What you do and when you do it affects how well you think and remember
A four-year study involving 716 elderly (average age 82) has revealed that those who were most physically active were significantly less likely to develop Alzheimer’s than those least active. The study is unique in that, in addition to self-reports of physical and social activity, activity was objectively measured (for up to 10 days) through a device worn on the wrist. This device (an actigraph) enabled everyday activity, such as cooking, washing the dishes, playing cards and even moving a wheelchair with a person's arms, to be included in the analysis.
Cognitive performance was assessed annually. Over the study period, 71 participants (10%) developed Alzheimer’s.
The study found that those in the bottom 10% of daily physical activity were more than twice as likely (2.3 times) to develop Alzheimer's disease as those in the top 10%. Those in the bottom 10% of intensity of physical activity were almost three times (2.8 times) as likely to develop Alzheimer's disease as people in the top 10%.
Moreover, the level of activity was associated with the rate of cognitive decline.
The association remained after motor function, depression, chronic health conditions, and APOE gene status were taken into account.
The findings should encourage anyone who feels that physical exercise is beyond them to nevertheless engage in milder forms of daily activity.
Another recent study, involving 331 cognitively healthy elderly, has also found that higher levels of physical activity were associated with better cognitive performance (specifically, a shorter time to complete the Trail-making test, and higher levels of verbal fluency) and less brain atrophy. Activity levels were based on the number of self-reported light and hard activities for at least 30 minutes per week. Participants were assessed in terms of MMSE score, verbal fluency, and visuospatial ability.
 Buchman, A. S., Boyle P. A., Yu L., Shah R. C., Wilson R. S., & Bennett D. A.
(2012). Total Daily Physical Activity and the Risk of AD and Cognitive Decline in Older Adults.
Neurology. 78(17), 1323 - 1329.
 Benedict, C., Brooks S. J., Kullberg J., Nordenskjöld R., Burgos J., Le Grevès M., et al.
(Submitted). Association between physical activity and brain health in older adults.
Neurobiology of Aging.
Another study has come out suggesting that the advantage of mental stimulation is to delay cognitive decline, but at the cost of faster decline later (it’s still a good bargain).
A long-running study involving 1,157 healthy older adults (65+) who were scored on a 5-point scale according to how often they participated in mental activities such as listening to the radio, watching television, reading, playing games and going to a museum, has found that this score is correlated to the rate of cognitive decline in later years.
Some 5 ½ years after this initial evaluation, 395 (34%) were found to have mild cognitive impairment and 148 (13%) to have Alzheimer’s. Participants were then tested at 3-yearly intervals for the next 6 years. The rate of cognitive decline in those without cognitive impairment was reduced by 52% for each point on the cognitive activity scale, but for those with Alzheimer's disease, the average rate of decline per year increased by 42% for each point on the cognitive activity scale. Rate of decline was unrelated to earlier cognitive activity in those with MCI (presumably they were at the balance point).
This is not terribly surprising when you think of it, if you assume that the benefit of mental stimulation is to improve your brain function so that it can better cope with the damage happening to it. But eventually it reaches the point where it can no longer compensate for that damage because it is so overwhelming.
 Wilson, R. S., Barnes L. L., Aggarwal N. T., Boyle P. A., Hebert L. E., Mendes de Leon C. F., et al.
(2010). Cognitive activity and the cognitive morbidity of Alzheimer disease.
Neurology. 75(11), 990 - 996.
More data from the National Survey of Midlife Development in the United States has revealed that cognitive abilities reflect to a greater extent how old you feel, not how old you actually are.
More data from the National Survey of Midlife Development in the United States has revealed that cognitive abilities reflect to a greater extent how old you feel, not how old you actually are. Of course that may be because cognitive ability contributes to a person’s wellness and energy. But it also may reflect benefits of trying to maintain a sense of youthfulness by keeping up with new trends and activities that feel invigorating.
 Schafer, M. H., & Shippee T. P.
(2009). Age Identity, Gender, and Perceptions of Decline: Does Feeling Older Lead to Pessimistic Dispositions About Cognitive Aging?.
The Journals of Gerontology Series B: Psychological Sciences and Social Sciences. 65B(1), 91 - 96.
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