Discussion: Aerobic Exercise Delays Dementia

Two recent studies at the Cooper Institute in Texas and in New Zealand have found that for seniors, fitness and aerobic exercise could actually DELAY and IMPROVE cognitive functions, whereas walking, yoga, stretching, and less vigorous exercise did nothing:

...Studies in older adults...consistently found that fitter individuals scored better in mental tests than their unfit peers. In addition [scores improved for folks assigned] to an aerobic exercise regimen compared to those assigned to stretch and tone classes...[so] it is not only the body which benefits from exercise, but the mind too...

Interestingly similar benefits were not found for younger folks. And the amount of aerobic exercise needed was not quantified by the studies. Certainly those with higher BMI's and classified as "overweight" can be aerobic. But do they attain their aerobic threshold consistently? Isn't this yet another finding to question the recent controversial study that claimed heavy people with higher BMI's lived longer?

The message is clear: Fat or thin, if you wish to ensure the highest quality of life in your senior years, you must get that heart rate up for sustained periods on a very regular basis, probably beginning in your 40's.

Niggling concern about the direction of causality. There may be some running the other way as well. The intervention studies explain the obvious direction, but education and class relationships with exercise might be working in here as well.

My cognitive functions have always been slow enough that I feel no need to further DELAY them. Did the studies mention when walking ceased to be considered an aerobic exercise?

...I think the study showed that aerobic exercise delayed the ONSET of dementia in seniors. And in the more comprehensive Cooper Institute study, researchers studied

...more than 19,000 generally healthy men and women who completed a preventive medical exam at Cooper Clinic when they were, on average, 49 years of age. The exam also included other health risk factors such as body mass index (BMI), blood pressure, and cholesterol. Their health status was evaluated an average of 24 years after their Cooper Clinic examination.
“The exercise we do in middle-age is relevant for not only how long we live, but also how well we live, [and shows] the value of lifelong exercise and its protection against dementia in older age,”

How is it that we're talking about dimensia when we could be talking about sperm?

I should probably have put a smiley face in my comment about delay of cognitive function--I was just making a joking reference to your initial comment where you had referred to " could actually DELAY and IMPROVE cognitive functions", when you clearly meant to DELAY dementia and IMPROVE cognitive functions. My other comment about not including walking as an aerobic exercise was more serious, since walking was actually referred to as one of the aerobic exercises considered in one of the studies, and walking is normally considered as an aerobic activity.

In general, aerobic activity refers to any activity below the anaerobic threshold--usually the less vigorous the activity, the more aerobic. When Cooper first published his book Aerobics, his push was for improving general fitness by regular activity below the anaerobic threshold, in contrast to the prevailing climate on training which was focused on short bursts of high strength training.

If I might comment further, one of the other sidebars in the article you initially referenced also claimed benefits to mental function from tai chi and other milder forms of exercise, in apparent contradiction to your first posting. As some of the group of related articles you mentioned commented that corrections had been made for other factors such as BMI, age, education, etc., I worry about how well the statistics have been done in various of these studies--it is all too easy to get things seriously wrong by treating correlated factors as if they were uncorrelated.

In any case, since I exercise quite a bit for someone in my age range and would prefer to retain as much cognitive function as possible going on into the future, I like the conclusions being drawn about the positive effects of exercise for brain function, even if I have less than perfect trust in the methodology of the studies!