Drinking Water May Raise Blood Pressure Of ‘Millions’

High blood pressure is sometimes called a “silent killer” because, while it increases your risk of heart conditions, stroke, and cardiac arrest, it often has no symptoms.

About five million people in the UK are believed to have undiagnosed high blood pressure, the British Heart Foundation said.

Also known as hypertension, the condition can be brought about or worsened by high levels of salt in your diet, smoking, inactivity, and stress.

But a meta-analysis published in the BMJ Global Health found that drinking water – especially among coastal communities – was potentially adding to millions of people’s salt intake without them realising, thus raising their risk of high blood pressure.

“As sea levels rise, more and more salt water tends to infiltrate global freshwater sources,” study author Dr Rajiv Chowdhury said.

This is called “saltwater intrusion”, which especially affects a lot of low-lying countries like Vietnam and Bangladesh, though it’s a global problem.

This meta-analysis looked at 27 observational studies, including 74,000 participants from countries including the US, Australia, Bangladesh, Vietnam, Kenya, and various European countries.

A separate study found that European estuaries are at increased risk of saltwater intrusion, which is a global phenomenon.

The BMJ research showed that those who drank saltier water had higher blood pressure, on average. In fact, risk rose by 26% – and was highest among coastal populations.

Writing for The Conversation, Dr Chowdhury pointed out that the World Health Organisation currently has no guidelines for water salinity (saltiness).

But his research suggests that the metric could have serious health outcomes for “millions” of people.

Over three billion people live on or near the coast globally.

Physical inactivity raises hypertension risk by anything from 15-25%, Dr Chowdhury added.

His research suggested that drinking salty tap water could raise your likelihood of developing high blood pressure by 26%. That means “the risk that higher water salinity levels poses to hypertension is similar to that of other cardiovascular risk factors, such as low physical activity.”

While a lot of blood pressure advice focuses on lifestyle changes, perhaps this might mean people who are otherwise making great decisions are unwittingly facing much higher risk.

“More research is needed to examine connections with CHD and stroke, and to create strategies to counter salinity’s effects, particularly in climate-vulnerable coastal areas,” the study concluded.

Digital salinity meters are commercially available if you have concerns.