As you know, we are currently in complete darkness in polar areas, including Svalbard. The sun won't rise again until mid-February.
Under the circumstances, we have found that, unless we are in hibernation (which we should go into possibly next month), sleeping in one installment over a 24-hour period (8 hours) just doesn't work. I am indeed not sure humans are meant to follow such sleeping patterns, especially in the north. If you look at wolf packs, particularly in winter, they sleep on and off throughout a 24-hour period.
So, this is what is coming naturally for us now. We sleep when we're tried, usually 2-4 hours at a time, then fuck, ski, hunt, eat, and sleep again whenever we feel like it, not looking at the time, and not relying on sun cycles (which are non existent).
We have also changed training regimen for all men, so it can be done whenever they are up at unit level, rather than on a specific schedule, and we have found it greatly help them adapt to this unusual environment.
Sleeping Patterns on 24-hour Night Cycles
