http://articles.mercola.com/sites/articles/archive/2008/01/02/body-clock-part-three.aspxResearchers say sudden exposure to light can upset a sleeping individual's 'body clock,' even if snoozing continues uninterrupted. The experts believe their insights into light's effects on the sleep/wake cycle could further research into the treatmentenCommunityServer 2008.5 SP1 (Build: 31106.3070)