Many of us treat a long lie-in as a reward after a tough week. For some, though, sleeping ten hours a night is simply the norm. The question is whether that is good for the body or a quiet warning.
Health authorities draw a line that may surprise you.
The American Academy of Sleep Medicine and the Sleep Research Society recommend that adults aged 18 to 60 sleep 7 or more hours a night on a regular basis.
Most sleep specialists treat 7 to 9 hours as the sweet spot. Sleeping well beyond that, especially 9 or more hours every night, is linked to a long list of health risks in large observational studies.
Also read: Daily fiber supplement eased knee arthritis pain in six-week trial
What long sleep is linked to in large studies
A 2025 meta-analysis in GeroScience pooled 79 cohort studies.
People regularly sleeping 9 or more hours a night had a 34 percent higher risk of dying from any cause than those in the recommended range.
Short sleepers under 7 hours had a 14 percent higher risk. The curve is U-shaped. Both ends looked worse than the middle.
These are observational findings. They do not prove that long sleep itself causes earlier death. Long sleep is often a signal that something else is wrong in the body.
Also read: Your tongue may reveal health problems before you notice other symptoms
The link to stroke and type 2 diabetes
A 2020 Chinese cohort study in Neurology followed about 31,750 adults for six years.
Those sleeping 9 or more hours a night had a 23 percent higher risk of stroke than people sleeping 7 to 8 hours.
The risk nearly doubled in people who slept 9 or more hours at night and also napped for more than 90 minutes in the day. In that group the hazard ratio reached 1.85.
A 2024 meta-analysis in Annals of Medicine found a 13 percent higher risk of type 2 diabetes in people sleeping more than 8 hours a night.
Also read: Your first back pain prescription could more than double your opioid addiction risk
When long sleep came with poor sleep quality, the risk more than doubled. The best outcomes clustered again in the 7 to 8 hour group.
When extra sleep is worth a visit to the doctor
Needing a lot of sleep every day is not always just a habit. It can be the body flagging a condition the person has not been diagnosed with yet.
Common causes worth raising with a doctor include obstructive sleep apnea, which often shows up as loud snoring and gasping at night.
Depression, an underactive thyroid, and iron or vitamin B12 deficiency can also push sleep need up.
Also read: How eating fermented foods every day may change your gut and immune health
Some medications do too, from strong painkillers and antihistamines to several psychiatric drugs. Rarer causes include narcolepsy and idiopathic hypersomnia, where daily sleep can stretch to 14 hours or more.
If you consistently sleep more than 9 hours and still wake tired, that is worth mentioning to your primary care doctor. A simple blood test, or a referral for a sleep study, often finds the reason.
Also read: What your hair can reveal about your thyroid, iron and stress levels
This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.