Live fast, die young? Maybe not

Mar 09, 2009

The theory that a higher metabolism means a shorter lifespan may have reached the end of its own life, thanks to a study published in the journal Physiological and Biochemical Zoology. The study, led by Lobke Vaanholt (University of Groningen, The Netherlands), found that mice with increased metabolism live just as long as those with slower metabolic rates.

The theory that fast-living animals die young, known as the rate-of-living theory, was first proposed in the 1920s. The premise is simple: Aging is the inevitable byproduct of . The faster you expend energy, the faster you age, and the sooner you die. It remained a prominent theory of aging until recently, when comparisons across broad animal groups cast doubt on it. For instance, birds have significantly higher than mammals of similar size, yet the birds live much longer.

Vaanholt's study was designed to test the rate-of-living theory among individuals of one species—in this case, mice.

For their experiment, Vaanholt and her team followed two groups of mice through their entire lives. One group's environment was kept at 71 degrees Fahrenheit (22 degrees Celsius), and the other group's at 50 degrees Fahrenheit (10 degrees Celsius). The colder group had to expend more energy to maintain body temperature, and according to the rate-of-living theory, should therefore die sooner than the warm group.

But that's not what happened.

"Despite a 48 percent increase in overall daily energy expenditure and a 64 percent increase in mass-specific energy expenditure throughout adult life, mice in the cold lived just as long on average as mice in warm temperatures," the authors write. "These results strengthen existing doubts about the rate-or-living theory."

The finding is consistent with an experiment Vaanholt conducted previously. That experiment manipulated metabolism in mice through exercise rather than temperature. Mice that expended more energy over a lifetime through exercise had the same as those that did not exercise.

Both studies cast significant doubt on a theory that just may have burned itself out.

Source: University of Chicago

Explore further: Clues to aging from long-lived lemurs

Related Stories

Everybody Dance! The Energy You Use Won't Shorten Your Life

Oct 09, 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 ...

Fever in mice linked to shorter life span

Nov 01, 2007

Mice with shorter life spans use fever to fight infections more than longer living mice, said U.S. researchers who had expected the opposite finding.

Recommended for you

Clues to aging from long-lived lemurs

1 minute ago

When Jonas the lemur died in January, just five months short of his thirtieth birthday, he was the oldest of his kind. A primate called a fat-tailed dwarf lemur, Jonas belonged to a long-lived clan. Dwarf ...

Cats relax to the sound of music

4 hours ago

According to research published today in the Journal of Feline Medicine and Surgery by veterinary clinicians at the University of Lisbon and a clinic in the nearby town of Barreiro in Portugal, music is likew ...

Fruit flies crucial to basic research

6 hours ago

The world around us is full of amazing creatures. My favorite is an animal the size of a pinhead, that can fly and land on the ceiling, that stages an elaborate (if not beautiful) courtship ritual, that can ...

Crete's mystery croc killed by cold snap

6 hours ago

A man-eating crocodile that became an attraction on the Greek island of Crete last year after its mysterious appearance in a lake has died, probably of cold, an official said Monday.

Hunting for living fossils in Indonesian waters

6 hours ago

The Coelacanth (Latimeria menadoensis) was thought to be extinct for more than 60 million years and took the science world by storm in 1938 when it was re-discovered living in South Africa. This fish has ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.