A new study puts evidence behind the old adage that stressful experiences can give a person gray hairs. Scientific data now indicate that prolonged psychological stress might cause a person's cells to age, and possibly die, significantly faster than normal.
Previous research had shown that protein-DNA complexes called telomeres serve as a cell's timekeeper, telling it how long to live. Telomeres protect the ends of chromosomes, much as plastic tips protect shoelaces. Each time a cell divides, enzymes chew off a tiny portion of its telomeres. When the caps are whittled down to nubs, cells cease dividing and soon die.
Scientists have long known that stress can harm a person's health by, for instance, lowering immunity or raising blood pressure. "We wanted to look at some of the molecular underpinnings of why that might be true. No one actually has clear ideas," says Elizabeth Blackburn of the University of California, San Francisco.
Blackburn and her colleagues exam