More Exercise, Less Calories Delays Aging by
Repairing Link Between Nerve Cells, Muscles
Finding in lab mice may illuminate a reason for the
beneficial effects of these regimens on aging
Professors Josh
Sanes and Jeff Lichtman say that their study in mice shows that
some of the debilitation of aging is caused by the deterioration
of connections that nerves make with the muscles they control,
structures called neuromuscular junctions. Photo by Rose
Lincoln/Harvard Staff Photographer
Aug. 2, 2010 Earlier studies have established
that exercise plus restricting calorie intake helps delay the mental and
physical deterioration caused by aging. Harvard researchers think they
may know how. They have uncovered a mechanism through which caloric
restriction and exercise delay aging by rejuvenating connections between
nerves and the muscles that they control.
The research described this week in the journal
Proceedings of the National Academy of Sciences, begins to explain
how exercise and restricted-calorie diets help to stave off the mental
and physical degeneration of aging.
"Caloric restriction and exercise have numerous,
dramatic effects on our mental acuity and motor ability," says Joshua
Sanes, a professor of molecular and cellular biology and director of the
Center for Brain Science at Harvard University.
During 20-year study, half the animals permitted to
eat freely have survived, while 80% given the same diet, but with 30%
fewer calories are still alive
"This research gives us a hint that the way these
extremely powerful lifestyle factors act is by attenuating or reversing
the decline in our synapses."
The study was conducted in the labs of and Sanes
and Jeff Lichtman.
Sanes says their research, conducted with mice
genetically engineered so their nerve cells glow in fluorescent colors,
shows some of the debilitation of aging is caused by deterioration of
connections that nerves make with the muscles they control, structures
called neuromuscular junctions.
These microscopic links are remarkably similar to
the synapses (junction between nerve cells, where the club-shaped tip of
a nerve fiber almost touches another cell in order to transmit signals)
that connect neurons to form information-processing circuits in the
brain.
In a healthy neuromuscular synapse, nerve endings
and their receptors on muscle fibers are almost a perfect match, like
two hands placed together, finger to finger, palm to palm. This lineup
ensures maximum efficiency in transmitting the nerve's signal from the
brain to the muscle, which is what makes it contract during movement.
As people age, however, the neuromuscular synapses
can deteriorate in several ways.
Nerves can shrink, failing to cover the muscle's
receptors completely. The resulting interference with transmission of
nerve impulses to the muscles can result in wasting and eventually even
death of muscle fibers. This muscle wasting, called sarcopenia, is a
common and significant clinical problem in the elderly.
The new work shows that mice on a
restricted-calorie diet largely avoid that age-related deterioration of
their neuromuscular junctions (synapses), while those on a one-month
exercise regimen when already elderly partially reverse the damage.
"With calorie restriction, we saw reversal of all
aspects of the synapse disassembly. With exercise, we saw a reversal of
most, but not all," Sanes says.
Because of the study's structure - mice were on
calorie-restricted diets for their whole lives, while those that
exercised did so for just a month late in life - Sanes cautions against
drawing conclusions about the effectiveness of exercise versus calorie
restriction.
He notes that longer periods of exercise might have
more profound effects, a possibility he and Lichtman are now testing.
Though much of Sanes and Lichtman's work focuses on
brain synapses, both have investigated neuromuscular synapses for many
years. Neuromuscular junctions are large enough to be viewed by light
microscopy, and can be a jumping-off point for brain study, highlighting
areas of inquiry and potential techniques.
"These findings in neuromuscular synapses make us
curious to know whether similar effects might occur in brain synapses,"
Sanes says.
While the changes to the synapses through caloric
restriction and exercise were clear in the images the researchers
obtained, Sanes cautioned that their work was structural, not
functional, and they have not yet tested how well the synapses worked.
The research, largely conducted by postdoctoral
researchers Gregorio Valdez, Juan Tapia, and Hyuno Kang at Harvard
University, was funded by the National Institute on Aging, National
Institute of Neurological Disorders and Stroke, and Ellison Medical
Foundation.
Study important because it suggests that resveratrol
and caloric restriction may govern the same master genetic pathways
related to aging -
June 4, 2008
Diet and exercise prevent of age-related disease,
but reducing calories needed to slow aging
May 31, 2006 If you prefer dieting to exercise,
you may be in luck, assuming you, like most senior citizens, are seeking
ways to live longer. A new study found that only calorie restriction
not exercise increases the maximum lifespan up to 50 percent.
Read more...
Study shows it can
even reverse aging cell and organ damage
May 8, 2006 - A lifelong habit of trimming just a
few calories from the daily diet can do more than slim the waistline - a
new study shows it may help lessen the effects of aging. Scientists from
the University of Florida's Institute on Aging have found that eating a
little less food and exercising a little more over a lifespan can reduce
or even reverse aging-related cell and organ damage in rats.
Read more...
Many elderly people feel that it is too late for
them to improve their health, but that is simply not true.
Dec. 14, 2007 The author of a new study of
scientific data about senior citizens claims he has an important message
for the elderly: It's not too late to improve your health through diet
and exercise, even if you've had an unhealthy lifestyle in the past!
Read more...
Rats on restricted calorie diet had
significantly higher physical performance
Oct.
31, 2007 Although research has well established that a healthy diet is
very beneficial to longevity, scientist say in a new study they have
proven for the first time that severely restricting calories not only
leads to a longer life, it also maintains physical fitness into advanced
age.
Read
more...
Senior citizens increasingly turn to exercise,
healthy diet as keys to rejuvenation
January 16, 2007 Senior citizens are increasingly
turning to exercise and healthier diets in an attempt to regain the vim
and vigor of younger years. Many fail in this quest due to frustration,
which may be due to misconceptions and bad information that floats
around gyms, the Internet and even senior centers.
Read more...
Results are from research that is part of NIH-funded
longevity study
November 8, 2006 You are getting older. You see
many of your friends suffering with diabetes. You know it is one of the
leading causes of premature death. What is the best way to avoid it
exercise of diet?
Read more...
24 studies find effective weight-loss
needs
exercise and diet
By Taunya English, Science Writer, Health Behavior
News Service
October 27, 2006 - If youre overweight and hoping
to shed pounds, but still regularly indulging in french fries dont
count on exercise to salvage your weight-loss efforts.
Stress reduction and diet also cited as helping
memory
Dec. 12, 2005 - To truly slim
down, obese and overweight people need to watch what they eat and get
moving, according to a new analysis of weight-loss trials dating back to
1985.
Read more...
May 25, 2005 New research says late Boomers and
Senior Citizens those 55 to 75 - can sustain and maybe improve bone
mass with a moderate exercise program. The researchers say their results
debunk the myth that exercising to lose excess body fat, unlike
dieting alone, comes at a cost to bone health. Read more...
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