Fw: News release from UT Southwestern

[Guest guest]

----- Original Message -----

From: " Robin Amerine " <Robin.Amerine@...>

<utswnews@...>

Sent: Monday, September 17, 2001 4:17 PM

Subject: News release from UT Southwestern

Media Contact: Amy Shields

214-648-3404

amy.shields@...

SIX MONTHS OF EXERCISE REVERSES DECLINE IN PHYSICAL CONDITIONING ASSOCIATED

WITH AGING, UT SOUTHWESTERN RESEARCHERS REPORT

DALLAS - Sept. 18, 2001 - Six months of exercise can reverse the decline in

physical conditioning associated with aging, researchers at UT Southwestern

Medical Center at Dallas reported in a 30-year follow-up to the 1966

landmark Dallas Bed Rest and Training Study.

The researchers also report that three weeks of bed-rest deconditioning has

a more profound impact on physical work capacity than 30 years of aging.

Their findings are based on test results of the five healthy men, ages 50 to

51, who were originally studied in 1966 and volunteered to participate in

the 30-year follow-up, which began in 1996. The study represents one of the

longest longitudinal evaluations of a group's response to exercise and

provides novel findings regarding the effects of two endurance training

programs separated by a 30-year period.

The 1966 study, considered one of the most pivotal studies in exercise

science, evaluated the response to endurance exercise training after a

20-day period of bed rest. The two-part, follow-up study, which is reported

in today's issue of Circulation: Journal of the American Heart Association,

evaluates the effect of age on cardiovascular response to exercise testing,

and the effect of age on cardiovascular adaptation to endurance exercise

training.

" This pair of studies together underscore the relationship between physical

activity and cardiovascular fitness, or aerobic power, " said Dr. Darren

McGuire, assistant professor of internal medicine and lead author of the

study.

" First, 20 days of bed rest - which is the ultimate 'sedentary' state - in

these subjects when they were 20 years old had a more profound negative

impact on their cardiovascular fitness than did 30 years of aging, " McGuire

said.

" Second, an endurance training program using a relatively modest intensity

of training was able to reverse 100 percent of the loss of cardiovascular

capacity, returning the group to their 1966 baseline levels of aerobic

power. "

The five study volunteers completed a six-month, individualized endurance

training program. Two study participants took part in walking exercises, two

jogged and the fifth trained on a stationary bicycle. The endurance training

was increased weekly.

" By the end of the study, the subjects were exercising weekly about 4 ½

hours divided into four to five exercise sessions, " McGuire said.

Notable changes in the five participants from 1966 to 1996 included weight

gain, and a more than doubling in body fat.

Only two of the five volunteers were following a regular exercise regimen

prior to the follow-up study. The remaining three had not performed regular

exercise in six months to 20 years before the present study.

" This study clearly provides evidence that even an older person who has

failed to maintain fitness over time can benefit from an exercise program, "

said Dr. Levine, associate professor of internal medicine and

director of the Institute for Exercise and Environmental Medicine, a joint

venture between UT Southwestern and Presbyterian Hospital of Dallas.

" Starting an exercise program when you are older is still useful and can

combat the effects of aging, " said Levine, who is also a study

co-investigator.

" Moreover, if you stop exercise you can lose what you have gained relatively

quickly. Therefore, exercise must be a lifelong health habit - like brushing

your teeth or taking a shower - that can and should be sustained throughout

life. "

The researchers also found that age plays a factor in the mechanisms

involved in age-related decline in aerobic power. The investigators report

that in middle-aged adults the mechanisms responsible for decline in

cardiovascular capacity are directly related to peripheral oxygen

extraction, the body's ability to receive, take up and use oxygen.

In the 1966 study, the then 20-year-old volunteers improved their maximal

ability to perform exercise by increasing the amount of blood that the heart

could pump, and by increasing the amount of oxygen that could be extracted.

In the present study the volunteers were only able to increase the amount of

oxygen the muscles extracted.

" This difference may reflect a reduced plasticity of heart muscle as

compared to the skeletal muscle due to aging. Though it is not clear if an

even longer period of training might have had different effects, " Levine

said.

Other research team members include three of the original investigators,

Drs. Gunnar Blomqvist, professor of internal medicine and physiology and

director of the National Aeronautics and Space Administration's Specialized

Center of Research Training in Physiology at UT Southwestern; Jere ,

clinical professor of internal medicine and physiology; and Bengt Saltin,

director of the Copenhagen Muscle Research Centre in Denmark.

Other co-investigators of the 1996 study include Dr. Snell, associate

professor of internal medicine, and Dr. Jon on, associate professor

of physical therapy.

The endurance tests were performed by technicians at the Institute for

Exercise and Environmental Medicine at Presbyterian.

The researchers dedicated the paper to Dr. Carleton Chapman, who initiated

the original study 35 years ago. He died last December. Chapman was chief of

cardiology at UT Southwestern and later became dean of Dartmouth Medical

School.

###

This news release is available on our World Wide Web home page at

http://www.utsouthwestern.edu/home_pages/news/