Stages of Sleep
Every 60-100 minutes we go through a cycle of four stages of sleep:
- A drowsy, relaxed state between being awake and sleeping – breathing slows, muscles relax, heart rate drops.
- A slightly deeper sleep – you may feel awake and this means that, on many nights, you may be asleep and not know it.
- (Deep Sleep) It is very hard to wake up from Deep Sleep because this is when there is the lowest amount of activity in your body.
- (Dream Sleep) After Deep Sleep, we go to Stage 2 for a few minutes, and then enter Dream Sleep – also called REM – which, as its name suggests, is when you dream.
In a full sleep cycle, a person goes through all the stages of sleep from one to four, then back down through stages three and two, before entering dream sleep.1
The deepest stage of sleep is called “slow-wave sleep” after the slow, synchronized delta waves (seen on EEG images) that define it. Though one can awaken immediately from this state, it may take up to an hour or more to regain full alertness.2
Protect Your Sleep Patterns
Every night we face many different factors that cause sleep:
1-2 Hours / Day – Exposure to light during the day decreases the sleep latency, causes fewer nocturnal awakenings and increases day time activity and alertness.
Reduce your sleeplessness by ensuring you are getting lots of light during the day — this will increase day time activity and alertness, l;eading to fewer awakenings during the night.3
-1 to -2°F – Just before we fall asleep, our bodies begin to lose some heat to the environment, which some researchers believe actually helps to induce sleep. During sleep, our central set tempoerature is reduced by 1 to 2°F.
A constant environmental tempoerature of around 18°C (65°F) is ideal for inducing and maintaining sleep.4
Pain is widely cited as one of the most common causes of sleep disturbance, and sleeplessness.
Human studies have demonstrated that the perception of pain can be altered by sleep quality. Sleep disruption leads to higher pain and stiffness ratings in arthritis patients the following day.5
Noise greater than 40 dB frequently causes difficulty initiating sleep and greater than 50 dB often causes awakenings during the night.
Sleep disturbance is one of the most impactful effects of environmental noise, causing both immediate effects and potentially long-term effects on mental and cardiovascular health.6
Large meals should be avoided prior to sleep. In addition, large volumes of liquid should also be avoided before sleep since this may lead to excessive urination at night (nocturia).7
6. http://www.scribd.com/doc/38613568/Sleep-Medicine-a-Guide-to-Sleep-and-Its-Disorders (Page 32)