To begin Matt Walker's speech about the importance of sleep, he states the men who, on average, get fewer than 5 hours of sleep per night have significantly smaller testicles compared to their well-rested counterparts. This is not the only negative impact of sleep deprivation -- women who do not receive enough sleep also have issues in their reproductive health. Moreover, sleep is essential before and after to adequately learn and retain information.
Walker and his team tested this knowledge by examining the merits of "pulling an all-nighter" to study for an exam. Sleep-deprived individuals have 40% less of an ability to make new memories compared to those who had a full night of sleep. To understand why well-rested folks are more equipped to learn new things, Walker monitored sleepers and discovered bursts of energy during the night -- known as 'brain spindles' -- that act as a file transfer mechanism for your brain.
Walker connects these findings with Dementia, Alzheimers, and aging. As we grow older our quality of sleep decreases, specifically deep sleep that creates brain spindles, and this results in a lower memory retention rate and opens us up to an increased risk of Dementia and Alzheimers. He finishes by suggesting ways to improve the quality of your sleep to increase your health now and down the road.