Researchers at Columbia University have established that moderate to intense exercise by the elderly may reduce by 40% their risk of developing brain lesions (or so called silent strokes).
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.
So is the effect the exercise, or the willingness to take care of themselves? The effect was more tied with medical coverage than exercise as people who exercise but only have Medicaid or no health insurance don't have the same benefit. Coupled with:
This makes me believe it less. Are we to believe these have no effects on brain health? It is possible, but unlikely. This tells me the methodology wasn't very sensitive.
I think a possible interpretation of the results is that people need health care access and a willingness to use it to stay healthy.
I think the operative word is MAY. I don't think the researchers are claiming that the results prove anything absolutely.
So far as the lessened risk not occurring in subjects with no health insurance or on Medicaid you have already pointed out that one of the researchers said:
"It may be that the overall life difficulties for people with no insurance or on Medicaid lessens the protective effect of regular exercise,"
It is no secret that stress can adversely affect one's health. It might have nullified the benefits of exercise in this study.
Regarding high blood pressure and high cholesterol you said:
"Are we to believe these have no effects on brain health?"
Perhaps they have nothing to do with brain lesions.
I find it interesting that the lower risk of lesions was only associated with moderate to intense exercise and not light exercise. I say this because I suspect that the people in the study who did only light exercise nonetheless on average had better general health habits than those who did none. That is, if they had better general health habits than those who did none then, in that there was no lower risk for them, it would be more likely that the lower risk in the moderate to intense exercise group was not associated with health habits in general but with reaching a particular threshold of exercise intensity.
Nobody is saying that the study absolutely proves anything. It has been published in a peer reviewed journal on the grounds that it demonstrates moderate to intense exercise may reduce the risk of brain lesions in the elderly.