An interesting study by a team from Harvard and University of Athens Medical School suggests that mid day napping is actually good for men.
This study was conducted among 23,681 healthy adults for a period of six years. It was found that people who had their afternoon siesta at least thrice in a weak for thirty minutes had a 37% less chance of dying due to cardiac arrests and other heart related problems. Diet, smoking and exercise were also considered for this research.
Although this may not be possible for everyone, sleeping for a few hours after the lunch break is reported to have a good effect on other factors as well. Perhaps the sleep invigorates the body and the person is able to handle stress better when his body is rested.