News :
Walk slowly for weight loss if you are obese
MEDICAL NEWS TODAY, June 16 2005 --
Leisurely walking for distance combined with low-impact cardiovascular
activity appears to be the best formula for obese people seeking to
get into shape and stay healthy, according to a University of Colorado
at Boulder study.
Ray Browning, a doctoral student in CU-Boulder's integrative
physiology department and lead author on the new study, said the results
show that people who walk a mile at a leisurely pace burn more calories
than if they walk a mile at their normal pace. In addition, those who
walk at 2 miles per hour rather than 3 miles per hour reduce the loads
on their knee joints by up to 25 percent.
"The message is that by walking more slowly, obese
individuals can burn more calories per mile and may reduce the risk
of arthritis or joint injury," he said.
Browning and his CU colleagues also found the number of
calories burned per pound of body weight is similar for obese adults
as normal sized adults walking at the same speed. Because obese people
generally have heavier legs, wider stances and swing their legs in a
wider arc, the researchers expected the cost of walking for obese people
to be significantly higher.
"This was a surprise," said Browning. "The
subjects probably are unwittingly altering their posture and walking
with straighter legs, conserving calories in the process."
A paper by Browning, CU-Boulder integrative physiology
Associate Professor Rodger Kram and undergraduates Emily Baker and Jessica
Herron was presented at the June 2005 meeting of the American College
of Sports Medicine meeting in Nashville and published recently in the
journal, "Obesity Research."
The CU-Boulder researchers based their expectations that
obese adults would have a greater energy cost when walking on previous
studies by Kram's lab team. In one study, energy expenditure increased
by about 25 percent when normal-weight people walked with a deliberately
wider stance, said Browning.
Other CU studies conducted in CU's Locomotion Laboratory
have shown that normal weight people wearing "winged" shoes
designed to force them to increase their lateral leg swing increased
the metabolic cost of walking by 30 percent, Browning said.
"As people become gradually obese, they also seem
to become particularly graceful," said Kram. "There appears
to be some sort of a physiological drive for them to minimize the amount
of energy they expend."
The researchers tested 20 men and 20 women on treadmills
and sidewalks, half of whom were of normal weight and half classified
as class 2 obese, meaning they have a body mass index, or BMI, of 30
to 40. A 5-foot 4-inch tall woman with a BMI of 30 weighs about 175
pounds, while a 6-foot man with a BMI of 30 weighs about 225 pounds.
The researchers measured each subject's body composition
using an instrument known as a DEXA scanner to measure fat mass, lean
tissue mass and bone mineral content of the total body. They also measured
the oxygen consumption and carbon dioxide production of the test subjects
to determine the energy and calories expended while walking.
As part of the ongoing research, the research team is using
a unique treadmill that can independently measure loads placed on the
left and right feet while walking, Browning said. The treadmill helps
them measure how the biomechanical forces increase with body weight
and walking speed.
The results show that brisk walking dramatically increases
the knee joint forces, which can lead to a variety of problems including
joint injuries and arthritis, the researchers said.
"This study also pointed up the phenomenal accomplishments
of obese people," said Kram. "Our test subjects lead productive
lives, and if you weigh 300 pounds, many everyday activities are athletic
endeavors."
Walking doesn't require special clothing, stressed Browning.
"It's doing some simple things, like using the stairs rather the
elevator, parking your car further from your destination, or getting
off the bus one stop early and walking. Rather than trying to walk fast,
obese individuals can gain both caloric and biomechanical benefits from
walking at a more leisurely pace."
Because walking slowly may not significantly improve an
obese person's level of cardiovascular fitness, performing other vigorous
lower-impact activities like swimming, cycling, step routines and elliptical
training workouts also are recommended, said Browning.
Much of the research was carried out at the General Clinical
Research Center housed within CU-Boulder's Wardenburg Health Center,
which receives more than $1 million in funding annually from the National
Institutes of Health.
Contact: Ray Browning
browning@colorado.edu
303-492-0926
Rodger Kram
Rodger.kram@colorado.edu
303-492-7984
Jim Scott
303-492-3114
University of Colorado
http://www.colorado.edu
(source :
www.medicalnewstoday.com)
