A growing body of research shows that working out with weights has
health benefits beyond simply bulking up one's muscles and strengthening
bones. Studies are finding that more lean muscle mass may allow kidney
dialysis patients to live longer, give older people better cognitive
function, reduce depression, boost good cholesterol, lessen the swelling
and discomfort of lymphedema after breast cancer and help lower the
risk of diabetes.
"Muscle is our largest metabolically active
organ, and that's the backdrop that people usually forget," said Kent
Adams, director of the exercise physiology lab at Cal State Monterey
Bay. Strengthening the muscles "has a ripple effect throughout the body
on things like metabolic syndrome and obesity."
Historically,
strength training was limited to athletes, but in the last 20 years, its
popularity has spread to the general public, said Jeffrey Potteiger, an
exercise physiologist at Grand Valley State University in Grand Rapids,
Mich., and a fellow of the American College of Sports Medicine. "One
can argue that if you don't do some resistance training through your
lifespan, you're missing out on some benefits, especially as you get
older or battle weight gain," he said.
When we hit middle age, muscle mass gradually diminishes by up to about
1% a year in a process called sarcopenia. Women also are in danger of
losing bone mass as they age, especially after the onset of menopause.
Some studies have shown that moderate to intense strength training not
only builds skeletal muscle but increases bone density as well.
Strength training often takes a back seat to cardiovascular training,
but it can benefit the heart in ways that its more popular cousin can't.
During cardio exercise, the heart loads up with blood and pumps it out
to the rest of the body: As a result, Potteiger said, "the heart gets
better and more efficient at pumping."
But during resistance
training, muscles generate more force than they do during endurance
exercises, and the heart is no exception, Potteiger said. During a
strength workout, the heart's muscle tissue contracts forcefully to push
the blood out. Like all muscles, stress causes small tears in the
muscle fibers. When the body repairs those tears, muscles grow. The
result is a stronger heart, not just one that's more efficient at
pumping.
Another big advantage of working out with weights is
improving glucose metabolism, which can reduce the risk of diabetes.
Strength training boosts the number of proteins that take glucose out of
the blood and transport it into the skeletal muscle, giving the muscles
more energy and lowering overall blood-glucose levels.
"If you
have uncontrolled glucose levels," Potteiger said, "that can lead to
kidney damage, damage to the circulatory system and loss of eyesight."
The benefits don't end there. A 2010 study in the Clinical Journal of
the American Society of Nephrology suggested that people on dialysis can
benefit from building muscle. Researchers found that kidney dialysis
patients who had the most lean muscle mass — a measurement derived from
the circumference of the mid-arm muscle — were 37% less likely to die
than the patients who had the least.
"This is something that has
an impact on survival," said Dr. Kamyar Kalantar-Zadeh, a principal
researcher at the Los Angeles Biomedical Research Institute and coauthor
of the study. "It's not just about having more muscle and looking
better — we're talking about life and death."
Even people who
already have chronic kidney disease could benefit from strength
workouts. Germany began to incorporate modified exercise equipment into
dialysis treatment centers in 1995, and a 2004 study in the American
Journal of Kidney Diseases examining that policy found that exercise may
improve the efficiency of dialysis by increasing blood flow through the
muscle and improving phosphate removal.
The brain may get a
boost from the body's extra muscle as well. A 2010 study in Archives of
Internal Medicine found that women ages 65 to 75 who did resistance
training sessions once or twice a week over the course of a year
improved their cognitive performance, while those who focused on balance
and tone training declined slightly. One reason for the improvement,
researchers believe, may be that strength training triggers the
production of a protein beneficial for brain growth.
This study was triggered by another that looked at resistance
training as a way to reduce the risk of falls in older people, said
coauthor Teresa Liu-Ambrose, a researcher at the University of British
Columbia's Centre for Hip Health and Mobility in Vancouver. As the study
progressed, she said she noticed that participants "were able to take
on new tasks, like taking the bus by themselves. They were able to
prepare and plan for things and execute them."
Strength training
could be easier for people with mobility problems who might find it
easier to navigate a stationary weight than a moving treadmill.
"It's never too late to start," Adams said. "The benefits are great."
Source; latimes.com
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