People who drink more water appear to live longer and develop fewer chronic diseases, a study suggests.
Using health data gathered from 11,255 adults over 30 years, researchers analysed links between serum sodium levels – which go up when fluid intake goes down – and various indicators of health.
They found adults with serum sodium levels at the higher end of a normal range were more likely to develop chronic conditions and show signs of advanced biological ageing than those with levels in the medium ranges.
Adults with higher levels were also more likely to die younger, the researchers said.
The peer-reviewed findings of the National Institutes of Health (NIH), a US medical research agency, were published in the eBioMedicine journal on Monday.
“The results suggest that proper hydration may slow down ageing and prolong a disease-free life,” said Natalia Dmitrieva, study author and researcher at the Laboratory of Cardiovascular Regenerative Medicine at the National Heart, Lung and Blood Institute (NHLBI), part of NIH.
NHS recommends six to eight drinks a day
The authors did not define “proper hydration”, but according to NHS England people should have six to eight drinks a day, which can include water, lower-fat milks, tea and coffee.
In March, the scientists published a study which found links between higher ranges of normal serum sodium levels and increased risk of heart failure.
For the new study, they assessed information participants shared during five medical visits – the first two when they were in their 50s and the last when they were between 70 and 90.
They excluded adults who had high levels of serum sodium at baseline check-ins or with underlying conditions, like obesity, which could affect serum sodium levels.
They then evaluated how the levels correlated with biological ageing, which was assessed through 15 health markers.
They included factors such as systolic blood pressure, cholesterol and blood sugar, which provided insight about how well each person’s cardiovascular, respiratory, metabolic, renal and immune system was functioning.
They also adjusted for factors like age, race, biological sex, smoking status and hypertension.
They found adults with higher levels of normal serum sodium – with normal ranges falling between 135-146 milliequivalents per litre (mEq/L) – were more likely to show signs of faster biological ageing.
This was based on indicators like metabolic and cardiovascular health, lung function and inflammation, they said.