Strains of the lab workhorse roundworm C. elegans that lived longer added more time being frail, and had the same portion of their lives being healthy as normal worms. The work has implications for life-extension ideas such as caloric restriction. Dina Fine Maron reports.

 

Living longer doesn’t necessarily mean living better. That’s the lesson from the tiny roundworm called C. elegans, long a workhorse in basic biology lab work. The research is in the Proceedings of the National Academy of Sciences. [Ankita Bansal et al, Uncoupling lifespan and healthspan in Caenorhabditis elegans longevity mutants]

 

In the study, thousands of normal C. elegans competed against strains that live days or weeks longer than their brethren, because of factors like genetic mutations or very low-calorie diets.

 

But a battery of tests to see how the all older worms moved or responded to stress revealed some hard truths: increased lifespan did not usually come with a prolonged period of health and strength. Indeed, the “good times” for each of the worms was roughly the same, regardless of their overall lifespan. In other words, the longer-living worms spent a greater proportion of their lives in a diminished state—with less mobility and stress resistance.

 

Aging worms are not aging humans. But if the findings do extend to people, then life-extension efforts, such as calorie restriction, may not shake out to a better old age, just more years of frailty. With associated healthcare cost increases and quality of life decreases. The researchers suggest that it’s time to start thinking about what they call “healthspan”—and maximizing “healthspan,” rather than just tacking on years of poor quality.