The huge number of people in this study gives it power. However, the happiness concept is not a standard one when is self-defined and the result of this study is opposable to others previously developed. Some observers noted that measuring emotions is more nuanced and complex than simply declaring happiness or unhappiness. This is why more research is needed .to exclude doubts. Psychologically at least, people are still convinced that stress causes heart attacks and this could even have an influence in their health condition. Another important observation: due to the exclusive women participation in the study it is not clear whether the findings apply to men.