Why oversleeping is bad for your health

Life is busy, and it’s often our sleep that suffers – research from the Sleep Health Foundation shows over 33% of Australians are at risk of damage to their mental health and workplace burnout due to sleep deprivation (1). But a subject less discussed is the dangers of oversleeping. Sleeping too much can be harmful to your body and mind, and chronic oversleeping could leave you at long-term risk of disease and other health problems. 

Do you find yourself reaching for the snooze button more often than not? Perhaps all the time? Of course, we need sleep to stay healthy – but if you’re sleeping more than nature intended, you might find that you may be doing your body more harm than good. 

The National Sleep Health Foundation states that between 7 and 9 hours sleep is normal for healthy adults between aged between 18 and 64 years.  

How much sleep is too much? 

The Sleep Health Foundation recommends not to sleep for more than 9 hours at a time – as sleeping for over 9 hours can be harmful. 

A 2018 study published in the Journal of the American Heart Association led by Keele University in the UK found that sleeping 10 hours or more increases a person’s chances of cardiovascular disease by 30% (2). 

What are the side effects of oversleeping? 

Prolonged periods of oversleeping can come with some nasty side effects, including: 

• Weight gain: one of the side effects of sleeping too much is having difficulties in maintaining a healthy weight. Simply put – the more you sleep, the less time you’re on the move, and the fewer calories you’re able to burn throughout the day.
• Increased risk of heart disease: during sleep, our heartbeat functions at rhythms than when it does when we are awake. Oversleeping side effects include being at a higher risk of heart disease and heart conditions (1). 
• Increased risk of stroke: research has found that those who sleep more than 8 hours a night are at greater risk of stroke. 
• Diminished cognitive function: a 2011 study in the UK found that sleeping more than 7-8 hours a night prematurely ages the brain and diminishes its ability to function, including memory and reaction timing. 
• Increased risk of depression. Though a healthy 7-8 hours of sleep a night improves our mental health, oversleeping can put us at risk of depression and other mental health issues. Sleeping more hours than recommended can leave us feeling groggy and tired throughout the day, which negatively impacts a person’s state of mind, and may contribute to feelings of sadness and confusion. 
• Doubles the risk of developing dementia within 10 years: people who regularly sleep for more than nine hours a night are twice as likely to develop Alzheimer’s than those who sleep 7-8 hours. 

It’s important to maintain a sleep routine, even during holidays and long weekends. This will allow your sleep cycle to function properly – including allowing you to feel sleepy and wake up at the same time every day. 

Here are some things you can do to maintain a sleep routine, to prevent oversleeping: 

• Go to bed at the same time every night, before midnight: When a person is able to sleep for 90 minutes (the length of one entire sleep cycle) before midnight, they wake up feeling more rejuvenated and lessen the chances of fatigue. 
• Avoid excessive naps, especially after 4pm: these may make it more difficult to get to sleep before midnight. If you need an afternoon boost, try power-napping instead (that is, sleeping for 20 minutes only!) 
• Eat breakfast within 30 minutes of rising: people who eat breakfast are more likely to benefit from a sustained release of energy throughout the day. What’s more, eating breakfast boosts your metabolism. 
• Let the sunshine in: if you’re worried you’re going to oversleep, try opening your blinds a little before you go to bed, to have a little help from the sunlight when you wake up in the morning. 

A number of sleep solutions can also offer help. The A.H. Beard Nox Smart Sleep Light uses intelligent technology to help you get your sleep cycle back to normal. The Nox emits a soft yellow light in the morning, simulating a natural sunrise to rouse you gently from your slumber with changing colours. 

1. Sleep Health Foundation, 2016 https://www.sleephealthfoundation.org.au/pdfs/surveys/SleepHealthFoundation-Survey.pdf 
2. Journal of the American Heart Association, ‘Self‐Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose‐Response Meta‐Analysis’, 3 August 2018