SAEDNEWS: Sleeping for more than 9 hours in adults is considered excessive sleep and is associated with an increased risk of stroke and heart disease.
According to Saednews, Many people believe that the more they sleep, the better it is for their health. However, recent scientific research shows that this belief is incorrect. Excessive sleep can be just as harmful as insufficient sleep. This article provides a scientific answer to the question of what counts as oversleeping and what health effects it may have.
According to the guidelines of the American Academy of Sleep Medicine, healthy adults need 7 to 9 hours of sleep per night. People who regularly sleep more than 9 hours are classified as “oversleepers” or “long sleepers.”
It is important to note that occasional long sleep (for example, after a stressful week or illness) is normal. The concern arises when oversleeping becomes a consistent pattern and the person still feels tired even after 10 hours of sleep.
Research shows that the relationship between sleep duration and health follows a U-shaped curve. This means both short sleep (less than 7 hours) and long sleep (more than 9 hours) are associated with increased health risks. People who sleep around 7 to 8 hours per night tend to have the lowest rates of illness and mortality.
Multiple scientific studies have linked regular oversleeping with serious health risks:
A 2023 study published in the journal Neurology found that sleeping more than 9 hours per night increases the risk of stroke by up to 167%.
Research published in the American College of Cardiology (2019) showed that individuals who regularly sleep 10 hours have about twice the risk of heart attack compared to those who sleep 7–8 hours.
A large 2021 study published in JAMA found that the lowest mortality rate occurs in people who sleep 7 hours. Both shorter and longer sleep durations were associated with increased risk of early death.
Researchers at Fudan University (2022), published in Nature, reported that 7 hours of sleep is optimal for cognitive performance and mental health. Sleeping less or more than this amount is associated with reduced cognitive abilities and a higher risk of dementia. Oversleeping more than 9 hours may make the brain appear up to 2 years older than the person’s actual age.
Scientific reviews show that regular oversleeping is associated with a 26% higher risk of type 2 diabetes. People who sleep more than 9 hours tend to have higher fasting blood sugar levels and increased insulin resistance.
Excessive sleep is linked to a 25% higher risk of cardiovascular disease and a 24% higher risk of coronary artery disease.
Oversleeping can disrupt hunger hormones such as ghrelin and leptin, increasing the risk of weight gain and obesity.
Oversleeping is generally defined as sleeping more than 9–10 hours per day on a regular basis in adults.
You may be experiencing oversleeping if you notice:
Regular sleep of more than 9–10 hours per day
Feeling tired or sluggish even after long sleep
Difficulty waking up in the morning
Brain fog and reduced concentration during the day
Morning headaches (especially in women)
Frequent need for daytime naps
Mood changes and irritability
Oversleeping is often a sign of an underlying condition. Common causes include:
Depression and mood disorders (most common cause)
Sleep apnea (breathing interruptions during sleep)
Hypothyroidism
Anemia
Autoimmune diseases
Certain medications (e.g., antihistamines, some antidepressants)
Narcolepsy and other sleep disorders
Poor sleep quality (frequent nighttime awakenings)
Diabetes and metabolic disorders
Sleep needs vary with age:
Infants and children: 9–12 hours
Teenagers: 8–10 hours
Adults (18–64 years): 7–9 hours
Older adults (65+ years): 7–8 hours
If you feel you are sleeping too much, consider these strategies:
Maintain a consistent sleep schedule
Increase morning exposure to sunlight
Engage in regular physical activity
Avoid caffeine and alcohol close to bedtime
Limit screen use before sleep
Keep your sleep environment dark, quiet, and cool
Check vitamin D and iron levels if fatigue persists
Consult a healthcare professional if:
You sleep more than 9 hours and still feel tired
Your sleep pattern changes suddenly
You experience symptoms like chest pain, palpitations, or shortness of breath
You have severe depression or anxiety
Your sleep is frequently interrupted and of poor quality
Oversleeping is scientifically defined as sleeping more than 9 hours per day for adults. Regular excessive sleep is associated with increased risks of heart disease, stroke, diabetes, obesity, cognitive decline, and premature death. If you consistently sleep too much and still feel fatigued, it is important to investigate underlying causes with medical support. Sleep quality is just as important as sleep quantity. The optimal goal is 7 to 9 hours of good-quality sleep per night.
