Toronto, April 22 (Inditop) Too much or too little sleep exposes you to a greater risk of developing type-2 diabetes.

The risk is 250 percent higher for people who sleep less than seven hours or more than eight hours at night, Laval University researchers concluded after analysing the habits of 276 people over a six-year period.

Type-2 diabetes symptoms are increased thirst and frequent urination, extreme hunger, weight loss, fatigue, blurred vision, slow-healing sores and frequent infections.

Researchers determined that over this time span, approximately 20 percent of those with long and short sleep duration developed type-2 diabetes as against only seven percent of subjects who were average sleepers.

Even when the effect attributable to differences in body mass were taken into account, the risk of diabetes and insulin resistance was still twice as high among those with longer and shorter sleep duration than average sleepers.

The researchers also point out that diabetes is not the only risk associated with sleep duration.

A growing number of studies have shed light on a similar relationship between sleep and obesity, cardiovascular disease and overall mortality.

The authors observed that among adults, between seven and eight hours of night time sleep seems to be ideal to protect against common diseases and premature death, said a Laval release.

However, it seems that fewer and fewer people sleep the optimum number of hours. A survey conducted in 1960 showed that American adults slept an average of 8 to 8.9 hours a night.

These findings were published on the website of Sleep Medicine.