Potassium moderates the rise in blood pressure during mental stress by reducing the effect of adrenaline. Potassium is also needed for protein synthesis, carbohydrate metabolism, and insulin secretion by the pancreas. Potassium deficiency causes no symptoms, but can induce an increase in fluid volume and impair blood pressure regulating mechanisms. It may also aggravate existing heart disease. More severe deficiency can result in nausea, vomiting, diarrhoea, muscle cramps, muscle weakness, poor reflexes, poor concentration, heart arrhythmias.