Glass half-full: how I learned to be an optimist in a week

Optimists have fewer strokes, sleep better and live longer than pessimists. But how do you change your outlook? By embracing your Best Possible Self, keeping a gratitude journal - and changing your narrative

I've been called many things in my life, but never an optimist. That was fine by me. I believed pessimists lived in a constant state of pleasant surprise: if you always expected the worst, things generally turned out better than you imagined. The only real problem with pessimism, I figured, was that too much of it could accidentally turn you into an optimist.

But accidental optimism is not one of the known dangers of pessimism, a list that does include career impairment, poor health and early death. Optimism, by contrast, is associated with better sleep and lower levels of cardiovascular disease. One study this year claimed that people who describe themselves as optimists had 35% fewer strokes than those who didn't. Another, published in the Proceedings of the National Academy of Science last summer, found that compared with pessimists, the most optimistic subjects lived 11-15% longer lives on average.