It's been said that the two most important words in the English language have to do with appreciation: thank you. For years, experts have been studying the positive emotional effects of staying grateful.

Professionals say gratitude is like an emotional reset button: It starts you off in a more positive place than where you were before.

By simply allowing yourself to remember the things that have make you feel appreciative of the life you have, you're taking negative emotion and casting it aside in favour of a much more constructive and affirmative option.

University of California psychology professor Robert Emmons has studied how brain chemistry is involved in the process.

In a study of people 12 to 80 years old, he divided them into three groups-those who would record daily things they were thankful for, those who recorded random events and those that would only record assorted pet peeves and aggravations.

The first group showed a significant raise in improving their sleep and exercise patterns as well as scoring better in standardized happiness tests.

"[Grateful people] feel more alert, alive, interested, enthusiastic. They also feel more connected to others. Gratitude also serves as a stress buffer. Grateful people are less likely to experience envy, anger, resentment, regret and other unpleasant states that produce stress," said Emmons, who has also written two books on the science of gratitude.

Preliminary studies suggest that the left prefrontal cortex of the brain, which is connected to emotions like love, is a key spot. If this proves anything, it's that the body may also produce a hormone that coincides with the incredible feeling of being thankful.

Nevertheless, even if scientists don't fully understand the science behind it; there is no doubt as to how effective gratitude is in changing a person's psychological attitude.

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