Encouraging older people to engage in moderate to intense exercise may protect their brains from small lesions also known
as "silent strokes", according to a new study that appeared online in the journal Neurology this week. However, the study
did not find this benefit in people on Medicaid or with no health insurance, implying that a life of hardship erodes it.
Although they are the first sign of cerebrovascular disease, infarcts or "silent strokes" are often overlooked because people who have them don't experience the more well-known signs and symptoms of major stroke, such as severe headache, dizziness, inability to smile, drooping side of face or eye, inability to lift one or both arms, and slurred or garbled speech.
Corresponding study author Dr Joshua Z. Willey, of Columbia University in New York and member of the American Academy of Neurology, told the press that although these lesions are called "silent strokes", their occurrence is more significant than the term implies, because they are linked to a higher risk of falls, memory problems, impaired mobility, and even dementia, as well as stroke.
"Encouraging older people to take part in moderate to intense exercise may be an important strategy for keeping their brains healthy," he urged.
For the study, the researchers examined data from the population-based prospective cohort for the Northern Manhattan Study (NOMAS), which is examining stroke and stroke risk factors in the Northern Manhattan community.
Their sample came from 1,238 participants who had filled in questionnaires at the start of the study and an average of about 6 years later had undergone MRI scans of their brains and had never had a stroke. The questions included some that had asked them how often and how intensely they exercised.
The results showed that:
- 43% of the participants reported doing no regular exercise.
- 36% reported engaging in regular exercise: for example playing golf, walking, bowling, dancing.
- 21% reported doing moderate to intense exercise on a regular basis, including hiking, tennis, biking, jogging, swimming and racquetball.
- The MRI scans showed that 16% (197 participants) had small brain lesions or "silent stroke" infarcts.
- The participants who reported regularly doing moderate to intense exercise were 40% less likely to be among those whose MRI showed signs of these brain lesions than participants who reported having no regular exercise.
- The link remained after taking into account other risk factors for stroke such such as smoking, high blood pressure, and high cholesterol.
- There was no difference in risk between those who reported doing light exercise and those who said they did none.
"Engaging in moderate to heavy physical activities may be an important component of prevention strategies aimed at reducing subclinical brain infarcts."
However, Willey stressed these results should not put people off doing light exercise, which clearly has other benefits.
The researchers also found there was no link between moderate to intense exercise and reduced risk of silent stroke in people who had Medicaid or no health insurance.
Willey said perhaps this showed that the "overall life difficulties for people with no insurance or on Medicaid lessens the protective effect of regular exercise".
Funds from the National Institute of Neurological Disorders and Stroke helped pay for the study.
"Lower prevalence of silent brain infarcts in the physically active: The Northern Manhattan Study."
J.Z. Willey, Y.P. Moon, M.C. Paik, M. Yoshita, C. DeCarli, R.L. Sacco, M.S.V. Elkind, and C.B. Wright
Neurology Published ahead of print 8 June 2011
Additional source: American Academy of Neurology.
Written by: Catharine Paddock, PhD