flow and mean shear rate more and had lower oscillatory shear index in superficial femoral artery than RE. CONCLUSIONS: These findings have provided evidence that interrupting prolonged sitting after intake of a high-fat meal with either aerobic and resistance exercise was effective in improving basal blood flow and shear rate in the lower-limb artery in young health adults, with a greater benefit observed with aerobic exercise.