1. The body repairs itself better during sleep
It's going to be very hard for anyone to prove that the rate of hair growth is faster during sleep than during your waking hours simply because hair grows very little during any particular day.
What can be said is that when we sleep the body repairs itself and detoxes. It also makes sense that during the day when you are up and down juggling a hefty schedule and tearing muscles in the gym, hair growth will be less of a priority for your internal systems. We've all heard the old adage that kids grow when they're sleep, so why not hair?
There does not appear to be direct scientific proof for faster hair growth during sleep but this is what I can find conclusive evidence for:
2. Stress can lead to hair loss
Not sleeping enough can cause or exacerbate stress. Stress itself is linked to hair loss. 'Hair loss is nearly always the consequence of an internal disturbance' (belgraviacentre.com) e.g. stress.
If you're stressed or sleep-deprived or both your immune system is weaker and amongst all the functions your body has to deal with it's not going to prioritise your hair.
Can you believe that a study at the University of California, Berkeley has actually shown that poor sleep lowers the ability to make good food choices?
Using functional MRI scanning, subjects were asked to rate their desire for certain foods; when they were more sleep deprived they were more attracted to less nutritious food!
The mineral and vitamins present in a healthy diet are needed for hair growth. If your body is lacking in vitamins and minerals it uses them up for important functions first (e.g. liver and kidney operation) and for less important functions (e.g. hair growth) last. If there isn't enough left over: so long good hair!
Regardless of what scientists say, I know I don't feel good when I haven't slept enough, I do eat worse and I feel all round less healthy - that cannot be conducive to retaining beautiful hair.
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