1
Humans sleep and awaken in a 24-hour cycle called the circadian rhythm. After 16 hours of wakeful activity, you may feel mentally and physically "burned out." After sleeping, you usually find your brain and body are "recharged" and ready for another day of activity. Sleep is necessary survival.
WHAT IS SLEEP?
Sleep is a very complex process. Several areas of the brain are involved in the wake-sleep cycle. When you sleep, your awareness of and responsiveness to the external environment are temporarily suspended. The activity of several organs slow as you sleep. For example, your heart rate and breathing slow and your body temperature drops. Sleep involves five stages, noted as one, two, three, four and REM sleep. Your brain cycles through these stages throughout the night as you sleep; each stage of sleep involves different patterns of brain activity.
DREAMING
Dreaming occurs during the REM stage of sleep. REM refers to rapid eye movement, a characteristic of this stage of sleep. Although the function of dreams remains poorly understood, it is clear that REM sleep is necessary to feel rested and refreshed.
TIPS FOR A RESTFUL SLEEP
You'll sleep more easily if you are physically tired, so make sure you get some exercise each day. However, don't exercise right before you go to bed; many people finds this makes it difficult to fall asleep. Make sure the room temperature is comfortable. Avoid caffeinated foods and beverages, such as coffee, tea, colas and chocolate, after midday. Don't smoke or drink alcohol before bedtime. Wind down before you go to bed by listening to quiet music, doing some leisure reading or taking a warm bath or shower. Once you get into bed, calm your mind and body by meditating or slowly relaxing each group of muscles. Try relaxation and imaging techniques, such as counting sheep or imagining balloons rising one by one into the air.
INSOMNIA
The term insomnia is used to describe a multitude of sleep disturbances, including poor sleep quality, difficulty falling asleep, waking up during the night and an insufficient amount of sleep. Difficulty falling asleep is often a problem with what doctors call "sleep hygiene" -- the activities that precede and surround the act of going to sleep. Daytime napping, drinking alcohol or caffeinated beverages in the evening, or routinely using your bed for awake activities, such as reading or watching TV, can make falling asleep or staying asleep difficult.
Problems falling asleep may be the result of an underlying medical illness. In fact, disruptions of the normal sleep cycle are often early clues that disease is present and, in certain circumstances, are the only warning signs that a problem exists. Depression is an example of a medical condition that can present with sleep disturbances. Many people with depression complain of an inability to sleep or sleeping too much. New problems with sleep, loss of interest in daytime activities and changes in body weight are often warning signs of depression.
Nighttime awakening is another common sleep-related complaint that may signal an underlying medical condition. For example, men with an enlarged prostate often wake up several times each night to urinate. Hormonal problems, such as an overactive thyroid or adrenal gland, can also disrupt sleep.
APNEA
Sleep apnea is a common disorder that affects approximately 18 million Americans, according to the National Institute of Neurological Disorders and Stroke. The condition is characterized by episodic interruptions in breathing while you sleep. These episodes disrupt normal sleep cycles, causing daytime sleepiness and irritability. If your partner or a family member tells you that you snore -- especially if the snoring occurs in loud bursts -- you may have sleep apnea. Talk with your doctor, particularly if you snore and experience chronic daytime sleepiness.
