Keeping fit as a teenager can halve the risk of heart attacks much later in life, a study has found.
Every 15pc increase in fitness at the age of 18 cuts the chances of a heart attack 30 years later by almost a fifth, according to scientists who studied data on more than 743,000 young national service conscripts in Sweden.
But the study also showed that fitness could not counteract the effects of being overweight or obese, which greatly increased the risk of a heart attack.
All the participants underwent fitness tests at the age of 18 prior to entering the Swedish armed forces between 1969 and 1984, before Sweden dropped compulsory national service in 2010.
Each 18-year-old conscript had a full medical examination which included being tested for stamina on an exercise cycle. The recruits were then monitored for an average period of 34 years, during which all cases of heart attack or death were recorded.
A clear association was reported between fitness levels at the age of 18 and the chances of having a heart attack years later.