A research institute investigated the relationship between the frequency of laughter and health status of about 20,000 people over the age of 65  The results showed that the proportion of unsmiling elderly people who thought their current health was not so good and bad was 1 5 times and 1 8 times higher than that of laughing almost every day,respectively  Elderly people who love to laugh tend to have a higher evaluation of their health
The suffering of illness makes some people's self-health evaluation is not high.
 As a result, they think that elderly people who love to laugh are healthier