To Explain Why People Don't Work Out, Scientists Look to Chemistry, Biology
Wall Street Journal
February 19, 2013
By SHIRLEY S. WANG
When
it comes to exercise, many people seem to fall into two distinct camps:
those who love a vigorous, sweat-soaked workout and those who view it
as a form
of torment.
Scientists
have discovered that reasons for people not wanting to work out and go
to the gym isn't just laziness. It is rooted in the body's chemistry.
WSJ's
Shirley Wang has details on the News Hub. Photo: Getty Images.
With
hopes of getting more people up and moving, scientists are looking at
the body's biological and chemical processes for clues to understanding
what's behind
differing attitudes toward exercise. That could mean there are factors
beyond motivation and discipline to explain why some people enjoy
exercising and others don't.
Sources: Panteleimon Ekkekakis, Iowa State University
One
finding so far: How people interpret their body's sensations during and
after exercise plays a large role in whether they enjoy it. Also,
researchers at
Iowa State University found that people's physical capacity could be
much lower than many realize, so many people push beyond their limits
without realizing it. For example, for sedentary people, just cooking
dinner could count as exercise and they need to
build up to even walking, the researchers found.
Dan
Cederholm has tried for years to find some type of exercise he could
stick with. He finds the gym boring and basketball and baseball leagues
unappealing.
As for running? "My shins always hurt like hell," says Mr. Cederholm,
38, a Web designer from Salem, Mass.
His
friend Rick Johnson, on the other hand, competes in 20 road races a
year. He remembers that even as a kid, when he was told to run a lap
during gym class,
he would ask to do extras. "To me, it seems very foreign to say I don't
enjoy sweating or running," says Mr. Johnson, 41, an editor who also
lives in Salem.
From
couch potatoes to Olympic athletes, everyone has a physical capacity
for exertion, beyond which the body becomes stressed and begins to feel
bad. How
much stems from genetic factors—things like lung capacity, oxygen
transport and the rate at which oxygen is used in the muscle cells—is
still a subject of scholarly debate. Estimates vary from 10% to 50%,
says Panteleimon Ekkekakis, a professor of kinesiology
at Iowa State who has been studying the psychophysiology of exercise.
But
many sedentary people push beyond their intrinsic range when they try
to exercise too quickly or intensely, which can make them hate the
activity and want
to stop, says Dr. Ekkekakis.
The
idea hinges on something called the "ventilatory threshold." Normally
when people breathe, they expel an amount of carbon dioxide that is
equal to the
amount of oxygen taken in. But beyond the ventilatory threshold, the
release of carbon dioxide begins to exceed the body's intake of oxygen.
This excess release of carbon dioxide is a sign that the muscles have
become more acidic, which the body finds stressful.
For
most individuals, the ventilatory threshold is around 50% to 60% of the
way to their maximum capacity, though there is tremendous individual
variation.
For elite athletes, the threshold may be as high as 80%, while sedentary
people may hit it at 35%.
By
using tricks such as listening to music, people can continue to feel
good even slightly past their ventilatory threshold, Dr. Ekkekakis and
his colleagues
have found. As people approach their maximum capacity, however, the
feel-bad reaction is unavoidable.
And
while both ventilatory threshold and maximum capacity can be slowly
increased, people have to have enough positive experiences to stick with
exercise over
time so they actually can boost these limits.
In
continuing studies of obese, sedentary but otherwise healthy
middle-aged women, Dr. Ekkekakis found that some individuals reach their
ventilatory threshold
after just one minute at a slow pace on a treadmill. Some women's
thresholds are so low that they would reach their maximum capacity
simply by doing the dishes or cooking, says Dr. Ekkekakis.
This
means that though many weight-loss interventions suggest walking as the
primary form of physical activity, it is probably too hard for many
people.
How
people interpret some of the physical sensations of exertion or
fatigue, such as buildup of lactic acid in muscle or increases in body
temperature, can
also influence whether they stick with an exercise routine. Some people
tend to read such physical cues as a sign of a good workout or progress,
whereas many sedentary people just find them uncomfortable or painful,
say researchers.
Elite
athletes have even been dubbed "benign masochists" because they appear
to enjoy the pain of exertion, says Dominic Micklewright, a researcher
and curriculum
director at the Centre for Sports & Exercise Science at the
University of Essex in the U.K.
The
sensation of how hard one is working also can be influenced by some
surprising external factors. In one study published in the journal
Environmental Science
and Technology last year, Dr. Micklewright and his team examined how the
color of the imagery participants viewed while cycling would affect
their mood and perceived feelings of exertion. After viewing scenes that
involved green trees, participants reported
feeling happier and their exercise less difficult than when the same
scenes appeared in black-and-white or red, suggesting that exercising in
nature or simulated green spaces could be helpful for exercisers, says
Dr. Micklewright.
Jason Henry for The Wall Street Journal
It wasn't until age 48 that Sharon Weinbar (in black) of Hillsborough, Calif., found a workout she looked forward to: rowing.
Researchers
have found several other psychological factors and cognitive tricks
that can help boost the motivation to move. Three that appear critical
include
how competent a person feels, whether he or she feels they have some
control or choice in the matter and, for many, whether the activity
fosters social relatedness, says Sarah Ullrich-French, a professor in
kinesiology at Washington State University in Pullman,
Wash.
Adults
can be discouraged from exercising by not knowing what to do or how to
do it. Those who were athletic in childhood may be frustrated by how
their abilities
have deteriorated over time. Dr. Ullrich-French suggests that adults try
new activities where they won't be comparing themselves.
For
Mr. Cederholm, the Web designer from Salem, going back to hockey, which
he had enjoyed as a boy, wasn't an option. But the first time he played
squash
was an epiphany. "It was fun at the level that you don't even realize
you're sweating your butt off," says Mr. Cederholm, who now plays three
to four hours a week with a friend or practices shots by himself on the
court.
Sharon
Wienbar, a venture capitalist in Hillsborough, Calif., became a rower
at the age of 48 because she enjoys the feeling of speeding along on the
water,
discussing her workout routines with her teammates and having a coach
who helps her get better. "A couple months into rowing, it was like a
light switch going on in my head," she says.
Once
a "geeky, bookish" child who was always picked last for gym, Ms.
Wienbar says rowing is now part of her identity and has prompted her to
think of herself
as an athlete.
And
at age 51, she says she enjoys the physical feeling of pushing herself.
"I don't even feel like I've reached the maximum," says Ms. Wienbar.
"I'm in better
shape now than I was 10 years ago. Maybe I'll be in even better shape in
a decade."
Write to Shirley S. Wang at shirley.wang@wsj.com
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