Research Studies

Key studies linking sleep with productivity, health and safety.

Key Productivity Study

Sleep Deficit: The Performance Killer, C.A. Czeisler, B. Frye, Harvard Business Review, 22nd October 2006

Dr Charles Czeisler, Professor of Sleep Medicine at Harvard Medical School, points out that a week of sleeoing four or five hours a night impairs performance to the same extent as legal drunkenness. “We know that 24 hours without sleep or a week of sleeping four or five hours a night induces an impairment equivalent to a blood alcohol level of .1%. We would never say ‘This person is a great worker! He’s drunk all the time!’ yet we continue to celebrate people who sacrifice sleep.”

Key Health Study

The Association Between Sleep Duration and Weight Gain in Adults. A 6-year Prospective Study from the Quebec Family Study, J-P. Chaput, J-P. Despres, C. Bouchard, A. Tremblay, Sleep, Vol. 31, No. 4, 2008

In this study of 276 adults between the ages of 21 and 64 over the course of six years the study split subjects into three groups: short sleepers (5 to 6 hours), average sleepers (7 to 8 hours) and long sleepers (9 to 10 hours). They found that over the six years short sleepers were 35% more likely to experience a weight gain of 5 kgs and that short sleepers were 27% more likely to develop obesity.

Key Safety Study

Behavioral and Physiological Consequences of Sleep Restriction, S. Banks and D. Dinges, Journal of Clinical Sleep Medicine, Vol. 3, No.5, 2007

In this study of healthy adults individuals were split into groups who were allowed either 4 hours of night time sleep, 6 hours or 8 hours. When tested after 14 days of sleep restriction those in the 4 hours sleep group were 14 times more likely to make an error in testing versus their baseline performance when well rested. The six hour group made 11 times more errors versus baseline, whilst the 8 hours group performed consistently well, despite some decrement.