We are all familiar with the basic guidelines for good health: exercise, eat right – more fruits and veggies, less red meat, more fish, fewer calories, more fiber, less sugar, don't smoke, don't abuse alcohol or drugs. If people would follow these guidelines and maintain an optimal weight, many health problems would be greatly diminished.

But there is another dimension to our health. How we think and feel, how we interact with others, and the kind of activities we spend our time engaged in can have a huge impact on our physical health.

There have been many conflicting theories of psychology, and each one can lead you to practice very different ways of thinking, behaving and interacting.

A Freudian would have you spend hours free associating about memories and fantasies, absorbed in your internal process, with an emphasis on your past.

A Reichian would have you express your feelings − your anger, your pain, your joy, your love − as a primary focus. Such a focus can have people expressing warmth, affection and joy in a very endearing fashion; and it can lead people to yell horrible things at one another in the name of supposed honesty and authenticity.

Such a focus can also lead you to value your feelings as a primary guide rather taking them as information to be considered and integrated with clear thought.

A Behaviorist might have you structure your life with rewards and punishments to steer you toward your goals, while downplaying the more creative flow of life. B.F. Skinner didn't believe there was anything going on inside a person of any particular interest, anyway. But, as Martin Seligman has said, "Skinner was very good with pigeons, not so good with people."

If you take advice from these or from any of a multitude of other psychological theories, you may or may not find yourself living a better life. There is a lot of conjecture, imagination and confirmation bias in psychology, and it can be hard to find the gems of useful wisdom from among the piles of wishful thinking.

Some criteria I use to judge what is helpful and what is not is how it affects a person's happiness, their relationships and their resilience. Do they function better? Are they better able to enjoy the company of family and friends? Does this help them to be more effective and to live a better life?

It's also nice to have some research that serves to measure some of these criteria. Fortunately, over the years there has been a great deal of very good research that is beginning to show some clear and consistent guidelines for how to practice psychological health, and live a happier and more fulfilling life.

It has also shown some practices that can lead to a physically healthier life.

There is a clear difference, for example, between people who are more optimistic or more pessimistic. Optimists have greater longevity − living an average of about eight years longer than pessimists. They have healthier hearts, more resilient immune systems and even have fewer bad events happen to them − because they take active steps to anticipate and avoid them.

Optimists tend to practice healthier behaviors − for example, they tend to give up smoking, while pessimists don't. The skills of optimism are also a powerful inoculation against depression.

Optimists tend to be more effective in general because they tend to look for solutions to problems, while pessimists tend to look for problems in the solutions.

Optimists tend to have better social support, because people tend to stay in contact with optimists longer. As Chris Peterson (of The University of Michigan) told a group of us, "Misery loves company, but company does not love misery."

From the ongoing Harvard Longitudinal Study that has followed men over six decades, there was no difference in health up to age 40, but from ages 40-50, optimistic men stayed healthy while pessimistic men began to get sick and die − usually from heart problems. If they had a second heart attack, it was correlated with pessimism, not the traditional health indicators such as cholesterol or high blood pressure.

(The director of the study, Harvard professor George Vaillant, MD, shows how to apply it to your own life in his marvelous book, Aging Well: Surprising Guideposts to a Happier Life from the Landmark Harvard Study of Adult Development.)

Optimism is only one element of a happy life, but it is the easiest one to improve. While some people are naturally more optimistic than others, it is possible, by practicing some fairly simple skills over time, to become more optimistic. (I have lots of ideas for doing this if you sign up at www.drjoelwade.com.)

Conscientiousness − the propensity to follow socially prescribed norms for impulse control, to be task and goal directed, to make plans, to delay gratification − leads to greater longevity and better health. This is true also for the spouse of a more conscientious person, whose health and longevity improve by virtue of their mate's virtue, regardless of their personal practice (!).

Another quality that can affect your health is how many positive emotions you enjoy in your daily life. Positive feelings tend to act as an antidote to negative feelings and experiences. A ratio of 3:1 positive to negative feelings is the tipping point where positive emotions come more easily and the benefits really start to take hold.

Positive emotions relate to longevity and cardio-vascular health, as well as stronger immune functioning, lower neuroendocrine and inflammatory activity, fewer symptoms of illness, and less pain. Positive emotions also lower the likelihood of hypertension and diabetes mellitus, risk of stroke, and even susceptibility to the common cold.

Positive emotions have also been shown to counteract depression following a crisis, and minimizing depression can have a very positive effect on your health. Depressed people are much more likely to have heart problems, and depression itself can make it difficult to do the things that can improve your overall health and well being.

There are skills that can counteract depression and gratitude is one of these. The simplest intervention that has been shown to both increase happiness and decrease depression is to simply think of three good things that happened at the end of each day, and why they happened.

Practicing forgiveness, avoiding holding grudges and decreasing hostility also have a positive effect on the health of your heart.

The bottom line is this:

Practicing optimism, conscientiousness, positive emotions, gratitude, and forgiveness can significantly improve the quality of your physical health beyond the better known steps of exercise, diet, not smoking, and not abusing alcohol or drugs.

My website and books are full of things you can practice to live a happier, more fulfilling life. Many of these practices can lead you to a physically healthier life as well. That's a nice combination, and it makes a strong moral and medical case for striving toward a happier life.