Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA016

Poster Communications

Potassium intake reduces the elevated blood pressure response to oral salt loading as well as to voluntary hand grip in normotensive adult Nlgerians.

I. Awodele1, O. Sofola2

1. Physiology, Babcock University, Ilishan, Nigeria. 2. Physiology, College of Medicine, University of Lagos, Lagos, Nigeria.

Oral salt loading has been shown to result in elevated blood pressure especially in salt sensitive normotensive subjects (Elias et al, 2011), while voluntary hand grip contraction increases blood pressure via activation of sympathetic nervous system (Fadel et al, 2003). However dietary potassium supplement can reduce arterial blood pressure (Gijsbers et al, 2015). The present study was designed to determine if potassium intake can ameliorate the pressor response to high salt ingestion as well as to hand grip contraction. Experiments were carried out on 30 normotensive (NT) students of Babcock University, aged 25.3±0.92 yrs (Mean±SEM), that were divided into two groups of 15 subjects each : a) salt loaded with 200 mmol sodium chloride solution for 5 days (Elias et al, 2011) and b) salt loaded for 5 days with added intake of 600 mg of potassium chloride tablets (Slow K®, Novartis). Further tests were also carried out in both groups, before and during Hand Grip (HG) at 30% of Maximum Voluntary Contraction (MVC) for one minute with the use of a Dynamometer (Camry, Model EH101). Ethical Approval was obtained from Babcock University Research and Ethics committee and the subjects gave written consent. Blood pressure (BP, mmHg) was measured with an Accoson sphygmomanometer and also serum Na+ and K+ concentrations (mmol/l) before and after administration of salt or salt + potassium (salt+K). The effects of 30% MVC hand grip were also determined in the two groups of subjects. Data are Mean±SEM and statistical analysis was by Students paired t test. The results show that salt intake resulted in significant elevation of Systolic Blood Pressure (SBP), from baseline of 118.3±1.8 to 123.5±1.9 (P<0.05) but not of diastolic Blood Pressure (DBP)- 65.3±1.3 vs 67.2±1.4 (P=NS). However, after salt+K, the BP change was reversed and SBP reduced significantly from 122.6±1.5 to 117.2±1.2 (P<0.05) and DBP from 70.0±1.9 to 62.1±1.5 (P<0.05). Salt intake increased serum Na+ concentration significantly from 133.9±0.7 to 138.6±0.9 (P<0.05) but Salt+K however reduced it from 139.1±0.5 to 136.6+0.3 (P<0.05). However serum K+ was not significantly altered either by salt or salt+K. HG significantly increased (P<0.05) SBP from 127.6±2.9 to 157.2±2.6 in controls, less so from 126.9±1.7 to 149.9±3.8 in salt loaded subjects but had no significant effect in subjects on salt+K ie 124.0±3.0 vs 127.9±2.1. During HG, DBP increased in controls from 76.9±2.5 to 95.6±2.9 (P<0.05) and after salt loading, from 75.4±2.8 to 84.7±2.2 (P<0,05) but in salt+K, there was no significant change - 82.8±2.0 vs 79.5±1.7. The results indicate that potassium intake blunts the BP elevation following salt loading or during voluntary HG. Potassium intake may therefore be effective in reducing induced changes in blood pressure.

Where applicable, experiments conform with Society ethical requirements