You may have read reports that suggest weight training and other exercise can sustain or improve brain function as we age. Now, a new randomized study has shown that seniors can improve thinking and executive skills after an organized strength-training program. (In a randomized program, the allocation of subjects to each study group is a random process.)
Dementia is the medical term for the decline in brain function as we age. Alzheimer's disease is a major disease of the various forms of dementia.
In this small study, seniors in one group were given a weight-training program, another group an aerobic training program, and a third group a balance and stretching program. Here's how it worked out.
Weight Training and Dementia
Investigators studied 86 senior women aged 70-80 years old with probable mild brain (cognitive) impairment for six months, and split them into three groups. Each group underwent either weights, aerobic, or balance training twice a week, and then underwent cognitive tests. Brain function was assessed using magnetic resonance imaging (MRI).
Compared to the balance group, which was used as a control, weight training "significantly improved" cognitive brain function performance. Aerobic training was not associated with the same level of improvement.
The study showed improvement in two thinking abilities that are sensitive to the effects of aging and show up in early dementia syndromes -- executive function and associative memory. Declines in these areas can occur in the early stages of Alzheimer's disease.
Associative memory is the ability of one thought to flow on to another "associated" thought -- for example, "fire means hot." Executive function refers to the extensive "command and control" abilities of the brain in everyday life, from decision-making to personal interactions.
The researchers did not suggest that early dementia could always be reversed, only that strength training might slow or arrest it. Two weight-training sessions weekly with a variety of exercises were required to produce the advantageous results.
Summary and Discussion
In another recent study of total daily exercise, seniors who exercised the most had half the incidence of Alzheimer's disease than those who did the least exercise. So, with reference to the above study, doing your aerobic exercise could still be valuable in the overall context of protection from dementia over the long term.
In addition, the intensity of the exercise prescription may be important. Some evidence exists that higher intensities of aerobic exercise in the region of 75-85% of maximum heart rate might produce better outcomes in alleviating or preventing dementia. Lifting weights can initiate such intensities, even if only for short periods of time.
The bottom line in interpreting these studies is that an ideal program to stave off dementia is likely to be a regular exercise program that includes resistance training, moderate aerobic exercise, and perhaps some higher-intensity aerobic exercise as well.
Arch Intern Med. 2012 Apr 23;172(8):666-8. Resistance training promotes cognitive and functional brain plasticity in seniors with probable mild cognitive impairment. Nagamatsu LS, Handy TC, Hsu CL, Voss M, Liu-Ambrose T.
Arch Intern Med. 2010 Dec 13;170(22):2036-8. Sustained cognitive and economic benefits of resistance training among community-dwelling senior women: a 1-year follow-up study of the Brain Power study. Davis JC, Marra CA, Beattie BL, Robertson MC, Najafzadeh M, Graf P, Nagamatsu LS, Liu-Ambrose T.
Arch Intern Med. 2010 Jan 25;170(2):170-8. Resistance training and executive functions: a 12-month randomized controlled trial. Liu-Ambrose T, Nagamatsu LS, Graf P, Beattie BL, Ashe MC, Handy TC.
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