Is Oversleeping Bad for You? How Much Sleep Is Too Much

Quick answer: an occasional long sleep, after an illness, a trip or a short week, is usually not a problem. Sleeping more than nine hours in 24 on a regular basis is what the Sleep Foundation calls oversleeping, and long sleep has been linked in observational studies with several health conditions. Those studies show associations, not proof that the extra sleep is the cause. If you regularly sleep long and still feel unrefreshed or sleepy in the day, that pattern is worth raising with a doctor.

Quick Fix / Summary

One or two long nights are normal, especially after short sleep, illness or travel
Most adults need about 7 to 9 hours; regularly sleeping more than 9 is the usual definition of oversleeping
Needing much more sleep on days off often points to a weekday shortfall
Common contributors include sleep debt, sleep apnea, low mood, sedating medicines and alcohol
Studies link long sleep with poorer health, but they cannot show that long sleep causes it
Keep a short sleep diary and talk to a doctor if long sleep is a steady pattern or you still feel unrested

Who This Is For

You regularly sleep 9, 10 or more hours and wonder whether that is harmful
You sleep much longer on weekends or days off and feel you “owe” yourself the rest
You have read scary headlines about long sleep and want to know what the research really shows
You sleep a lot and still wake up tired
You want to know when it is just a busy week and when it is worth a doctor’s visit

This page is about total sleep time across the night. If your question is whether to doze off again after waking early in the morning, see our guide to going back to sleep in the morning.

How Much Sleep Is “Too Much”?

There is no single number that is too much for everyone, because sleep needs vary and change with age. The guidance below gives the ranges that the main health sources use.

Source	What it says
CDC	Adults aged 18 to 60 need 7 or more hours a night; ages 61 to 64, 7 to 9 hours; age 65 and older, 7 to 8 hours
NHLBI (NIH)	Adults should aim for 7 to 8 hours; if you regularly sleep more than 8 hours and still do not feel well rested, talk to your doctor
Sleep Foundation	Oversleeping means sleeping more than nine hours in a 24-hour period; occasional extra sleep is usually not a concern

Sources: CDC, NHLBI and Sleep Foundation. The cut-offs differ a little, so treat them as a guide rather than a pass or fail line. The more useful question is usually how you feel: whether you wake refreshed, stay alert through the day and whether your sleep need has changed recently.

A Long Night Now and Then vs a Steady Pattern

The Sleep Foundation says occasional extra sleep, for example after illness or travel, is usually not a concern. The NHLBI adds that sleeping much more on days off can signal that you are short on sleep during the week. In that case the long sleep is your body catching up, not a problem of its own.

If that sounds like you, it helps to work out how big the shortfall is. Our sleep debt calculator turns a week of logged nights into a number, and can you really catch up on sleep over the weekend explains what lie-ins do and do not repair. The NHLBI also notes that sleeping in can upset your body’s sleep-wake rhythm, which is why a steadier wake time usually works better than a big weekend swing. For a step-by-step reset, see how to fix your sleep schedule naturally.

A steady pattern is different. If you sleep more than nine hours and also have excessive daytime sleepiness, fatigue or brain fog that affects your life, the Sleep Foundation advises seeing a doctor, and it says you can also see one simply because you are concerned about how much you sleep.

Why Some People Sleep So Much

The Sleep Foundation lists several things that can go along with long sleep. None of these is a diagnosis, and more than one can apply at once.

Sleep debt

Weeks of short nights are the most ordinary reason for a long sleep. Once the shortfall is repaid, many people find their sleep length settles back down.

Sleep apnea

Repeated breathing interruptions can fragment sleep without you remembering them, so you spend long hours in bed and still feel tired. If you snore loudly or a partner has noticed pauses in your breathing, read what sleep apnea is and when to see a doctor.

Low mood, depression and anxiety

The Sleep Foundation notes that depression and anxiety are linked with longer sleep, and for some people sleeping far more than usual is part of low mood. Our guide to depression and sleep covers how the two relate and what tends to help.

Medicines, alcohol and cannabis

Sedating medicines, alcohol and cannabis can all increase sleepiness. The Sleep Foundation lists tranquilizers, sleeping pills, antihistamines, certain painkillers and some psychiatric medicines among the sedating drugs, and it says that if you suspect a medicine is making you sleep too much, you should not stop taking it. Talk to the prescriber or a pharmacist instead, who can review it with you. Our article on antidepressants and sleep explains why changes should always go through the prescriber.

Sleep disorders that cause hypersomnia

Conditions such as narcolepsy and idiopathic hypersomnia can involve very long sleep or heavy daytime sleepiness. The Sleep Foundation says some people with idiopathic hypersomnia sleep as much as 14 to 18 hours a day. These are uncommon, and a specialist is the right person to assess them. For the full picture, see excessive daytime sleepiness: causes and when to see a doctor.

What the Research Links to Long Sleep (and What It Cannot Tell You)

The Sleep Foundation’s summary of the research says that long sleep has been associated with obesity, type 2 diabetes, heart disease, stroke, depression, headaches and back pain, and with a higher risk of death. It adds that some research suggests sleeping 10 hours or more a night is linked with nearly double the risk of death. A meta-analysis of 16 prospective studies in the journal Sleep (Cappuccio et al., 2010) found that long sleep was associated with a greater risk of death from any cause, with a pooled relative risk of 1.30 (95% CI 1.22 to 1.38) and significant differences between the studies. That pooled figure is well below “double”, so the size of the link varies between studies and is better read as a modest association.

Those are associations. Most of this research is observational, which means it follows what people report and cannot show that long sleep itself causes any of these outcomes. Several things could be going on: an underlying illness might lengthen sleep and also affect health, poor-quality sleep might lead people to spend longer in bed, or other lifestyle factors might sit behind both. The research does not settle which of these applies to any one person.

The practical reading is modest. If you sleep long on a regular basis, it is a useful signal to ask why, rather than a reason to panic, and it is not something to fix by forcing yourself awake.

What You Can Do

Keep a two-week sleep diary: note bedtime, wake time, how rested you feel and any daytime sleepiness. The Sleep Foundation suggests a diary as a helpful thing to bring to an appointment
Look for a weekday shortfall first: if you sleep 6 hours on work nights and 10 on days off, the long nights may simply be repayment
Keep your wake time fairly steady: a regular wake time, including on days off, supports your body clock
Notice what you take in the evening: alcohol and some medicines can add to sleepiness, so note them in your diary and raise them with a doctor or pharmacist if they worry you
Do not cut your sleep down sharply on your own: if your body needs the hours, restricting them tends to leave you short on sleep, and the better step is to find out why you need them

Common Mistakes to Avoid

Assuming long sleep means laziness: persistent oversleeping can have a medical reason, so it deserves a proper look rather than self-blame
Treating the headlines as a diagnosis: an association in a large study does not tell you what is happening in your own body
Stopping a medicine because it may be making you sleepy: speak to the prescriber first
Ignoring loud snoring or breathing pauses: these can go with long, unrefreshing sleep, so they are worth mentioning to a doctor
Relying on weekend lie-ins to run a permanent deficit: big swings between weekday and weekend sleep can leave you feeling off

When to See a Doctor

Long sleep on its own is not an emergency. Based on guidance from the Sleep Foundation and the NHLBI, book an appointment if:

You regularly sleep more than nine hours and are concerned, or you sleep more than 8 hours and still do not feel rested
You have excessive daytime sleepiness, fatigue or brain fog that affects work, study or daily life
You snore loudly, gasp or choke in your sleep, or someone has seen you stop breathing
Your need for sleep has risen noticeably and you cannot explain why
Long sleep comes with low mood, loss of interest, hopelessness or anxiety
The sleepiness started after a new medicine (ask your doctor or pharmacist, and do not stop a prescribed medicine on your own)

The Sleep Foundation says assessment can include a physical exam, a medical history, a medication review and sometimes a sleep study. Do not drive if you feel sleepy. If you are having thoughts of harming yourself, get urgent help from your doctor or local emergency services straight away.

FAQ

Is sleeping 10 hours a night bad for you?

An occasional 10-hour night, for example after illness, travel or a short week, is usually not a concern. Sleeping that long most nights is a pattern worth raising with a doctor, particularly if you still feel unrefreshed. Studies have linked long sleep with several health conditions, but they show associations and cannot prove that the sleep itself is the cause.

How many hours of sleep is too much?

There is no single cut-off. The Sleep Foundation defines oversleeping as more than nine hours in 24. The CDC says adults 18 to 60 need 7 or more hours, and the NHLBI suggests talking to a doctor if you regularly sleep more than 8 hours and still do not feel well rested.

Why do I sleep so much more on days off?

The NHLBI says needing much more sleep on days off can signal that you are short on sleep during the week. Extra sleep then repays some of that shortfall, although big swings between weekday and weekend sleep can upset your sleep-wake rhythm.

Does oversleeping cause health problems?

That is not established. Long sleep has been associated with conditions such as heart disease, type 2 diabetes and stroke, but most of the research is observational. An underlying condition could lead to both longer sleep and poorer health, so the studies cannot show that sleeping longer is the cause.

What should I do if I sleep a lot and still feel tired?

Keep a sleep diary for a couple of weeks and talk to a doctor. Long, unrefreshing sleep can go with sleep apnea, low mood, sedating medicines and other conditions that are worth checking. Do not stop a medicine on your own because you suspect it is making you sleepy.

Key Takeaways

An occasional long sleep is normal, and needing extra sleep on days off often reflects a weekday shortfall. Regularly sleeping more than nine hours, or more than eight and still feeling unrested, is worth discussing with a doctor, because sleep debt, sleep apnea, low mood and sedating medicines can all sit behind it. Research links long sleep with several health conditions, but it shows associations rather than causes, so use it as a prompt to look for the reason, not as a reason to worry.

About this article

Written by the Sleep Fixes editorial team. We’re not medical professionals. We research each topic against primary sources and hold ourselves to being critical and thorough about what actually makes it onto the site.

This article is part of Sleep Fixes, a site focused on practical, easy-to-follow solutions for common sleep problems like night waking, dry mouth, overheating, and disrupted sleep.

The content is based on guidance from the CDC, the NHLBI and the Sleep Foundation, and on common real-world patterns.

It is not medical advice. If your symptoms are severe, persistent, or worsening, consider consulting a qualified healthcare professional.