Page 197 - Mind Games The Aging Brain and How to Keep it Healthy

Regain an Agile Brain • 181

exercises. Participating in this type of activity increases
heart and lung fitness, overall endurance, and flexibility—
but not strength. It also increases the amount of oxygen de-
livered to the brain.
The National Institute of Aging conducted a study using
65- to 75-year-olds. After beginning aerobic workouts and
maintaining them for approximately three months, a 25 per-
cent improvement in decision-making tasks and responding
to visual and auditory cues was demonstrated.
In addition, engaging in regular, high levels of physical
activity counteracts the natural breakdown of the circadian
rhythm as we age. Low or medium levels of activity are
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not sufficient to counteract the effect of aging on the rest-
activity rhythm. To counteract the effects of age on your
rest-activity rhythm, you need a higher level of activity.
Perhaps you want to start a little slower than aerobics.
Don’t think that just because you don’t feel comfortable
with aerobics—yet—you can’t do anything at all. Numerous
studies of men and women of all ages show that those who
exercise live longer than those who are sedentary. One long
walk each week can take one year off your biological age. A
study of 40,000 women in Iowa revealed that just taking one
long walk a week can reduce the rate of death by 12 percent,
compared to all sedentary women. Jogging, swimming, and
other more vigorous activities increase health and reduce
the risk even more. 13
Resistance exercise, such as weight training, increases
the size and strength of your muscles but does not improve
endurance. Resistance training of 66-year-old men, training
at 80 percent of maximum level for 12 weeks, increased
strength approximately 5 percent each day. You don’t even
have to be in good physical shape to start.
A progressive resistance training program that lasted
eight weeks and met three times each week was designed for
institutionalized, invalid elders in their 90s. Weight lifting
improved their muscle strength 175 percent, while the cross-
sectional area of muscle increased 15 percent, and their walk-
ing speed increased by 50 percent. Some even began to walk