Moderate to intense exercise may protect the brain

Older people who regularly exercise at a moderate to intense level may be less likely to develop the small brain lesions, sometimes referred to as "silent strokes," that are the first sign of cerebrovascular disease, according to a new study published in the June 8, 2011, online issue of Neurology.

13 june 2011--"These 'silent strokes' are more significant than the name implies, because they have been associated with an increased risk of falls and impaired mobility, memory problems and even dementia, as well as stroke," said study author Joshua Z. Willey, MD, MS, of Columbia University in New York and a member of the American Academy of Neurology. "Encouraging older people to take part in moderate to intense exercise may be an important strategy for keeping their brains healthy."

The study involved 1,238 people who had never had a stroke. Participants completed a questionnaire about how often and how intensely they exercised at the beginning of the study and then had MRI scans of their brains an average of six years later, when they were an average of 70 years old.

A total of 43 percent of the participants reported that they had no regular exercise; 36 percent engaged in regular light exercise, such as golf, walking, bowling or dancing; and 21 percent engaged in regular moderate to intense exercise, such as hiking, tennis, swimming, biking, jogging or racquetball.

The brain scans showed that 197 of the participants, or 16 percent, had small brain lesions, or infarcts, called silent strokes. People who engaged in moderate to intense exercise were 40 percent less likely to have the silent strokes than people who did no regular exercise. The results remained the same after the researchers took into account other vascular risk factors such as high blood pressure, high cholesterol and smoking. There was no difference between those who engaged in light exercise and those who did not exercise.

"Of course, light exercise has many other beneficial effects, and these results should not discourage people from doing light exercise," Willey said.

The study also showed that the benefit of moderate to intense exercise on brain health was not apparent for people with Medicaid or no health insurance. People who exercised regularly at a moderate to intense level who had Medicaid or no health insurance were no less likely to have silent infarcts than people who did no regular exercise. "It may be that the overall life difficulties for people with no insurance or on Medicaid lessens the protective effect of regular exercise," Willey said.

Provided by American Academy of Neurology

Eating Fish May Protect Against Silent Brain Infarcts

By Todd Neale
KUOPIO, Finland, 06 aug 2008-- Older patients who ate at least three servings of fish a week had a decreased risk of certain subclinical brain abnormalities, researchers found. Patients 65 and older who ate the most tuna or other fish high in omega-3 fatty acids tended to have a 26% reduced risk of silent infarct compared with those eating less than one serving a month (RR 0.74, 95% CI 0.54 to 1.01, P=0.06), Jyrki Virtanen, Ph.D., of the University of Kuopio, and colleagues reported in the Aug. 5 issue of Neurology. In addition, those who ate the most fish had 10.6% better white matter grade scores compared with those who ate the least (P=0.003) after adjusting for various risk factors.
The associations did not apply to consumption of fried fish, most likely because the types of fish usually fried -- for example, cod and pollock -- have low levels of omega-3 fatty acids.
Although fish consumption has been linked to risk of clinical stroke, whether eating fish affects the risk of subclinical brain abnormalities -- which are associated with cognitive and neurobehavioral impairments and risk of future stroke -- is unknown, the researchers said.
To address the question, they turned to the Cardiovascular Health Study, conducted in four U.S. communities. They looked at data for 3,857 participants ages 65 and older who underwent at least one MRI scan; 2,116 of them underwent two scans five years apart.
All were free from clinical transient ischemic attack or stroke.
Fish consumption was measured using food frequency questionnaires, one administered at enrollment in 1989-1990 and the other during follow-up in 1995-1996.
Higher consumption of tuna or other broiled or baked fish was associated with younger age, female sex, higher education, lower systolic blood pressure, higher LDL and HDL cholesterol, higher ankle-arm index, higher energy intake, higher fruit and vegetable consumption, and lower saturated fat intake (P<0.05 for all).
On the first MRI, 23% of the participants showed at least one subclinical infarct, and on the second the prevalence was 23.1%.
For each additional serving of tuna or other non-fried fish consumed per week, the risk of subclinical infarct was reduced by 7% (P=0.03 for trend).
Among patients who had two scans performed, 16.6% had at least one new silent infarct between the two scans.
There was a nonsignificant trend toward a lower incidence of silent infarcts for those who ate the most fish. The lack of statistical significance was possibly related to limited power, the researchers said.
Fish consumption was not associated with sulcal or ventricular grades, markers of brain atrophy (P>0.10 for both).
Because consumption of fish or omega-3 fatty acids has also been associated with reduced risk of dementia and Alzheimer's disease in other studies, the researchers said, "our findings suggest that prevention of subclinical infarcts and white matter abnormalities may be one mechanism whereby fish or [omega-3 fatty acid] consumption may decrease the development of these debilitating conditions."
The authors acknowledged some limitations of the study, including the fact that participants who underwent MRI scans were healthier than those who did not, which might reduce the generalizability of the findings to the entire older population.
In addition, estimates of sulcal grade have high rates of inter-reader variability, the second food frequency questionnaire did not have information on fried fish consumption, estimating omega-3 fatty acid intake by questionnaire could have resulted in some exposure misclassification, and the food frequency questionnaires and MRI were not administered at the same time.
Finally, the associations could have been the result of other factors related to fish consumption, such as a healthier lifestyle.
Nevertheless, the researchers said, "our results support the need for randomized trials of fish or fish oil intake to reduce subclinical ischemic events, which would be feasible and important given the high incidence of such events in older adults."
The study was supported by contracts from the National Heart, Lung, and Blood Institute, by the National Institute of Neurological Disorders and Stroke, and by grants from the Finnish Cultural Foundation, Helsingin Sanomar Centennial Foundation, Finnish Foundation for Cardiovascular Research, Yrjo Jahnsson Foundation, and University of Kuopio.
The authors made no disclosures.
Primary source: NeurologySource reference:Virtanen J, et al "Fish consumption and risk of subclinical brain abnormalities on MRI in older adults" Neurology 2008; 71: 439-446.