Slaves of the Slave System Plantation agriculture was wasteful, largely because King Cotton and his money-hungry subjects despoiled the good earth; quick profits led to excessive cultivation, or âland butchery,â which in turn caused a heavy leakage of population to the West and NW.
It means that since most adults need 8-9 hours of sleep, they will need about 1.6-1.8 hours of deep sleep to feel fully functional next day. However, the time of deep sleep is changed and that's mainly due to the change in the sleep need of different group of people. For instance: Age Group.
After one to two cycles of NREM sleep, REM is entered at about 60 to 90 minutes. The first one third of the night is mostly deep sleep (NREM stages 3 and 4). The last one half of the night is predominately stage 2 NREM and REM. In newborns, the amount of sleep is divided fairly equally between night and day.