The Effects of an Acute High NaCl Diet on the Measurement of Limb Venous Compliance

Authors

Michael J. Nolan, Southern Illinois University CarbondaleFollow

Degree Name

Master of Science in Education

Graduate Program

Kinesiology

Advisor

Wallace, Juliane P.

Abstract

Calf venous compliance improves with aerobic training and declines with age. Individuals with hypertension often have decreased arterial and venous compliance. Acute high consumption of NaCl may increase net transcapillary fluid filtration in the limbs, but it is unknown if this acutely high NaCl intake will alter non-invasive assessment of calf venous compliance. In humans, assessment of limb venous compliance is generally performed using venous occlusion plethysmography; however, there is no standard recommendation for pre-assessment food consumption and it remains unknown if acute high NaCl intake will affect limb venous compliance measures in humans. PURPOSE: To determine if acute high NaCl consumption will alter measures of calf venous compliance using venous occlusion plethysmography. METHODS: Ten healthy college aged males (22.5 ± .99163 yrs, 33.66 ± 3.07386 ml*kg^-1*min^-1) participated in this study, and underwent assessment of calf venous compliance following random assignment of either 12 hours of fasting or consumption of 3055 ± 68.77 mg of NaCl in the 12 hours prior to testing. Utilizing venous occlusion plethysmography, limb venous compliance was determined in both trials using the first derivative of the pressure-volume relationship during cuff pressure reduction. Compliance was compared as the slope of the compliance-pressure relationship. Data were analyzed using a paired sample t-test. RESULTS: There were no significant differences in calf venous compliance (β₀ = .5741 ± .21760 β₁ = .0781 ± .01165 β₂ = -.0005 ± .00011 vs. β₀ = .5674 ± .40101 β₁ = .0830 ± .01209 β₂ = -.0006 ± .00012), capacitance (1.7844 ± .12761 vs. 1.864 ± .13723 ml) or capillary filtration (0.7346 ± .09415 vs. 0.7028 ± .07804 ml) volumes between the fasted and acute NaCl intake conditions. CONCLUSION: These data suggest that calf venous compliance assessment using venous occlusion plethysmography is not affected by acute high NaCl consumption.