Did you know that ash trays are associated with COPD? If not, do know that there is a strong link between the two. There is even a dose-response relationships: the more ash trays someone has, the more likely they are to have COPD.
Does this mean that ash trays cause COPD? That has never been proven. In fact it is believed that it is smoking cigarettes that is the culprit and not those ash trays.
Now what does this have to do with sleep? Quite a bit it turns out.
Sleep is like the ash trays in this example. Many health issues have been associated with sleep duration, but a causal relationship has never been found. And here’s whats really important to know – it is impossible to prove that how much you sleep causes health problems and long sleep is much more strongly linked to mortality than short sleep.
Let’s look at feasibility of proving that short sleep causes Alzheimer’s disease. To prove that one thing causes another you will need a randomized study with two imposed conditions. You would need thousands of people and make half of them sleep deprived and make sure the other half slept a lot. After decades of maintaining both groups short and long sleepers respectively you could look at whether Alzheimer’s happened more in the sleep deprived or non sleep deprived group.
Needless to say – a study like this will never happen. Therefore it is not possible to prove that short sleep causes any disease or health issue.
Looking at the existing link between all cause mortality (dying early for any reason) and sleep duration you find the following – having an estimated sleep duration of more than 7 hours and less than 6 hours are linked to an increased risk. Someone who feels they sleep 8 hours has an equally increased risk as someone estimating 5 hours of sleep.
If the belief is that there is a causal relationship between sleep duration, well then we should be warned not to sleep more than 7 hours. Conveniently for an industry that wants to sell products to make you sleep more, the link between long sleep and premature death is consistently overlooked.
So why is there a link between short and long sleep and premature death?
Probably because health issues can affect how much you estimate sleeping in both directions. Having arthritis and pain can disrupt your sleep and lower your estimated sleep time. Heart failure can make you tired, spend more time in bed and increase the amount of time you feel that you sleep.
Knowing that short sleep has not been shown to cause any health issues can be really reassuring to someone with insomnia.
Because as you know, worrying less is the first step towards sleeping amazing!