Pay attention to this story as if your life depended on it.
That's because thinking about things other than the task at hand can seriously up your anxiety level. Not to stress you out or anything, but that might make you age faster, get sick and die, according to The Telomere Effect: A Revolutionary Approach to Living Younger, Healthier, Longer, a book from molecular biologist Elizabeth Blackburn and health psychologist Elissa Epel.
Blackburn (and two colleagues) won the Nobel Prize in 2009 for the discovery of telomerase, the enzyme that replenishes the bits of DNA on either end of your chromosomes. Those bits are called telomeres, and they're often compared to the plastic caps on shoelaces.
Let those caps wear down, and the laces fray and can't do their job. It's the same with telomeres: Stress makes them shorter. And if they get too short, your cells stop dividing, which leads to pain, heart disease and other health woes - all markers of what the authors dub the "diseasespan." (The idea is that we have a healthspan and a diseasespan during our lives, and people with short telomeres move into their diseasespan earlier.)