Is sleeping 8 hours a night a health risk?
I was always taught that sleeping 8 hours is ideal but recent research over the last 10 years
shows that this may actually be a health risk.
Over the last 10 years there have been dozens of studies that followed millions of people over time.
They have found there is a U-shape relationship between the risk of mortality and the amount of sleep you have.
Too much sleep or too little sleep are both linked to increased risk of mortality.
The lowest amount of risk is not at 8 hours but actually at 7 hours.
Long sleepers and short sleepers have a higher mortality risk.
Its important not to be too precise with the numbers however as people are not very good at measuring
exactly how long they sleep for because, well, they're asleep.
Generally, people over estimate the amount of sleep they get.
The statistics show that people who sleep less than 6 hours a night have a 12% higher
risk of mortality than those in the 6 to 8 hour range.
and people who sleep more 8 hours or more have a 30% higher risk of mortality.
Short sleep has been shown to increase blood pressure and limit the body's ability to utilise
glucose which can drive diabetes.
It is can also lead to alterations in your metabolism and weight gain.
Short sleepers are more likely to develop cardiovascular disease, have accidents, memory
problems, moodiness, impaired thinking ability and a weakened immune system.
Essentially if you don't sleep enough you are more likely to develop a range
of health problems.
While the link from limited sleep to mortality is not as strong as the link
between smoking or physical inactivity or obesity is to mortality it
is still important to manage.
The association between lack of sleep and these issues maybe be driven by other factors
that affects your sleep AND your mortality such as high stress.
Would increasing the sleep of these high risk individuals have a positive impact on their
health?
Well probably, but experts are still a little divided on this point.
What they do agree on is that there is a link between sleeping a long time and poor health
However correlation does not equal causation.
Long sleep is often a symptom of other health issues such as depression.
The increase risk of mortality with long sleepers may not be a result of the
extra sleep but rather the sleep is probably an indication of some underlying condition
that the person may not know that they have.
It is hard to be confident because most studies focus on short sleeper
because they are funded by pharmacist companies that manufacture sleeping pills.
Shaun Youngstead from Arizona State University is one of the few people who is studying the
effects of long sleep.
He completed a small study with young people who each spend 2 hours more in bed a night
for 3 weeks.
They had increases in depressed mood, inflammation, soreness and back pain.
So, it is possible that the negative effects from long sleep is driven by extended periods
of inactivity.
So how long should we sleep?
Annually the National Sleep Foundation in the US polls a random scientific sample of
adults in the US and found that the medium amount of sleep in 7 hrs.
This aligns to the medium amount for adults globally.
The majority of adults that sleep 7 hours a night report feeling rested and energetic
Experts agree that there is something about 7 hours sleep which seems to align to what
adults naturally get AND what aligns to the lowest risk of mortality.
So less than 6 hours a night has a higher risk of mortality
More than 8 hours a night seems to be linked to mortality issues as well
Somewhere between 6 and 8 hours is the ideal amount for most adults
If your an adult that consistently spends less than 6 hours in bed a night
You run a much higher risk of many health problems
If you enjoy sleeping, spend a lot of time in bed and feel perfectly
healthy you are probably just fine.
There is no sure evidence that sleeping more than 8 hours will kill you
Keep in mind with all of these figures, they are just for adults
Babies, young children, teenagers, the elderly they require different amounts of sleep
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