Influence of Short‐term High Salt Diet and Acute Exercise on Microvascular Reactivity in Humans

Abstract

High salt diet contributes to the development of hypertension. The deleterious effects of high salt diet (HSD) may occur independent of and prior to the development of high blood pressure. We hypothesized that 1) microvascular flow induced dilation (FID) and acetylcholine induced dilation (AChID) are impaired after short‐term HSD and 2) acute exercise reverses endothelial function after short term salt loading. Healthy, inactive woman (N=15) were fed 6 g of NaCl for 7 days and then underwent a single progressive 15 min leg press WL session. Subcutaneous fat tissue biopsies were obtained before and after HSD and acute exercise. Resistance arteries from biopsies were cannulated for vascular reactivity measurements in response to flow (pressure gradient 10–100 cmH2O) and in response to acetylcholine (ACh, 10–9‐10–4 M). All subjects were normotensive before and urinary sodium was increased after HSD and exercise. Plasma renin activity and plasma aldosterone levels were reduced after HSD. FID and AChID were reduced after 7 days of HSD compared to pre‐HSD. Acute exercise restored FID and AChID post HSD. The presence of L‐NAME reduced FID and AChID at baseline and after exercise. However, there was no effect of L‐NAME on FID and AChID after HSD. These data suggest that 1) one week of HSD impairs microvascular FID and AChID and 2) acute exercise restores microvascular NO‐dependent dilation to flow and ACh.