> As always with a lot of these: it's not saying causation.
But what they are saying is, it would be valuable if it was causative wiggles eyebrows
Last sentence of the abstract:
> Sleep regularity may be a simple, effective target for improving general health and survival.
> Sleep regularity may be a simple, effective target for improving general health and survival.
But why would it NOT be? Seems stupid for us to have evolved into beings that need our sleep to be irregular.