No one can dispute the restorative value of sleep. Yet, when it comes to the amount of sleep you need, more isn’t necessarily better. A growing number of studies have found that oversleeping can actually contribute to many of the same health problems experienced by those who are routinely sleep-deprived. (3)

How much sleep do you actually need? According to research, seven to nine hours of sleep per night is recommended for adults. (8) However, approximately 4% to 6% of individuals worldwide habitually oversleep. (11) This not only contributes to an array of health problems, but according to an analysis of 16 studies, it may also increase the odds of early death. The researchers conducting this review found that, while people sleeping less than five to seven hours a night had a 12% higher risk of premature death, those sleeping more than nine hours per night were 30% more likely to die prematurely from any cause. (4)

Continue reading to learn more about what causes this lesser-known sleep disorder, how oversleeping can affect your health, and tips to help you reset your sleep schedule.

Did you know?
Adults who oversleep often report increased fatigue, irritability, and lethargy. This could trigger the desire to sleep more, potentially perpetuating an unhealthy sleep cycle. (14)

Image of woman sleeping

If you routinely sleep for more than nine hours per night, you may be suffering from hypersomnia or excessive sleep disorder.

What causes excessive sleeping?

Hypersomnia is the clinical term for excessive or prolonged sleep. Individuals with the condition not only sleep longer, they may have trouble waking up or staying awake during the day.

There are two types of hypersomnia: primary and secondary. Primary hypersomnia is thought to be caused by a dysfunction in the hypothalamus, a small part of the brain that governs sleep-wake cycles. (2) Secondary hypersomnia is the result of factors that can interfere with quality restorative sleep, such as:

Oversleeping symptoms

Daytime napping and difficulty waking up are the most common signs of hypersomnia. However, according to the National Institute of Neurological Disorders and Stroke, chronic oversleeping can also cause other symptoms that can negatively affect your daily life, including:

  • Anxiety
  • Decreased energy
  • Disorientation
  • Hallucinations
  • Increased irritation
  • Loss of appetite
  • Memory issues
  • Restlessness
  • Slow speech
  • Slow thinking (15)

Like sleeping too little, sleeping too much can increase your risk of chronic health conditions and premature death.

Oversleeping health effects

Occasionally sleeping in won’t likely do you any harm. However, if you routinely oversleep, you could be setting yourself up for a variety of health complications.

Oversleeping and heart disease

Excessive sleep disorder is now being recognized as a risk factor for heart disease. One recent analysis of 2,846 patients showed that 35% of those with coronary artery disease slept longer than seven and a half hours per night. (17) Earlier studies report that oversleeping lowers levels of high-density lipoprotein, sometimes referred to as the “good” cholesterol. It also increases C-reactive protein levels, a marker for inflammation that can contribute to plaque buildup in arteries. (26) Inflammation can also make existing plaque unstable, which may increase your risk of a heart attack or stroke. (16)(19)

Did you know?
Sleeping for more than nine hours per night has been shown to increase the risk of heart attack by as much as 34%. (10)

Oversleeping and cognition

Although sleep is critical for balancing neurotransmitters and processing memories in the brain, studies show that oversleeping can impair both memory and cognition. (18)(27)

Additionally, habitually sleeping for nine or more hours nightly and napping during the day can significantly increase the risk of developing dementia later in life. (1) As part of the Women’s Health Initiative Memory Study, researchers found that older women with a history of oversleeping had a 35% higher risk of dementia compared to those who slept for seven hours per night. (9)

Oversleeping and depression

Depression and oversleeping seem to go hand in hand. Research shows that people with depression are more likely to oversleep. (23) On the other hand, oversleeping may also contribute to depression. One analysis of data taken from the Netherlands Study of Depression and Anxiety found that people who slept for more than 10 hours per night were more likely to suffer from persistent depression. (24)

Diabetes and oversleeping

There are a number of risk factors for type 2 diabetes, such as having a family history of the condition or being overweight. One surprising factor that’s rarely considered is sleep duration. A recent cross-sectional study of 740 adults found that those who slept more than nine hours per night were more likely to have impaired glucose tolerance or type 2 diabetes compared to those sleeping seven to eight hours. (6)

This connection appears to be true for both men and women. One observational study involving more than 59,000 women over the age of 55 reported that those who routinely slept for nine or more hours had a 15% higher risk of developing diabetes. (5) Another study of men taking part in the Massachusetts Male Aging Study found that the oversleepers were three times more likely to develop diabetes compared to those who slept seven to eight hours. (28)

Obesity and oversleeping

Studies have consistently found that overweight and obese individuals report oversleeping. (7)(20) A Dutch study of about 1,000 people reported that sleeping more than eight hours per night over multiple consecutive nights in a controlled environment increased the risk of obesity as much as 193%. (25) Other research has linked oversleeping with a 21% increased risk of obesity over the course of 10 years or more. (7)

Image of woman holding coffee cup

Good sleep hygiene is essential for overcoming hypersomnia, and it can be as easy as adopting a few smart habits that foster healthier sleep.

How to stop oversleeping

Good sleep hygiene isn’t just reserved for those with insomnia. Implementing sleep hygiene practices can help promote healthy sleep in individuals with many different sleep problems. (22) Visit the Fullscript blog for tips on how to improve the quality of your sleep, avoid oversleeping, and adopt a healthier sleep schedule.

The bottom line

Getting high-quality sleep is key to optimal health. However, too much of a good thing can be just as detrimental as not enough. If you aren’t able to stop oversleeping on your own, consult your healthcare practitioner to help address any underlying health conditions and provide additional strategies to overcome this challenge.

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