How many hours of sleep do you need in order to function properly? |

Sleep is necessary for mammals and many other animals, in order to rejuvenate their bodies. During sleep consciousness is lost or reduced and we are less responsive to external activities. Most people need at least 8 hours of sleep per day in order to function at their highest level. Not getting enough sleep can increase the risks of cancer, heart disease, obesity and diabetes.

An hour consists of sixty minutes. We measure out our days in hours; when we are having fun, an hour is short. While we are suffering, an hour is very very long. In the Middle Ages (the 5th century to the 15th century) Christian monks and artists created 'Books of Hours.' They contained prayers and psalms for each hour of the day. They were 'illuminated,' that is, their texts were illustrated in gold ink and brilliant colors. The Cloisters Museum in NYC has a wonderful collection of Books of Hours.