We all understand that too little sleep can be bad for your health. But did you know the same is true for too much sleep? There is mounting evidence of the vital role that sleep plays in our metabolism and overall health.

Now, new research suggests that getting the right amount of sleep — i.e., seven to eight hours a night — may help you avoid diabetes and live a longer life.

Led by Dr. Jane Ferrie, researchers from the University College Medical School in London studied 10,308 British government workers between 35 and 55 years old and followed them for between 12 and 17 years.

The researchers found that the death rate was higher for people who averaged less than five hours of nightly sleep or more than nine hours.

They found that death rates were higher for people who spent too much — or too little— time sleeping.

The researchers found that the death rate was higher for people who averaged less than five hours of nightly sleep or more than nine hours. They say that age, smoking, BMI (body mass index) and other non-sleep related factors could not have explained the results and concluded that consistently sleeping between 7 and 8 hours per night is best for your health.

The findings of this British study are backed by research from the U.S., which also found that sleeping too much or too little may make diabetes more likely.

This study was conducted by researchers at New York's Columbia University and used data from nearly 9,000 U.S. adults. At the beginning of the study none of the participants had diabetes, but ten years later, 430 had developed the disease.

It turned out that those who were most likely to develop diabetes were the people who reported getting less than five hours or more than nine hours of nightly sleep.

The research is published in the December 13 issue of the journal Sleep.