It looks as if Benjamin Franklin may have been on the wrong track when he advised, "Early to bed, early to rise, makes a man healthy, wealthy and wise".
In a quirky British study, researchers set out to test Franklin's hypothesis by looking at the lifestyles of larks (those who went to bed before 11 pm and were up before 8 am) and owls (those who went to bed after 11 pm and were up at or after 8 am). What they found was that there was little difference between the cognitive performance of the groups; that owls tended to be richer; and that those who spent eight hours in bed had half the relative risk of death from all causes during the study period than did those who spent 12 hours or more asleep.
While interesting, the study's conclusions need to be interpreted cautiously. Cognitive performance is not the same as wisdom. Owls may be richer because they spend longer hours working and those who spent the longest time in bed tended to be the elderly and ill who are at a greater risk of death. Nevertheless, night owls can, it appears, carry on hooting it up without fear of risking their health (BMJ, 1998; 317: 1675-7).