Sleep Deprivation
If you are not getting enough sleep, that will kill off brain cells and that will reduce cognitive functioning which is why if you have not gotten a lot of sleep during a time period, your concentration levels are low, your memory is poor, and you feel that you have fog in the brain. Our bodies need ideally 7 to 8 hours a night to repair and heal, and that includes the brain, but some can still do well on 6 hours a night of sleep.
