The recommended amount of sleep for an adult person is 7 hours per night, and routinely sleeping less might be risky. In the research project, data regarding civil servants sleeping habits was collected between the years 1985-8 and 1992-3; the civil servants mortality rates were then checked in 2004. Other factors like age, BMI (body mass index), smoking habits, physical condition, etc. were all taken into consideration. The results showed that the mortality rate of people whose sleeping period decreased from 7 hours a night in the years 1985-8 to 5 hours a night (or less) in the years 1992-3, was 1.7 times higher than the mortality rate of the people who had continued sleeping the recommended 7 hours per night. Cardiovascular problems were the most common cause of death in those persons who had slept less than 7 hours a night.
It is well known that modern society encourages people to sleep less, and many people do not get enough sleep. This latest study has proven there is a connection between insufficient sleep and high mortality rates.
However, the scientists also found that sleeping more than 7 hours a night may also be bad for us. Among the civil servants who increased their nightly sleeping period from 7 hours per night to 8 hours per night or more, the overall mortality rate more than doubled! In this case, cardiovascular problems did not seem to be the main cause of death. The scientist are still trying to establish what lies behind these findings, and what is the true reason for these high mortality rates in well-rested people. In any case, based on these results, it seems clear that sleeping too much is also not recommended.
The Warwick research project produced interesting and potentially important findings regarding the connection between sleeping habits and mortality rates. Although there is much work to be done in this field, we might all need to start considering our sleeping habits more carefully.
More information on the project can be found in the University of Warwick news & events site.
Update: TFOT recently reported that In an article published in 2012, researchers from the University of Notre Dame discovered that going to sleep just after learning new information can be the best way to learn new information.