Sleeping longer to recover, regenerate or compensate for chronic fatigue seems intuitively beneficial. However, several recent studies overturn this preconceived idea. Beyond nine hours of sleep, the protective effects seem to reverse. By digging into data from large international cohorts, researchers have identified a clear link between prolonged sleep and increased mortality risk. But these figures raise an even broader question. Are we sleeping too much, or is our body trying to tell us something?
The myth of unlimited restorative sleep is crumbling
Sleep is often compared to a natural medicine. We know it is essential for physical recovery, memory consolidation, metabolic balance and even emotional regulation. However, its “optimal dose” seems well defined. According to the Sleep Health Foundation, the majority of adults need seven to nine hours of sleep per night to function properly.
Recent meta-analyses have highlighted that sleeping beyond this range can have adverse effects. The study published in GeroScience this year, which compiles data from 79 cohorts of more than a million participants, shows that sleeping more than nine hours per night is associated with a 34% increase in the risk of all-cause mortality, compared to 14% for those who sleep less than seven hours. Another study published in the Journal of the American Heart Association even establishes a progressive increase in risk with each hour beyond eight hours: +14% at 9 a.m., +30% at 10 a.m., and +47% at 11 a.m. These figures therefore shake up a stubborn idea. The more we sleep, the better we feel.
Sleeping too long could signal a deep imbalance
Long sleep may not be the problem itself. Several researchers insist that it could above all be the silent reflection of an underlying disorder. Patients suffering from chronic pain, metabolic disorders or depression often need more sleep. In these cases, prolonged rest becomes a compensation mechanism.
In the cohorts studied, long-term sleepers also had an increased risk of cardiovascular disease, type 2 diabetes and even psychiatric disorders. Constant fatigue, side effects of certain treatments or poor quality of sleep can cause you to stay longer in bed, without recovering effectively. In other words, time spent in bed does not guarantee restful sleep.
Behind a persistent need for rest, we must sometimes see an alert from the body, and not a simple excess of restorative zeal.
What disrupted rhythms reveal about our health
Excessive need for sleep also varies depending on age, lifestyle and mental health. In adolescents, a duration of eight to ten hours remains physiologically normal. But in adults, regularly sleeping more than nine hours raises questions. Hormonal differences, instability of the circadian rhythm or a lack of physical activity can amplify this phenomenon.
Researchers agree that the quality of sleep matters as much as its duration. It is not enough to lengthen the nights, sleep must be deep, regular, and in phase with our biological rhythms. Going to bed and getting up at set times, exposing yourself to natural light in the morning, limiting screens in the evening, practicing moderate physical activity, are all simple levers for stabilizing long-lasting beneficial sleep.
Sleeping too much is therefore not to be demonized straight away, but to be observed carefully. When this habit sets in without any apparent cause, it becomes a signal to be taken seriously. Listening to what the body expresses through sleep sometimes means anticipating what medical analyzes do not yet detect.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
