Most people are familiar with the famous story of Goldilocks and the three bears. Goldilocks, upon finding three bowls of porridge, noted that one was too hot, one too cold and the last just right. When it comes to sleep, just as in fairy tales, achieving a middle ground can be crucial to good outcomes.

The Modern Problem of Sleep

Modern people have a variety of conveniences, but we struggle with basic human habits more than ever. Nowhere is this more apparent than in the area of sleep. Many people today are not getting enough sleep, and others are sleeping on irregular schedules. Our world seems set up to prevent sleeping well, with light pollution on every street and a smartphone in every hand.

Although many people find it difficult to get enough sleep, others have just the opposite problem. Some people actually sleep too much. Although this may seem impossible to the sleep-deprived among us, there actually is such a thing as getting too much sleep. Unfortunately, getting too much sleep can have serious health consequences.

The Health Effects of Sleeping Too Much

How much sleep is too much? Although there are slight differences in opinion, sleep experts generally agree that seven to nine hours is optimal. Anything more than this is generally considered too much. However, people who get around seven hours of sleep seem to be the healthiest overall.

Most people will not naturally sleep too much; they wake once they have gotten just enough slumber. Only around two percent of the population can consistently get more than nine hours of sleep. For reasons we do not completely understand, these people appear to be at higher risk of a variety of diseases.

People who sleep more than nine hours a night consistently have higher rates of obesity, heart disease, stroke and diabetes. They also report higher levels of pain, inflammation and cognitive impairment. Sleeping too much also has been correlated with mental illnesses such as depression. Last, people who get more than nine hours of sleep are at risk of developing chronic illnesses such as Alzheimer’s disease late in life.

Could Oversleeping Lead to Premature Death?

Because sleeping too long can lead to an increased risk for a variety of serious diseases, it is not surprising that it has also been linked to premature death. In fact, people who sleep more than ten hours per night are more than 30 percent more likely to die an early death.

However, this increase in mortality is not merely due to stroke and other known complications of excessive sleep. Getting too much sleep has been linked to an increase in all-cause mortality. This means that people who sleep too much have an increase in death from accidents and other causes of death that are not related to known risks such as stroke and heart disease.

The Chicken or the Egg?

Researchers note that we do not currently understand the nature of the relationship between excessive sleeping hours and disease. There is no clear cause-and-effect, no known physiological process involved. As Dr. Vsevolod Polotsky of John Hopkins School of Medicine notes, “we don’t exactly know the cause-and-effect. It probably works the other way, that when you are sick, it leads to more sleep time.”

Indeed, it may not be that too much sleep causes early death, but that higher sleep needs are an indication of illness. Regardless of the nature of the relationship, people who find themselves consistently sleeping more than nine hours a night should discuss the matter with their physician. There are several treatable health problems, such as sleep apnea, that can increase sleep needs. Like apnea, many of the diseases that increase sleep requirements can cause chronic illness if not diagnosed and treated.

Finding the Perfect Balance

Getting the right amount of sleep should not be difficult. In general, if you sleep seven to nine hours of sleep a night and wake up feeling rested, you are getting the right amount. If you find you often need more than this, or that you are consistently tired after getting this amount, you may have an underlying health problem. In this case, most doctors recommend getting a sleep study to ensure that you are sleeping adequately and going through different phases of sleep in a way that contributes to resting. If you are sleeping well and still needing more than nine hours, other testing can help to identify the cause.

It is important to get enough sleep. However, if you find that you need more sleep than is reasonable, it is important to talk to your physician. Although some people simply need more sleep than others, research suggests that too much sleep may be an important warning sign that something is awry with your health.