As we sleep our minds and bodies pass through several different stages. In fact there are five different stages of sleep, cleverly named stages 1, 2, 3, 4 and REM (Rapid Eye Movement).
Sleep begins as the mind enters into stage 1, which is a very light sleep from which a person can be easily startled and awakened. The heart rate slows, movements slow, and the body temperature drops. You may have noticed on warm evenings that, when the temperature is uncomfortably warm, your body begins to cool even before you actually enter into sleep mode.
As a person progresses through stage 2, 3 and 4 sleep becomes deeper and more restful. In stages 3 and 4 it is much more difficult to be awakened. This is the time where you are receiving the best and most regenerative effects of sleeping. If awakened during this stage (say, from an alarm clock) you will usually awaken groggy and disoriented, and it may take a few minutes to shake out the cobwebs.
The final stage of sleep is called REM, or Rapid Eye Movement. It is so named because of the rapid movements the eyes make during this stage of sleep. It is during this phase that dreams are most prevalent and most vivid. Breathing and heart rate also speed up, but the body is usually completely still.
Together the five stages of sleep make up one sleep cycle, which typically lasts about 90-100 minutes. This means that you will usually go though 5-6 cycles of sleep each night.
How does this information help you to improve your sleep? There are a couple applications that you may find helpful:
- If you wake up to an alarm and you usually wake up feeling groggy, it is probably because your current sleep habits have you being woken up in stage 3 or 4. If you adjust the time when you go to sleep to a bit earlier or later you may find that waking up becomes much easier since the alarm will end up going off when you are only lightly dozing anyway.
- If you are forced to get only a few hours of sleep at night you may benefit from planning the alarm to wake you up at the beginning of the next cycle. For example, if your sleep cycles are usually around 90 minutes, you may actually do better after 4 1/2 hours of sleep than after 5 1/2 hours of sleep just because you won’t be jarred out of a deep sleep.
- You can often greatly improve the amount of rest you are getting each night by adding only a small amount of extra time to your sleep. If you normally wake up early on in stage 3, for example, you may only have to add on another 30 minutes to get all the way through stage 4 and complete another segment of deep sleep.