A study out of Notre Dame University August of 2012 showed that telling the truth when tempted to lie can significantly improve a person's mental and physical health. Investigators sampled 110 people over 10 weeks. Half were instructed to stop telling major and minor lies for the 10 week study. Both groups returned to the lab weekly to complete health and relationship measures and to take a polygraph test to assess the number of major and white lies they had told in the previous week.
The link between lying less and improved health was stronger for the "no-lie" group. They experienced fewer mental health complaints such as feeling tense or disappointed in themselves, and fewer physical complaints such as sore throats and headaches.
By the end of the 5th week, the more truthful group saw themselves as more honest. They found they were more likely to tell the truth about their accomplishments rather than exaggerating and also stopped making false excuses for being late or failing to complete an assignment.
