How well you respond to stress predicts how long you will live, at least if you are a little worm, U.S. scientists reported on Monday.

Genetically identical worms responded to stress in greatly different ways — and those with more active stress reactions lived much longer than worms with less active stress proteins, the researchers found. More active stress responses suggest the animal is coping with the stress.

The findings will almost certainly apply to humans in some way, they report in this week’s issue of the journal Nature Genetics.

Shane Rea of the University of Colorado at Boulder tested more than 100,000 nematodes known as Caenorhabditis elegans — a worm favored by scientists because it is easy to work with.

Despite its tiny size, C. elegans is genetically complex and has much in common with “higher” animals such as humans.

They genetically engineered the little transparent worms to carry a jellyfish gene called green fluorescent protein, which glows green under certain light. They tagged this gene to a gene called hsp-16.2, a stress protein found in most organisms that is associated with the health of cells.

The more active the hsp-16.2 gene was, the brighter the worms glowed green and, presumably, the better they coped with stress.

In a typical experiment, the worms that glowed the brightest green lived about 16 days, compared to about three days for those that glowed the most weakly — under identical conditions.

“We have shown it’s possible to predict the life span in an organism on the first day of adult life based on how it responds to stress,” said Thomas Johnson, a professor who helped lead the study.

“This is something that has not been done before, and has implications for human longevity and health.”

This gene now might be useful for predicting how robust an animal is. “We have engineered a single gene to monitor the health of an organism, which is a first,” said Johnson.

More here.