Health wise, it is recommended that an individual should get not more than 7 to 9 hours of sleep at a go. However, some people overstretch this sleep duration and sleep for up to 10 hours or more. Studies have therefore shown that these individuals who sleep more than the recommended sleep duration are liable to develop one form of health complication or the other.
Of course, this does not mean that in some cases where an individual may need lots of sleep, such person is putting their health at risk. Recovery from a jet lag or sickness with sleep is fine, but for the people who always sleep for up to 11 hours or more are at huge risks.
What Science Says
Research carried out at the Faculty of Medicine of Université Laval found that too much sleep, just as much as too little sleep, could cause diabetes in patients. In a study which spanned six years, using 300 patients as reference cases, 20% of these patients developed diabetes or some other type of impaired glucose tolerance. When compared to patients who got the recommended sleep duration, these patients were 2.5 times more likely to develop the disorder than the patients who got the recommended amount of sleep.
When an individual sleeps too much, that person is at risk of developing stroke. According to another study, the risk of stroke is even higher than that of diabetes if a person sleeps excessively, compared to someone who sleeps less. This study tracked the sleep habits of over 9000 adults for close to 10 years. After taking other factors that could cause strokes in consideration, it concluded that those who sleep for more than ten hours every night were prone to developing a heart disease.
Also, excessive sleep is a medical disorder, so if an individual sleeps for more than 10 hours every time, that person should seek medical advice. If a person sleeps too much, the problem may be the bed on which he or she is sleeping. For example, the mattress could be faulty or sagging. So in that case, it would be an excellent idea to invest in a new mattress.