Our sleeping patterns are largely a function of our daily activity, which for most of us revolves around our and our family's work/school schedule.
There are variations such as the afternoon siesta, which is the norm in some countries, as well more polyphasic sleeping (multiple short sleeps during a 24-hour period).
In terms of health there is clinical evidence that shift workers - who are chronically at odds with their natural sleeping requirements - are at increased risk of cardiovascular disease and cancer.
However, this may not be the case for everyone as there is evidence of genetic polymorphisms associated with preference for night vs day in terms of peak cognitive performance.
'Social jetlag' is a term coined to describe the disparity between our obligations to society (e.g our employer) and the needs of our biological clock.
Clearly, modern sleeping habits are not those of our ancestors and there may be a metabolic and health price to pay in order to conform.
How can sleeping be made to be more paleo?