Effect of acute walking on endothelial function and postprandial lipemia in South Asians and White Europeans

Introduction: South Asians (SAs) have an elevated risk of cardiovascular disease (CVD) compared with White Europeans (WEs). Postprandial endothelial function (flow-mediated dilatation (FMD%)) in SA women and SA men with central obesity has not been investigated. Research in other populations has highlighted that a 1% higher FMD% is associated with a ~13% lower risk of future CVD events. We investigated whether FMD% and lipemia, two markers for CVD risk, were higher in SAs versus WEs, whether walking improved FMD% and lipemia, and if there were ethnic differences in the response.

Methods: Lean premenopausal women (study 1; 12 SA, 12 WE) and men with central obesity (study 2; 15 SA, 15 WE) completed two 2-d trials. On day 1, participants walked for 60 min at 60% of their peak oxygen uptake or rested. On day 2, participants rested and consumed two high-fat meals over 8 h. Repeated ultrasound assessments of endothelial function and venous blood samples for CVD risk markers were taken.

Results: Compared with WEs, SAs had lower postprandial FMD% (study 1, −1.32%; study 2, −0.54%) and higher postprandial triacylglycerol concentrations (study 1, 0.31 mmol·L⁻¹·h⁻¹; study 2, 0.55 mmol·L⁻¹·h⁻¹). Walking improved postprandial FMD% (study 1, 1.12%; study 2, 0.94%) and resulted in no significant change or small reductions in postprandial triacylglycerol concentrations (study 1, −0.01 mmol·L⁻¹·h⁻¹; study 2, −0.25 mmol·L⁻¹·h⁻¹). Exercise-induced changes in FMD% and triacylglycerol were consistent between ethnic groups.

Conclusions: Walking mitigated the adverse postprandial effect of a high-fat diet on FMD% to a similar extent in SA and WE women and men, even with no/small improvements in triacylglycerol. This study highlights the importance of exercise to clinically improve FMD% in SAs and WEs.