We all know sleeping not enough (i.e. below 7 hours) is problematic to our physical and mental health, but what about when you sleep above the optimum (i.e. above 9 hours)?
Well, i’ll save you the research and answer your questions now. It is Sleep Well Wednesdays after all.
Why do we feel exhausted when we oversleep?
It promotes circadian misalignment – a mismatch between our internal clocks and external clocks.
Essentially, as the external clock runs on a 24 hour cycle (a day length), we want to synchronise our patterns to align with this – e.g. sleep when it’s dark, wake when it’s light.
If we are sleeping beyond the regular 7-9 hours, it can throw out the delicate balance between these two clocks, and promote a similar feeling to that of jetlag – lethargy, fatigue and mental exhaustion.
What about our mood?
Similarly, up to 68% of those with bipolar are also long sleepers.
Essentially, sleep alters our delicate neurochemical balance – controlling happiness hormones such as serotonin, dopamine and norepinephrine.
Thus – as short sleep is a risk for poor mental health; so too is oversleeping.
What happens to the body?
Studies also show long sleep can be as problematic as insufficient sleep – e.g. it can increase your risk of mortality by upcto 30%. This is mainly derived from a cluster of cardiovascular illnesses linked to oversleeping, such as heart disease, diabetes and hypertension.
So, what should we aim for?
It depends on your age, sleep debt and chronotype.
Overall though, most adults need between 7-9 hours. Teens need slightly more – between 9-9.5 hours, and older adults, slightly less – between 7-8 hours.