Sleep is part of a diurnal (daily) cycle which can be broken down into four phases (not to be confused with the stages of actual sleep):

I -   Awakening 

II -  Wakefulness

III - Pre-sleep

IV - Sleep

Problems in any of these phases can affect all the other phases.  These phases were designed for the natural 24 hr cycle of light and darkness.  Unfortunately man-made inventions such as artificial light, shift work, and living in Alaska, can cause serious problems (See Solutions below).

I -   Awakening

Ideally, a person begins to awaken with the morning light.  The light penetrates the eyes and turns off the production of melatonin, a naturally-occurring sleep-inducing chemical (produced in the brain by the pineal gland).  This light exposure is part of the "entraining" process that keeps the brain on a normal diurnal cycle.  Light also is important in maintaining proper mood.  Mood and sleep are much intertwined (another subject).

II -  Wakefulness

Wakefulness is the period of maximum alertness.  Many of us never experience this phase since we have problems in the other 3 phases, as well as boring jobs.  The awake time is best spent outdoors in natural light, with artificial light a poor alternative.  

NOTE:  There is evidence that the intermittent on/off of fluorescent fixtures and computer screens creates stress and fatigue.  A mixture of fluorescent and incandescent light - continuously on - is a better option.   The "LED" (light-emitting diode) lights are also continuously "on" and probably offer a much healthier form of indoor lighting.

III - Pre-sleep

Pre-sleep occurs naturally as the sun sets and the absence of light allows melatonin production to ramp up in the brain, leading to sleep.  (Note:  Taking melatonin supplements is not the same as the real thing, since the drug is metabolized in the gut and the liver and the amount of active melatonin finally crossing the blood-brain barrier is questionable).  Artificial light has completely sabotaged this phase, as well as working long hours and eating late dinners.  Pre-sleep involves a "winding down" of activities and initiation of bedtime rituals (brushing teeth, late-night TV show, light reading, lights off, tucking self in, etc).

IV - Sleep

Sleep occurs naturally if the other phases have occurred without interference and the mind can turn off its internal chatter.

The Modern Reality

We awaken to a shrill alarm following a fitful night of poor quality sleep.  We rush through the morning ritual to hit the gym before hypnosis sets in on the freeway commute.  We spend 8 - 12 hours stressing under artificial light.  We return home to more stress, more artificial light, and disturbing newscasts, and devour 80% of our daily calories before going to sleep(?).  

Finally, to artificially induce sleep we resort to myriad chemicals, both prescription and non-prescription, the latter being mostly anti-histamines, all of which disrupt the normal sleep architecture and leave us with residual side effects in the morning, which we cancel with stimulants, such as caffeine, or perhaps other prescription medication, which we may or may not really need.

Solutions

Attempt to re-create the natural, pre-modern lifestyle as much as possible without jeopardizing job, income, or family relationships.

Genetics also play a key role in sleep patterns, but unfortunately we cannot choose our parents.

For further suggestions please see:   "Sleep"