Sitting across the desk, after a minor health scare, my doctor looked me in the eye and said, "We don't want you to go anywhere before you turn 100, did you hear me? Starting today, every day for 15 minutes you visualize yourself full of life, love, gratitude, and blowing out all 100 candles on your cake."

I liked the doctor's prescription, so I invite you to try it. I also liked that a doctor accepted the relationship between mind and health, because there's no doubt that it's our mentality and our attitude that largely determine how long we live.

Let's see: how many cases do we know of people who die shortly after being widowed by the love of their life? Or cases of individuals who, for various reasons, decide they no longer want to live, and the universe grants them the favor: they die shortly afterward? It's the same thing that can happen to people burdened with resentment and bitterness, who inevitably become ill over time. All of which seems to show that our thinking alters our reality.

This doesn't mean we have to decide when we'll leave this world—that's not the point. However, there's no longer any doubt that our mental life—how we perceive the world—can significantly affect our health, for better or worse.

Modern medicine increasingly links attitude, thoughts, and emotions to the ailments we suffer. Furthermore, what I think affects not only me, but the world around me as well. Let's see: a thought is an electrical impulse with information that goes directly to the hypothalamus—the pharmacy that fills prescriptions. There, substances that govern body chemistry are secreted and travel through the bloodstream. This chemistry directly impacts our health.

What do the studies say?

Answer “yes” or “no” to the following questions:

1. Am I as happy as I was when I was younger?
2. Does it seem like things get worse as I get older?
3. Do I have as much energy and vitality as I used to have a year ago?
4. Do I have many plans for the future?
5. Do I expect too much from life?

These are some of the questions asked of a group of 660 senior citizens living in a town in Ohio more than 25 years ago, as part of a study on the relationship between a person's attitude and their longevity. The study was published in the Journal of Personality and Social Psychology y en el libro Chasing Life del doctor Sanjay Gupta.

After more than a quarter of a century, researchers at Yale and Miami universities compared the results of these studies with people's current status; what they found was surprising. Those who had displayed a more positive perception and attitude toward life outlived their pessimistic contemporaries by an average of 7.5 years. This advantage was sustained after the researchers analyzed key factors such as age, gender, socioeconomic status, loneliness, health, and functional level. Those with a better attitude and optimism toward life showed better survival rates regardless of their age, or even if they smoked or had worse health status than the rest of the group.

Researchers have no scientific explanation for these results. They speculate that it may be because optimists are better at weathering adversity, as well as leading a healthy lifestyle and taking better care of themselves when they get sick. They are also likely to have healthier relationships and enjoy being with their friends or social circles.

All of the above impacts the immune system, blood pressure, and hormone production, leading them to conclude that the happier a person is, the lower their heart rate and lower their cortisol (stress hormone) levels. Furthermore, it is now known that 75 percent of our gene expression depends on our lifestyle, and it is up to us to modify it.

So, can the way you choose to view your life change your brain, and can thinking optimistically make you live longer? The answer is a resounding "yes," according to the specialists in the study published in Archives of Internal Medicine en 2006.

Now, if you tend to be a pessimistic person by nature, just remember the old saying: "Assume an attitude and you'll end it." Self-awareness can lead you to take action to modify your behavior, such as getting informed or deciding to abandon your grumpy or fatalistic nature. Of course, I'm not referring to cases of depression—which is a serious matter, and when it occurs, you should consult a doctor for help.

So we can conclude that you decide how many years you want to live.

So, for 15 minutes a day, visualize yourself full of health, surrounded by love, and blowing out the candles on your 100th birthday cake. Did you hear that? Because before that day, we don't want you to go anywhere.