It shows for the first time that vigorous exercise in early adulthood is an independent protective factor against a stroke, the leading cause of death in developed countries.
It suggests that 'ageing begins young', and that, although strokes are associated with age, a person's risk appears to be determined in part by what he or she did between the ages of 15 and 25.
Each year 100,000 people in Britain suffer a stroke, a quarter of them under the age of 65. The risk increases with age and the incidence is higher in men than women. A proportion make a full or partial recovery but many people are left permanently disabled by the disease, are unable to work and require full-time care lasting for years.
Researchers from Birmingham University studied 105 men and women between the ages of 35 and 74 who had suffered their first stroke, and 161 matched controls. They used a questionnaire to divide the group into those who did or did not take part in regular, vigorous activity when aged 15-25 (youth), 25-40 (early middle-age), and 40-55 (late middle-age). The types of exercise included digging, running, squash, swimming, cycling, squash, tennis and keep-fit or walking.
The report, in tomorrow's issue of the British Medical Journal, says: 'Among the 105 cases and 161 controls aged over 54, an increasing protection from stroke was seen as the duration of exercise in earlier years increased. This trend was highly significant.'
People who were most active as young adults were more likely to continue with exercise in later life. Social class was also a factor, the researchers said. Higher social class is linked to a decreased risk of a stroke, and people who stayed on at school were more likely to have carried on with regular sports in their youth.Reuse content