Study tells whether colder temperatures affect lifespan

While many believe that animal species live longer at lower temperatures than they do at higher temperatures, a study from the University of Chicago (UChicago) indicates that the extent to which temperature affects lifespan depends on an individual's genes.

The study was conducted in the rotifer, a tiny animal that the researchers have been developing as a modern model system for aging research. The researchers exposed 11 genetically distinct strains of Brachionus rotifers to low temperature, with the hypothesis that if the mechanism of lifespan extension is purely a thermodynamic response, all strains should have a similar lifespan increase.

Nevertheless, the median lifespan increase ranged from 6 percent to 100 percent across the strains, the researchers found. They also observed differences in mortality rate.

The results show that the change in lifespan under low temperature is likely actively controlled by specific genes. "This means we really need to pay more attention to genetic variability in thinking about responses to aging therapies," said Kristin E Gribble of Marine Biological Laboratory at UChicago. "That is going to be really important when we try to move some of these therapies into humans."

The study clarifies the role of temperature in the free-radical theory of aging. The theory, which has dominated the field since the 1950s, proposes that animals age due to the accumulation of cellular damage from reactive oxidative species (ROS), a form of oxygen that is generated by normal metabolic processes.

The study has been published in Experimental Gerentology.