muscle loss with aging / health benefits of intense exercising - per dr gabe mirkin
Dr. Gabe Mirkin's Fitness and Health E-Zine
November 13, 2011
www.drmirkin.com
Sarcopenia: Muscle Loss with Aging
Competitive masters athletes, 40 to 81 years old, who
trained four to five times per week did not lose any muscle size
or significant strength with aging (The Physician and
Sportsmedicine, October 2011;39(3):172-8). This shows that loss
of muscle size and strength in older people is caused by lack of
exercise, not just with aging. The athletes did gain fat in spite
of exercising. Those in their 70s had almost as much strength and
thigh muscle size as those in their 40s.
MOST PEOPLE LOSE MUSCLE: Recent studies show that after age
40, men lose more than eight percent of their muscle size each
decade, and this loss of muscle increases after age 70. The
people who lose the most muscle are usually the ones who die
earliest. They are also most at risk for falls and broken bones.
HOW EXERCISE PREVENTS MUSCLE LOSS WITH AGING: Muscles are
made up of thousands of individual muscle fibers. Each muscle
fiber is innervated by a single nerve. With aging, humans lose
the nerves that innervate muscle fibers, and with each nerve loss,
they lose the associated muscle fiber so muscles become smaller.
We used to think this happens because of aging. However, this
new study and others show that lifelong competitive athletes do not
lose the nerves that innervate their muscles with aging. They retain
the nerves and therefore retain most of the muscle fibers
that they would have lost if they were inactive.
MESSAGE: If you exercise regularly, continue to do so. If
you don't, check with your doctor and then get instructions on how
to start an exercise program.
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Intense Exercise Gives More Health Benefits than Just Exercising
Intense exercise is even more effective than just
exercising in prolonging life and preventing disease. A study
from Norway shows that the more fit you are, the fewer heart
attack risk factors you have and the less likely you are to
develop diabetes (Medicine & Science in Sports & Exercise, August,
2011;43 (8):1465).
VO2 PEAK: The authors measured level of fitness by a test
called VO2 peak: the highest amount of oxygen a person can use in
an all-out exercise test. It is a direct measure of a person's
fitness, and the more intensely a person exercises, the greater
the increase in VO2 peak. Intensity of exercise is far more important
than duration in determining peak oxygen uptake.
Women whose fitness values were low (VO2 peak <35.1 mL kg-
1 min-1) were five times more likely to have heart attack risk
factors compared to those whose fitness was high (VO2 peak (40.8 mL kg-1
min-1). Men with low fitness (<44.2 mL kg-1 min-1) were eight
times more likely to have heart attack risk factors than those
with high fitness ((50.5 mL kg- 1 min-1).
Furthermore, those who changed from low to high intensity
training had substantially higher VO2 peak at follow-up compared
with people whose activity remained low.
HEART ATTACK RISK FACTORS: Heart attack risk factors
include high blood pressure; high blood levels of total
cholesterol, triglycerides, the bad LDL cholesterol, blood sugar,
and the diabetes test HBA1C; low levels of the good HDL
cholesterol or vitamin D3; being overweight, especially if you
store fat primarily in your belly; and not exercising.
STRESS AND RECOVER: Competitive athletes know that running,
cycling or skiing lots of slow miles will not help them in
competition. They call these "junk miles" and exercise at a slower
pace only on the day or days after a very intense workout when
their muscles feel sore and they are recovering from exercising
almost as intensely as they could. The same type of "stress and
recover" training that makes a competitive athlete faster and
stronger, can make you healthier, prevent disease and prolong your
life.
Realize that every time you exercise intensely, your
muscles are damaged and feel sore on the next day. If you try to
exercise intensely when your muscles feel sore, you increase your
risk for an injury. Plan to exercise at low intensity on the day
after you exercise intensely. Most athletes set up their programs
so that they go intensely three times a week (for example,
Tuesdays, Thursdays, and Saturdays) and go slowly on the other
four days. If they feel sore on a scheduled intense day, they
usually go easy instead or take the day off. Exercisers probably
should go easy on the day after an intense workout, regardless of
how well they feel.
CAUTION: Every healthy person should exercise the way
competitive athletes train. The greatest concern is that many
North Americans have blocked arteries leading to their hearts and
do not know it. These people could die of heart attacks if they
exercise intensely. Intense exercise forces the heart to consume
huge amounts of oxygen. If the heart cannot receive the amount of
oxygen it needs, it can start to beat irregularly and the person
can die. Unfortunately, the best test to check for blocked
arteries is an extremely expensive Stress Thallium Test and most
people will never receive that test.</pre>
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