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: Honey bee behavior altered by insecticides

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

Godwits are flexible... when they get the chance

19 hours ago

Black-tailed godwits are able to cope with unpredictable weather. This was revealed by a thorough analysis of the extraordinary spring of 2013 by ecologist Nathan Senner of the University of Groningen and ...

Do you have the time? Flies sure do

May 28, 2015

Flies might be smarter than you think. According to research reported in the Cell Press journal Current Biology on May 28, fruit flies know what time of day it is. What's more, the insects can learn to con ...

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.