When you are alert, your brain generates Beta Waves. When you are awake and relaxed, these change to Alpha Waves. As you sleep, your brainwaves slow and deepen, becoming Theta and Delta Waves. Someone in a Delta Wave sleep is extremely difficult to wake up – this is what all of us call, a deep sleep.
Three to five times during the night REM (Rapid Eye Movement) sleep happens, this is the dreaming stage of your sleep. These REM stages can last between five and thirty minutes and make up about 25% of a night’s sleep. When you are not dreaming you are in Non Rapid Eye Movement sleep – or NREM.
We need both types of sleep. Sleep is vital for the well-being of our brains as well as our bodies.
- Growth hormone in children is secreted during sleep.
- Chemicals we need for our immune system are also secreted during sleep.
- Sleep gives the body a chance to repair muscles and other tissues, replace aging or dead cells, etc. (“Beauty Sleep?”)
- Sleep gives the brain a chance to organize and archive memories. Dreams are thought by some to be part of this process.
- Rats who normally live for 2-3 years, survive only 5 weeks when deprived of REM sleep.
- Rats deprived of all sleep last only about 3 weeks.
- We all know we do badly without sleep – some experts believe that this is because sleep gives neurons a chance to shut down and repair themselves. Sleep also may give the brain a chance to exercise important neuronal connections that might otherwise deteriorate from lack of activity.
John Medina – a developmental molecular biologist says though there are many mysteries about the brain, there also are some ‘brain rules’ he believes we should follow. These are well established scientific facts about our brains and the things that help it to function. One of these Brain Rules is the importance of sleep. This is what John Medina says about sleep in his book (and on his web-site) Brain Rules: (1)