Nowhere in medicine is there more confusion than the issue of salt as a cause of high blood pressure. At a recent meeting of the American Association of Clinical Endocrinologists, Dr. Abdul-Rahman of Newark, Delaware reported that people who lowered blood insulin levels had a significant reduction in high blood pressure even though they also markedly increased their salt intake. Journal reference
These obese patients increased their daily salt intake from less than two grams a day to more than 20 grams a day. They avoided starchy and sugary foods and lost around 12 pounds in six weeks. They did not count calories. Their average blood sugars dropped from 106 to 98, average fasting insulin from 21 to 14 mu/ml and average diastolic blood pressure from 96 to 88. Some of the patients were able to stop their blood pressure drugs. This study and others show that high blood insulin levels are an important cause of high blood pressure, and that you can lower insulin levels by avoiding refined carbohydrates and losing weight. Instead of salt restriction, I recommend a modified DASH diet to all my patients.
Exercisers need salt, particularly in warm weather. When you exercise for more than three hours, you should take in salt as well as fluids. Taking in fluid without also taking in adequate amounts of salt dilutes the bloodstream, so that the concentration of salt in the blood is lower than that in brain cells. This causes fluid to move from the low-salt blood into the higher-salt brain causing the brain to swell which can cause seizures and death. Taking in extra salt during prolonged exercise increases thirst so you drink more fluids, and prevents blood salt levels from dropping so low that you become tired, develop muscle cramps, and can even die. Furthermore, without salt you do not recover as quickly and are more likely to be injured or tired all the time. More on hyponatremia