Are there any studies which show the range of the length of circadian rhythms for people that are removed from actual time, (Eg no sunset/ sunrise, no clocks or other reference of time)?
For example, what proportion of people tend to have a natural 30 hour rhythm or greater?
I ask because I would like to know if it is a possible cause of insomnia, how likely insomnia is caused by this, and if this knowledge might in some way lead to solutions for insomnia