Sleep Duration in Tokyo Versus Other Major Cities

I saw a report about sleep deprivation from the World Sleep Federation, which occurred in Kyoto in October 2011. The report was about a joint study between Stanford University and Ajinomoto Compnay, a Japanese foodmaker that sells a sleep supplement called Glyna. The study was a survey of 180 office workers, aged 30 to 60, from Tokyo, Paris, New York, Shanghai, and Stockholm. The Tokyo office workers averaged only 6 hours of sleep each night, with the National Sleep Foundation recommending 7 to 9 hours as ideal. Only 23% reported getting more than 7 hours of sleep each night. The workers attributed their sleep difficulties to work and personal stress, outdoor noise, the weather, and other reasons. The Tokyo workers got 36 minutes less sleep than New Yorkers and 54 minutes less than Parisians.

It could be that the Tokyo workers really do get the least amount of sleep among the 5 cities surveyed. It also could be that Japanese workers are getting more sleep than they think, and are just especially poor at judging their own sleep amounts. Or, there could be bias in this study since it was sponsored by a company that makes a product to help people sleep. If the Japanese really are getting that little sleep, could it be that their culture values sleep deprivation because it could mean they are spending more time at work? Unfortunately, sleep deprivation is unhealthy and perhaps an educational campaign might improve sleep duration in all office workers.