While most people sleep at night, there are some who are unable to get the sleep that they need in order to function during the day. Only about 10 percent of people dream in black and white while they are sleeping. Other people who do dream at night, as not everyone does, dream in shades of colors that make it seem like a real-life movie. Cats spend about two-thirds of their lives sleeping while humans only spend about one-third of their lives in a deep slumber. A student in California holds the record for the longest length of time without sleep. The young man went 11 days without sleeping in 1964. Some people die when they try to stay awake for long periods of time like this while other people experience severe side effects associated with sleep deprivation. Sometimes, you might experience uncontrollable jerks or muscle spasms while sleeping. These are normal and indicate that the brain is trying to catch up with the fact that the body is trying to go to sleep. Hypnic jerks are quite common among many people. These jerks give a sensation that you are falling just as soon as you try to get to sleep at night.