Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Good news: As you age, leg blood vessels adapt so you can still exercise without fainting

06.10.2004


The "fight or flight" mechanism is one of the best-known physiological responses. It increases our ability to respond to stressful situations. One way to look at exercise – physiologically -- is as a non-life-threatening example of a stressful situation. Think about it: When we exercise, our heart and breathing rates rise rapidly and blood vessels in our limbs dilate in order to deliver more oxygenated blood to our working muscle cells. The rapid rise in blood flow to the periphery -- especially to the legs -- can create a "heady" feeling, which reflects a temporary drop in blood pressure. This stimulates sympathetic nerves throughout the body to release substances that constrict blood vessels, even those vessels that feed working muscles.

Blood vessels in our leg muscles must respond to both dilating and constricting substances to meet the competing demands of muscle oxygen delivery and maintenance of bodily blood pressure, so we don’t faint! It’s a balancing act that could change with advancing age.

David Proctor and Urs Leuenberger and physiology student Dennis Koch, researchers at Pennsylvania State University and Hershey Medical Center, studied this possibility by manipulating the activity of the sympathetic nervous system in healthy older and younger men undergoing a moderate level of leg (cycling) exercise. They used a simple, but powerful sympathetic stimulus -- plunging a hand into a bucket of ice while still cycling -- and compared the blood vessel reactions in the legs of both age groups.



Editors note: Proctor is speaking at the American Physiological Society’s 2004 Intersociety Meeting, "The Integrative Biology of Exercise," Oct. 6-9 in Austin. The meeting schedule is at (http://www.the-aps.org/meetings/aps/austin/tentative.pdf). The complete program, including abstracts, for the entire meeting is available upon request to members of the media.

Arrangements to attend the meeting, and for on-site or telephone interviews, can be made through APS with Mayer Resnick (cell: 301.332.4402, mresnick@the-aps.org) or through Stacy Brooks at 301.634.7253 (sbrooks@the-aps.org). From Oct. 6 (2 p.m.) to Oct. 9, the onsite phone number in Austin is 512.482.8000, room 602, or 512.682.2950 direct.

Leg blood supply in old age important to maintain lifestyle

Results of the Proctor-Leuenberger-Koch study suggest that the mechanisms controlling blood vessel "tone" in exercising muscles may be altered by age in humans. "The augmented constrictor response seen in legs of older men could be a compensatory mechanism for their reduced level of cardiac output during exercise," they reported. In other words, older adults may require a higher level of vascular "restraint" to preserve systemic blood pressure during exercise, Proctor said.

"We expected the blood vessels in the older men to constrict less (relative to younger men) during cold stimulation, based on previous research in older animals and humans under resting conditions," Proctor said. But leg vessels of the older men constricted more, perhaps as a compensation for their reduced level of cardiac output. This indicates that the balance between vasodilation and vasoconstriction in exercising muscle may change with age.

Proctor noted that his laboratory group "is one of the first to systematically study the impact of aging on blood flow to exercising muscle in healthy humans." It’s important to study how healthy people age, he noted, "because keeping our rapidly expanding older population healthy will reduce the burden on our health-care system" as well as contribute to enhanced independence and quality of life in these individuals. Understanding the mechanisms by which blood flow to exercising muscles is altered with advancing age will also help us target interventions aimed at improving exercise tolerance in older adults, he said.

Next steps and funding: The researchers will be conducting similar experiments in women (both on estrogen replacement and not). They plan to study the mechanisms underlying age-related changes in vascular responsiveness to sympathetic stimulation; and to examine the importance of sympathetic outflow in regulating vascular tone and oxygen delivery to exercising muscles. Research is supported by the National Institute on Aging.

Mayer Resnick | EurekAlert!
Further information:
http://www.the-aps.org

More articles from Health and Medicine:

nachricht NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>