What is SLEEP?

sleep baby, courtesy of dr.cabemerah

Basic Theory of Sleep
1. Passive theory of sleep: Inactivity reticularis formation in brain stem, because of tiredness
2. Active theory of sleep: Active inhibition of brain to awake area in brain

Why do we need to SLEEP?
Sleep Physiologic Effect
1. Recovering natural balance among neuronal center (rezeroing to its brain baseline)
2. Decrease sympathetic activity, increase parasympathetic activity
a. Decrease arterial pressure
b. Decrease heart rate
c. Vasodilatation
d. Muscle relaxation
e. Basal metabolism rate decrease 10-30%
f. Increase gastrointestinal activity

Normal sleep obeys 24h circadian rhythm, the neural control of which lies in the anterior hypothalamus.

Two types of nocturnal sleeps:
1. REM (rapid eye movement) sleep, is linked to dream
2. NREM (non rapid eye movement) sleep, 80% of the sleep cycle
• Stage 1: muscle are relaxed, breathing is slowed, eyelid are closed, low voltage, mixed frequency waves replace the alpha rhythm in EEG
• Stage 2: sleep spindle, vertex sharp waves, high amplitude, sharp slow wave K complex in EEG
• Stage 3 and 4: deep sleep, high amplitude delta wave in EEG

Sleep Cycles
As one falls asleep, there is progression from an alert to a drowsy state and then into stage NREM 1 -> 2 -> 3 -> 4. After 80-90 minutes, REM sleep interrupts the cycle, with burst of rapid eye movements, stirring of the limbs, changes in blood pressure and respiration and low voltage, fast frequency waves in the EEG
If the subject is awakened at this time, he often reports dreams. After a period 5-10’ of REM sleep, NREM sleep recur. With suceeding cycles, however , the four discreet stages of NREM sleep can no longer be recognized: in the later portion of night’s sleep, the sleep consist essentially of two alternating stages – REM sleep and stage 2 (spindle – vertex wave K complex) sleep


SLEEP disorder
- Insomnia
- Hypersomnic state

Insomnia
Chronic inability to sleep at times when sleeps normally occurs
- More than 3 weeks
- Delay in falling asleep
- Frequent/ easy awakening during nite
- Early morning awakening
Two major types of insomnia
1. Primary insomnia
- Absence of any medical or psychiatric illness
- Lifelong conditions
- Complain of the effects of sleep deprivation (4-5 h)
- Sleep laboratory: inadequency of sleep, failure to progress to deeper stages, limited REM sleep, frequent arousal (often due to sleep apnea)
2. Secondary (situational) insomnia
- Related to worry and anxiety (difficulty in falling sleep), depression (early morning awakening), and the abuse of alcohol and drugs, pain or breathing difficulties
Sometimes followed by special conditions:
1. Restless legs syndrome
2. Periodic leg movements
3. Acroparesthesias of the hands eg: carpal tunnel syndrome
4. Cluster headaches
5. Night mares/night terrors
Therapy:
Primary insomnia: difficult, long term sedative – hypnotic drugs in not the answer.
Secondary insomnia: treat the underlying disease (antianxiety, antidepressant, or analgesic)

How to maximize ur SLEEP?
1. Dinner : less and earlier
2. Walk 5-15’ after dinner
3. Start slowing ur rhythm in nite
4. Avoid caffeine and alcohol at least 6 hours before sleep
5. Drink a glass of milk before sleep
6. Active more in daylight, less ur nap
7. Wake up earlier 15-30’
Reference
Guyton and Hall. Physiologic medicine 9th ed
Adam’s and Victor. Manual of neurology 7th ed
The male body. Sleep chapter p122