Despite decades of efforts, one of the greatest mysteries in biology is why sleep is restorative and, conversely, why lack of sleep impairs brain function. Sleep deprivation reduce learning, impairs performance in cognitive test, prolongs reaction time, and is a common cause of seizures. So, how the system works?
It seems that toxic by-products produced during waking time are cleared during sleeping time by an increase in neuronal interstitial space. Because of the high sensitivity of neuronal cells to their environment, it is essential that waste products of neuronal metabolism be quickly and efficiently removed from the brain interstitial space. Another important finding at this regard is that the activation of the sympathetic systems seems to reduce neuronal clearance. So, having a stressful life will affect your sleeping behaviour and in consequence your brain capacity for metabolism clearance.