It might seem counterintuitive to believe that exposing living things to toxic substances would make them live longer, but at low levels that appears to be true.
In a recently published experiment, scientists exposed C elegans roundworms to a substance called plumbagin which is a pesticide. Plumbagin acts by producing free-radicals, dangerous chemical which damage and kill cells.
The trick was to expose the worms to very low levels of the chemical chronically. This way it wasn’t enough to kill them but instead triggered the animal to increase production of internal enzymes capable of defending against free radical damage.
These higher level of protective enzymes then in turn caused the worms to live 13 to 15% longer. The enzymes protected the worms against regularly occurring free-radical damage.
There is reason to believe that an inducer of lifespan in humans – chronic vigorous exercise – may act through a similar mechanism. Exercise induces oxidative metabolism and free radical generation which likely then increases production of protective life-extending enzymes.
Reference (PLoS One. 2011;6(7):e21922)