You've probably heard doctors advise people with heart disease to reduce their salt intake. But what is the medical reason behind this?

The heart acts as the body's pump, circulating blood throughout the body.

If, for any reason, the total volume of blood in the body increases significantly, the heart has to pump a larger amount of blood with every beat.

For a person with heart disease, the heart may struggle to cope with this extra workload.

In someone with high blood pressure (hypertension), the heart is already pumping blood against increased resistance. If the blood volume rises further, the pressure can increase even more, making it harder for the heart to pump effectively.

Similarly, in a person who has had a heart attack (myocardial infarction) or has heart failure, forcing the heart to work harder under these conditions can worsen the existing disease.

So, an increase in total blood volume is not beneficial for the heart. But what does salt have to do with this?

About 60% of the human body is made up of water, but only about 5% of that water is present in the bloodstream. Most of the body's water is actually stored inside cells.

Salt, or sodium chloride (NaCl), has the ability to draw water from inside the body's cells into the blood vessels. As a result, the volume of blood circulating in the body increases, placing additional strain on the heart and potentially worsening heart conditions.

For this reason, no matter how much you enjoy salty foods, limiting your salt intake is an important step in keeping your heart healthy and reducing the risk of complications from heart disease.