Numerous scientific and psychological studies have shown that being optimistic makes you more successful, helps you deal with problems more effectively, and allows you build stronger, more resilient relationships.

However, there is one downside to being an optimist and it's a doozy: a higher likelihood of dying prematurely. According to a fascinating article in New York magazine, the researchers at the University of Southhampton, led by professor of Cognitive Epidemiology Catherine Gale,

"tapped into the United Kingdom Biobank, a massive set of health data collected between 2006 and 2010 from over a half million U.K. residents aged 37 to 73. In addition to analyzing subjects' neuroticism (based on a personality questionnaire) and self-reported health, the researchers also looked at specific health behaviors (smoking, drinking, diet, exercise), physical attributes (BMI, blood pressure, grip strength), cognitive function (reaction time, mental processing speed), diagnosed diseases (self-reported), and socioeconomic status (education, assets, postal code). On average, each person's data stretched over six years and three months; nearly 5,000 participants died during the data-collection period, which gave their information an especially strong statistical power."

Just to be clear, very few scientific studies cover half-a-million people, so this is research that's impossible to ignore. The surprising findings of this study was that

"people who rated their own health poorly also tended to have higher levels of neuroticism and a lower likelihood of premature death."

In other words, people who are neurotic (i.e. pessimistic about everything) live longer than people who aren't.

I know, I know. That sounds totally crazy. How can pessimists--with all their emotional sturm und drang--be living longer than optimists, who are more likely than pessimists to eat well and exercise, and less likely than pessimists to smoke and drink heavily?

According to neuroscientists, pessimists tend live longer than optimists because they worry more about their health.

Unlike optimists, pessimists (fearing the worst) tend to run to the doctor the moment they experience a symptom of ill health. As a result, pessimists are more likely to discover a serious illness (like cancer) before it reaches the point of no return.

On the other hand, optimists (expecting the best) are more likely to assume that a symptom is "temporary" or "no big deal." As a result, optimists can let symptoms fester until they turn into big problems.

I'm a case in point. Last month I almost died of heart failure because 1) I let my positive attitude convince me that some high blood pressure readings were just a fluke, and 2) I postponed my regular physical for 3 years because I was "sure" I was healthy.

Now, this is not to say that we optimists would be better off if we became pessimists. Quite the contrary. Pessimists create their own personal mini-hell on earth. Who wants to live (longer) like that? Not me, certainly.

Instead, optimists can get the life-extending benefits of pessimism by 1) religiously getting regular physicals and 2) running to the doctor the moment our bodies gives us a warning signal--even when our optimism makes us feel like we're wasting our time.

So here's the rule: be optimistic about life, but when it comes to your health, go pessimist all the way, baby.