Hi everyone. Have you ever had a headache after a disturbed night sleep, or felt drowsy, or had some hangover or at least a feeling of discomfort throughout the day? These are caused by lack of adequate sleep. So what is the adequate sleeping time? No one knows. It depends on the individuals habits. Generally, sleeping pattern is divided into 5 periods- 3, 4.5, 6, 7.5 and 9 hours. These are the intervals at which the brain wakes up. The ill effects of sleep can be avoided if you get up at any of the intervals mentioned. Sleep disturbances are caused by noise, light, etc. Research says that the most deadly effect of disturbed sleep is Cancer. Cancer can be caused by depression created by lack of sleep. So, try to avoid alarm clocks and night bulbs and let your brain tell you when to wake up.