It really is that simple: choose happiness, live longer.

A British study of 3,853 people aged 52 to 79, published October 31, 2011, in the “Proceedings of The National Academy of Sciences,” showed that “those who reported feeling happiest had a 35% reduced risk of dying compared with those who reported feeling the least happy.” (USA Today, November 31, 2011, p. 2a). Instead of relying upon recollection, the study asked them to rate their feelings five times during one specific day. Five years later, researchers examined the group for mortality rates and correlated the rates with the reported levels of happiness.

Happiness (and its close and often overlooked cousin, contentment) is very much a matter of what we choose to focus on, where we choose to put our energies. Don’t believe me? Do an experiment.

Spend one day solely focused on what is wrong with your life—your problems, what could be better, should be better, how unfair life is, how you are not appreciated at work or at home. This is how too many people spend too much of their time! Call it your Frown Day.

Spend the next day with a smile on your face and a cheerful greeting for everyone who comes your way. Think about all the blessings in your life, all the people and things in your life you would miss if they were gone. Banish any negative, judgmental, or downer thoughts. Walk briskly, with energy and purpose. Focus only on the sunny side of the street, keep your head up high, and smile, smile, smile, as mood often follows actions. This is your Smile Day, your Happy Day.

Monitor and record your energy levels and moods. No doubt about it, your smile day will be a much better day.