Longevity
and Aging
Exercise, even after age 50,
can add healthy and active years to one's life. Studies continue to show
that it is never too late to start exercising and that even small
improvements in physical fitness can significantly lower the risk of
death. Simply walking regularly can prolong life in the elderly.
Moderately fit people, even if they smoke or have high blood pressure,
have a lower mortality rate than the least fit. Resistance training is
important for the elderly, because it is the only form of exercise that
can slow and even reverse the decline in muscle mass, bone density, and
strength. Adding workouts that focus on speed and agility may be even
more protective for older people. Flexibility exercises help reduce the
stiffness and loss of balance that accompanies aging.
Diabetes
Diabetes, particularly type 2,
is reaching epidemic proportions throughout the world as more and more
cultures adopt Western dietary habits. Aerobic exercise is proving to
have significant and particular benefits for people with both type 1 and
type 2 diabetes; it increases sensitivity to insulin, lowers blood
pressure, improves cholesterol levels, and decreases body fat. Regular
exercise, even of moderate intensity, improves insulin sensitivity. In
fact, studies of older people who engage in regular, moderate, aerobic
exercise (e.g., brisk walking, biking) lower their risk for diabetes
even if they don't lose weight. Anyone on insulin or who has
complications from diabetes must take special precautions before
embarking on a workout program (see, What Are the Hazards of
Exercise?, below).
Effects on Bones and Joints
Osteoarthritis.
Exercise helps to reduce pain and stiffness, and increases flexibility,
muscle strength, endurance, and well being. Exercising also helps people
reduce their weight and maintain weight loss. Osteoarthritis patients
should avoid high-impact sports such as jogging, tennis, and
racquetball. The three types of exercise that are best for people with
arthritis are range of motion, strengthening (or resistance), and
aerobic exercises. Strengthening exercises include isometric exercises
(pushing or pulling against static resistance) and stretching exercises
to build strength and flexibility without unduly stressing the joints.
These exercises may be particularly important if leg muscle weakness
turns out to be a cause of osteoarthritis, as some research suggests.
Low-impact aerobics also help stabilize and support the joints and may
even reduce inflammation in some joints. Cycling and walking are
beneficial, and swimming or exercising in water is highly recommended
for people with arthritis. One study compared a group of patients who
embarked on an aerobic and resistance exercise program with a group that
received patient education; the exercising group developed less
disability and pain and showed a better ability to perform physical
tasks. Patients should strive for short but frequent exercise sessions
guided by physical therapists or certified instructors.
Osteoporosis.
Exercise is very important for slowing
the progression of osteoporosis. Women should begin exercising before
adolescence, since bone mass increases during puberty and reaches its
peak between ages 20 and 30. Weight bearing exercise, which applies
tension to muscle and bone, encourages the body to compensate for the
added stress by increasing bone density by as much as 2% to 8% a year.
High-impact weight-bearing exercises, such as step aerobics, are very
protective for premenopausal women. These exercises, however, increase
the risk for osteoporotic fractures in elderly patients, who would
benefit most from regular, brisk, long walks. Even moderate exercise (as
little as an hour a week) helps reduce the risk for fracture, but
everyone who is in good health should aim for more. Careful weight
training is beneficial as well for older women. Low-impact exercises
that improve balance and strength, particularly yoga and T'ai Chi, have
been found to decrease the risk of falling; in one study, T'ai Chi
reduced the risk by almost half.
Back Problems.
One of the most common complaints of
modern men and women, lower-back pain, afflicts up to 80% of all
Americans. Sedentary living, obesity, poor posture, badly designed
furniture, and stress all contribute to back pain. An appropriate
exercise program focusing on flexibility and strengthening the muscles
in the abdomen may help prevent back problems. Yoga stretching is
beneficial and can be incorporated into the warm-up and cool-down
periods. The best exercises for athletes with bad backs include
swimming, walking, and cross-country skiing. High-impact sports,
including aerobic dance and downhill skiing, should be avoided.
Exercises that strengthen the abdominal muscles such as partial sit-ups,
which maintain the back's normal curve and help support the body's
weight, can alleviate stress on the lower back. However, the classic
full sit-up (raising your head and shoulders off the floor up to your
knees) may aggravate back pain and should be avoided by anyone at risk
for lower back problems.
Lung Disease
Although exercise does not
improve lung function, training helps some patients with chronic lung
disease by strengthening their limb muscles, thus improving endurance
and reducing breathlessness.
Cancer
A number of studies have
indicated that regular, even moderate, exercise reduces the risk of
colon cancer. Strenuous activity, in fact, adds only slight or no
additional benefit. Moderate exercise may also help reduce the risk for
prostate cancer and possibly for breast cancer. A recent study of
100,000 nurses, however, suggested that the benefits of exercise on
breast health may be greater or lesser at different times in a woman's
life, depending on her menstrual status and estrogen levels. For
example, the study found no added protection against from exercise in
young adulthood (when the disease is uncommon in any case).
Effects on Colds and Flu
Although offering no evidence
of improved immunity from exercise, one study reported that people who
exercised as little as once a week in employee fitness programs averaged
nearly five fewer sick days annually than those who did not participate
in such programs. The immediate effect of exercise on the immune system
is uncertain. High-intensity or endurance exercises might actually
suppress the immune system while they are performed. Some highly trained
athletes, for instance, report being susceptible to colds after
strenuous events. A recent study suggested that in people who already
have colds, exercise has no effect on the illness -- severity or
duration of the infection. People should avoid strenuous physical
activity when they have high fevers or widespread viral illnesses,
however.
Central Nervous System Diseases
People with multiple sclerosis,
Parkinson's disease, and Alzheimer's disease should be encouraged to
exercise. Specialized exercise programs that improve mobility are
particularly valuable for Parkinson's patients. Patients with
neurological disorders who exercise experience less spasticity as well
as reduction in -- and even reversal of -- muscle atrophy. In addition,
the psychological benefits of exercise are extremely important in
managing these disorders. Exercise machines, aquatic exercises, and
walking are particularly useful.
Pregnancy
Healthy women with normal
pregnancies should exercise at least three times a week, being careful
to warm up, cool down, and drink plenty of liquids. Many prenatal
calisthenics programs are available. Experts advise, in general, that
when exercising, the expectant mother's pulse rate should not exceed 70%
to 75% of the maximum heart rate or more than 150 beats per minute. Fit
women who have exercised regularly before pregnancy, however, may work
out more intensively as long as no discomfort occurs. According to a new
study, vigorous exercise may improve the chances for a timely delivery.
Overly strenuous exercise during pregnancy is not advocated,
however, for women who did not exercise intensely before becoming
pregnant. And all pregnant women should avoid high-impact, jerky, and
jarring exercises, such as aerobic dancing, which can weaken the pelvic
floor muscles that support the uterus. During exercise, women should
monitor their temperature to avoid overheating -- a side effect that can
damage the fetus. (No pregnant women should use hot tubs or steam baths,
which can cause fetal damage and miscarriage.) Swimming may be the best
option for most pregnant women. It involves no impact, overheating is
unlikely, and swimming face down promotes optimum blood flow to the
uterus. Walking is also highly beneficial. To strengthen pelvic muscles,
women should perform Kegel exercises at least 6 times a day, which
involve contracting the muscles around the vagina and urethra for 3
seconds 12 to 15 times in a row.
Gastrointestinal Problems
Older people who exercise
moderately may have a lower risk for severe gastrointestinal bleeding.
Experts suggest that moderate exercise might even reduce the risk for
some intestinal disorders, including ulcers, irritable bowel syndrome,
indigestion, and diverticulosis.
Leg Cramps
Exercise can even improve pain
from clogged arteries in the legs, a condition called intermittent
claudication. The best approach in such cases is to walk until pain
develops; then rest until pain resolves before resuming walking. In
six-month studies, people had tripled the amount of time they could walk
before the onset of pain.
Weight Loss
Exercise burns calories and can
help individuals fight obesity. If caloric intake remains constant,
regular workouts lead to weight loss. Be forewarned, however, that the
pounds won't melt off magically. It takes 35 miles of walking or jogging
to consume the calories in one pound of fat. Effective weight loss means
a long-term commitment to a regular program of vigorous exercise. One
recent study indicated that for obese patients, a few daily sessions for
as short as 10 minutes each was effective in helping the patients adhere
to an exercise program. Abdominal crunches may help replace abdominal
fat with muscle. To perform this exercise, the individual lies on the
back with the head and shoulders raised; he or she contracts the stomach
muscles, curling the torso slightly forward. Abdominal fat is a
particular danger to the heart, although it is unknown whether doing
crunches will specifically protect against heart disease. Swimming is
less effective than walking or cycling in reducing body fat, but overall
regular aerobic exercise is a good way to shed pounds. Contrary to
popular belief, exercise does not increase appetite in people who want
to lose weight; oddly enough, however, exercise improves appetite in
people who are already lean. People should be warned that without
dieting, weight loss may be minimal with exercise alone, because dense
muscle mass replaces fat as the body gets more fit. Nonetheless, a fit
body will look more toned and be healthier.
Psychological and Emotional Benefits
Aerobic exercise is linked with
improved mental vigor, including reaction time, acuity, and math skills.
Exercising may even enhance creativity and imagination. According to one
study, older people who are physically fit respond to mental challenges
just as quickly as unfit young adults. (Stretching and weight training
appear to have no such effects.) Both aerobic and nonaerobic workouts
have been shown to reduce depression. According to one study, exercise
was as effective for improving mood in people with clinical depression
as some common forms of psychotherapy. Either brief periods of intense
training or prolonged aerobic workouts can raise levels of important
chemicals in the brain, such as endorphins, adrenaline, serotonin, and
dopamine, that produce feelings of pleasure, causing the so-called
runner's high. One study found that teenagers who were active in sports
have a much better sense of well being than their sedentary peers; the
more vigorously they exercised, the better was their emotional health.
In one study, regular brisk walking cut in half the incidence of sleep
disturbances in people who suffer from them. It should be noted that
exercise in the evening, however, can cause sleep disturbances.
Rhythmic aerobic and yoga exercises may be particularly helpful for
combating stress, anxiety, and sleeplessness.
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