Weinke it is scientific fact people sleep less as they age. Sleep is associated with learning in current theories. So the idea is people learn less as they age, so they need less sleep. Especially , REM sleep. Look it up, it is modern sleep psychology.If you're actually getting 8 hours of sleep you aren't an old.
Most every old I know is in the 4-6 hour...maybe 7 range...maybe also an afternoon nap thrown in on the weekends.
Supposedly the elderly sleep a lot but if my 80 something year old dad was any indication, he slept in like 3 hour blocks periodically throughout the day and would be wide awake after. I hear restive sleep is hard when you're that old.