Why is a person with high blood pressure asked to reduce salt!

Humans ingest sodium by eating salt in food and occasionally in medications. Most people will simply excrete excess sodium in the urine, and we also lose sodium and water through perspiration. But about 20 percent of the population has a genetic characteristic that causes sodium retention, which results in water retention, and can increase blood pressure. Eating salt also makes people thirsty, which means they tend to drink more, and this makes the situation worse. Too much salt keeps the amount of fluid circulating in the body higher than it should be, which means increased pressure on the blood vessel walls. The walls thicken and narrow under the continued high pressure, and the heart must pump harder to move fluid around. This increased work makes the heart muscle larger and increases the force of each contraction; the higher pressure damages the blood vessels—and the filtration system—in the kidneys and raises blood pressure.