It is well known that lack of sleep can lead to cognitive deficits such as difficulty concentrating, learning, and memorizing. A study conducted by the University of California at Berkeley found that older people who sleep poorly experience memory loss and brain disorientation. Researchers from the Sleep and Learning Laboratory at Michigan State University discovered that lack of sleep doubles the chances of not being able to complete a series of steps without losing place and triples the number of lapses in attention. Furthermore, long-term sleep deprivation has been linked to hypertension, heart attacks and strokes, obesity, diabetes, depression and anxiety, decreased brain function, memory loss, weakened immune system, lower fertility rates and more.
Scientists believe that sleep is important for the brain to organize information from short-term memory to long-term memory. Studies have shown that even one restful night's sleep can improve memory loss. However, further research is needed to understand the effects of sleep deprivation and the restorative effects of recovery sleep on brain function and memory performance. During sleep, the brain is busy processing information from the day and creating memories.
Depression, which is common in older adults, can also mimic signs of memory loss. Interestingly, in controlled laboratory polysomnography studies in developed societies, sleep times in most individuals allowed 9 h of bed time were greater than 8 h. Unfortunately, in each of the studies that examined recovery after partial loss of sleep during the week, recovery did not extend sufficiently to observe full recovery. However, none of these studies addressed the question of how much sleep is needed for optimal performance.
A recent study found that a 90-minute recovery nap restored hippocampus-dependent learning during the day of sleep deprivation, and the structural morphology of the subfields of the hippocampus predicted the success of learning restoration. In summary, both total and chronic partial sleep loss affects specific neuronal morphometry, consistent with injury, and there is a dose response to sleep loss duration for neuronal morphometric changes for the severity of SLEEP loss. The team believes that cognitive deficits caused by lack of sleep can be reversible by reducing the concentration of a specific enzyme that accumulates in the hippocampus of the brain.