Participants were divided into three groups: those who don't nap, short nappers of 30 minutes or less, and long nappers of 30 minutes or more. Having analyzed the participants' responses to a number of psychological questions, the researchers found that 66 percent of short nappers not only increased their productivity but also felt happier, compared with 60 percent of non-nappers, and 56 percent of long nappers.
On the five-point happiness scale, short nappers had an average score of 3.67, as compared to 3.53 for non-nappers, and 3.44 for long nappers.
Almost 15% more of participants aged 18-30 took naps than those over 50.
"Previous research has shown that naps of under 30 minutes make you more focused, productive, and creative, and these new findings suggest the tantalizing possibility that you can also become happier by just taking a short nap," said psychologist Richard Wiseman of the University of Hertfordshire, pointing out that companies like Google have installed special nap spaces for employees.
Wiseman stressed that while brief naps, from 20 to 30 minutes, are beneficial for health and boost performance, frequent longer dozing is associated with various health risks.
In another study on sleepy military pilots, the US space agency NASA found that taking a short nap while the co-pilot was in control boosted alertness by more than 50 percent.
