Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Everybody dance: The energy you use won't shorten your life

10.10.2006
The theory that animals die when they've expended their lifetime allotment of energy may be reaching the end of its own life, according to a study presented at The American Physiological Society conference, Comparative Physiology 2006.

However, the longitudinal study leaves open a newer form of the theory -- that antioxidants help prolong life by limiting the damage that oxidative stress can cause to cells.

"These findings join a growing body of evidence suggesting that lifetime energy expenditure per se does not underlie senescence," wrote Lobke Vaanholt, Serge Daan, Theodore Garland Jr. and G. Henk Visser in a summary of the study presented at Comparative Physiology 2006: Integrating Diversity. Vaanholt, Daan and Visser are from the University of Groningen, The Netherlands. Garland is from the University of California at Riverside. The conference takes place Oct. 8-11 in Virginia Beach, Virginia.

A bit of background: One early theory, the rate of living theory, held that every organism has a set amount of energy to expend. Once the animal expended that number of calories, the grim reaper was on the doorstep. Over the years, the theory has become much more sophisticated, but metabolic rate and aging have remained linked, Vaanholt explained.

Decades ago, physiologists discovered that during metabolism, oxygen (O2) can split into single oxygen atoms, known as free radicals. These rogue oxygen atoms can remain on their own or combine with hydrogen atoms to form reactive oxygen species (ROS), which wreak havoc with enzymes and proteins and adversely affect cell function. The faster the metabolism, the more ROS produced, the modern theory goes.

Energy expenditure not the key

In this study the researchers divided the mice into three groups of 100 mice each. Two groups were "runner" mice, that is, mice that loved to run on the running wheels placed in their cages. One group of runner mice had access to running wheels, but the second group of runner mice did not. The third group consisted of regular laboratory mice that had a running wheel.

Vaanholt's team followed 60 mice from each of the three groups throughout their natural lives, nearly three years. They measured wheel running activity and took periodic measurements of body mass.

They found:

- Runner mice that had access to a wheel expended 25% more energy over the course of their lives compared to both the runner group that did not have a wheel and the regular mice

- Both groups of mice bred for running, one group with the wheel and one without, lived about 90 days less than the regular mice

- The regular (non-runner) mice lived longest, 826 days, compared to the runners with a wheel, 735 days and runners without a wheel, 725 days

The rate of living theory would have predicted that the running group that expended more energy would die earlier than the two groups that did not, Vaanholt said. This was not the case. There was no difference in life span between the two runner groups, even though one expended more energy.

In addition, the rate of living theory would have predicted that the runner mice without the wheel and the normal mice would live approximately the same life span because there was no difference in energy expenditure between the two. This was not the case. The runner mice without the wheel died sooner.

"The shorter life span cannot, therefore, be explained by a difference in metabolism," Vaanholt concluded. "There must be something else going on that causes these animals to age and die."

More activity = higher metabolism = more antioxidants?

A second portion of the experiment involved the remaining 40 mice in each of the three groups. The researchers periodically used mice from these three groups to determine energy expenditure, body composition and the antioxidant enzyme levels and protein synthesis in the heart and liver tissues. The researchers selected mice, at two months, 10 months, 18 months and 26 months for this analysis.

Since the group of runner mice that expended more energy lived as long as the runner group that was less active, the researchers tested whether there was a difference in antioxidant production between the two groups. Since metabolic rate rises with activity level and oxidative stress rises with metabolic rate, perhaps the runner mice that expended more energy also produced more antioxidants, the body's defense against oxidative stress, Vaanholt said.

However, the study found no difference in antioxidant levels among the groups, at least in the heart and the liver, regardless of energy expenditure. "We would have expected additional antioxidants among the group of mice that expended 25% more energy, but that was not the case," Vaanholt said.

"We can conclude that the presence of a running wheel resulted in increased daily energy expenditure without a change in lifespan or in antioxidant enzyme activity in the heart and liver," Vaanholt explained.

Further research must examine whether tissues in other areas of the body generated additional antioxidants to help cope with the increased oxidative stress brought on with increased activity and metabolic rate, she said. In addition, future studies may examine whether other mechanisms are at work, including whether activity level is connected to DNA repair rates.

Christine Guilfoy | EurekAlert!
Further information:
http://www.the-aps.org

More articles from Studies and Analyses:

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

nachricht Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>