Less active people may live longer?

Less active people may live longer?

A sedentary lifestyle may prolong lifespan, a new study on mice suggests.

Female mice with a high life expectancy are less active and less explorative. They also eat less than their fellow females with a lower life expectancy, researchers said.

The study suggests individuals with a greater life expectancy will express reactive personality traits and will be shy, less active and less explorative than individuals with a lower survival expectation, researchers said.

Behavioural biologists from the University of Zurich reveal that there is a correlation between longevity and personality for female house mice, and a minimum amount of boldness is necessary for them to survive.

Risky behaviour can lead to premature death - in humans. Anna Lindholm and her doctoral student Yannick Auclair investigated whether this also applies to animals by studying the behaviour of 82 house mice.

They recorded boldness, activity level, exploration tendency and energy intake of female and male house mice with two different allelic variants on chromosome 17, thereby testing predictions of "life-history theory" on how individuals invest optimally in growth and reproduction.

Female mice of the t haplotype, one of the two genetic variants on chromosome 17, are known to live longer. The t haplotype in house mice is a naturally occurring selfish genetic element that is transmitted to 90 per cent of the offspring by t carrying males.

Embryos that inherit a t copy from both parents, however, die before birth. With his experiment, Auclair wanted to investigate whether there was a correlation between this selfish genetic element and the personality of the mice.

The researchers reveal that the longer-lived t haplotype females are less active than the shorter-lived non-carrier females. They also consume less food, are less explorative and thus express reactive personality traits favouring cautiousness and energy conservation, as predicted by theory.

"For the first time, we report personality traits associated with a selfish genetic element that influences life expectancy" says Auclair.

According to researchers, female mice with a longer life expectancy follow the strategy "live slow, die old" whereas those with a shorter life expectancy live according to the principle "live fast, die young."

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