You might have, at some stage, encountered the idea that the lifespan of an animal is related to its rate of energy consumption; i.e., that the faster its metabolism, the shorter an animal lives. I’ve also heard it said that all animals get a certain number of heartbeats in life and the sooner they use them up, the sooner they die. This might explain why an elephant lives longer than a mouse, but new evidence has hammered a fairly convincing nail in the coffin of this theory.

In this press release, Live Fast, Die Young, Maybe Not…, it talks about an experiment whereby two groups of mice were made to live under different conditions of temperature – 22 degrees and 10 degrees Celsius, respectively, the rationale being that the cold mice would have to expend more energy throughout their lives simply to stay warm. The mice were then evaluated as to their longevity.

There was found to be no significant difference in longevity between the two groups.

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. These results strengthen existing doubts about the rate-or-living theory.

So, while I always strongly doubted this theory (how could a parrot live so much longer than a dog?), it still played in the back of my mind that expending a great deal of energy on exercise and whatnot would burn my body out and lead to a shorter lifespan. Hopefully, I can now lay those fears to rest once and for all!