White matter - the part of the brain consisting of connecting nerve fibres - affects a person's ability to keep balance and stay upright in old age, research has shown.
The study, published in Neurology, the medical journal of the American Academy of Neurology, shows that people with severe white matter changes are twice as likely to score poorly on walking and balance tests as people with mild white matter changes.
The three-year study, co-ordinated by the department of neurological and psychiatric sciences of the University of Florence, involved volunteers between the ages of 65 and 84 who underwent brain scans and walking and balance tests.
"Walking difficulties and falls are major symptoms of people with white matter changes and a significant cause of illness and death in the elderly," said the study author, Hansjoerg Baezner of the University of Heidelberg in Mannheim, Germany.
"Exercise may have the potential to reduce the risk of these problems since exercise is associated with improved walking and balance."