Our life is regulated by various bodily rhythms. Slower rhythms work in monthly, seasonal, or biannual cycles. Faster rhythms work in shorter cycles from a few minutes to a few hours - and regulate our days and nights. Our body's rhythmic cycles are controlled by the brain, which, like those of all higher vertebrates, is subject to two alternating states: sleeping and being awake.

When we are awake, the brain receives and integrates information from both internal and external stimuli. On the other hand, when we are asleep, the brain is in a state of relative inactivity with regards to motor function and perception. In addition to providing this much needed rest for the brain, sleep also allows for dreaming, which is essential to our mental and spiritual health.

Most people spend about a third of their life sleeping. However, depending on the individual, an average night of sleep can last anywhere from 4 to 10 hours. Sleep is organized into general cycles: a night's sleep normally consists of 4 to 5 cycles, each lasting approximately 90 minutes. There are 5 stages in each cycle:

• Stages I and II: Light sleep - approximately 50% of the night
• Stages III and IV: Deep sleep - approximately 25% of the night
• Stage V: Rapid Eye Movement (REM) sleep - approximately 25% of the night. This is the stage where dreaming most often takes place.

Too many short nights of sleep can lead to weight gain, skin problems, insomnia (mostly among the elderly), and of course irritability or even long-term stress. 25-30% of the population suffers from sleep disorders, with insomnia affecting 10-15%. Additional afflictions include hypersomnia (excessive daytime sleepiness) and repetitive nightmares, which are linked to physiological and mental trauma.

A number of different factors can induce insomnia:

• Emotional shocks (e.g. mourning and feelings of abandonment),
• Stress, and psychological problems
• Physical or medical problems (e.g. coughing, pain, fever, hormonal problems, respiratory problems)
• Medication (e.g. antidepressants, drugs containing caffeine, weight-loss drugs)
• Jet lag
• Inactivity (e.g. among those who are unemployed or retired; however, as we age we need less sleep)

(Some of these problems should be resolved with the help of specialists.)

Is your sleep normal? There is actually only one reliable sign of normal sleep: waking in the morning rested and in good shape, feeling that you have slept well. You can then be sure that the 5 stages of sleep have occurred successfully. Healthy sleepers fall asleep quickly (within 8 minutes), wake up very little during the night, and generally do not remember waking up.

To overcome sleep problems, we must begin by viewing sleep as both a necessity and a pleasure. We must also learn techniques to help us better prepare for sleep. Relaxation techniques are extremely important because they allow us to lower the defenses that prevent us from falling asleep.

Here are some things you can do to improve your sleep:

• Reduce consumption of alcohol, nicotine, and beverages containing stimulants like caffeine.
• Do not eat too much before lying down; do not eat after 8:00PM.
• Do not play sports or engage in any intense physical or mental activity 2 hours before lying down.
• Find an optimal sleeping position, and make sure you have a good mattress.
• Go to sleep and wake up around the same time every day.
• Pay attention to the environment of your bedroom (e.g. noise, light, temperature).
• Keep any electronics (e.g. TV, computer) away from your bed; they can be a major factor in preventing you from falling asleep.
• Choose an alarm clock that is not too bright and that has a pleasant-sounding alarm.
• Listen to calm, harmonious music on a regular basis; this has been shown to help relieve sleep disorders.