Sleep Needs, Cycles, and Stages

Sleep is one of the body's most mysterious processes. The idea of sleeping well conjures up restful images of fluffy pillows, comfortable blankets, and minimal activity. However, many people find sleep elusive. And the more sleep we lose, the worse our sleep problems get. Many of us are not even aware that we are sleep deprived. But sleep deprivation is a serious problem - getting insufficient sleep can wreak havoc on your health and general well-being. Read on to improve your "sleep literacy" and help you to get the sleep you need.

Why we need sleep
Sleep helps you to restore and rejuvenate many body functions:

• Memory and learning – Sleep seems to organize memories, as well as help you to recover memories. After you learn something new, sleep may solidify the learning in your brain.
• Mood enhancement and social behaviors - The parts of the brain that control emotions, decision-making, and social interactions slow down dramatically during sleep, allowing optimal performance when awake. REM sleep seems especially important for a good mood during the day. Tired people are often cranky and easily frustrated.
• Nervous system – Some sleep experts suggest that neurons used during the day repair themselves during sleep. When we experience sleep deprivation, neurons are unable to perform effectively, and the nervous system is impaired.
• Immune system – Without adequate sleep, the immune system becomes weak, and the body becomes more vulnerable to infection and disease.
• Growth and development – Growth hormones are released during sleep, and sleep is vital to proper physical and mental development.
  

How we fall asleep
Our bodies provoke us to sleep by sending messages from our circadian clocks – our inner time-keeping, temperature-fluctuating, enzyme-controlling devices. The circadian clock works in tandem with adenosine, a neurotransmitter that “turns down” many of the bodily processes that make us feel awake. Adenosine is created as our cells create the power needed to move us though the day. As the level of adenosine builds up in our brains, we feel sleepier. Along with corresponding messages from the circadian clock, this alerts us that its time to sleep. Prior to starting the sleep cycle, we first spend a few moments in a state of “relaxed wakefulness”. Most people stay in this stage for less than ten minutes, but the time you spend in relaxed wakefulness can offer clues to how well you are sleeping. If you are falling asleep the moment your head hits the pillow, you are either a very good sleeper, or you are extremely sleep deprived.

The stages of sleep: The sleep cycle
Sleep is a periodic state of rest during which consciousness of the world is interrupted. Additionally, sleep is marked by:

• decreased movement of the skeletal muscles;
• a relaxed posture, usually lying down;
• reduced response to stimulation, such as sounds and touch;
• slowed-down metabolism; and
• complex and active brain wave patterns.

Sleep is divided into two types: REM (Rapid Eye Movement) sleep and NREM (non-REM) sleep. REM sleep is when we dream. NREM sleep is further divided into four stages. A typical night of sleep follows this pattern:

• Stage 1 (Drowsiness) - When you first fall asleep, you are in Stage 1 sleep (Drowsiness). Stage 1 lasts just five or ten minutes. Eyes move slowly under the eyelids, and muscle activity slows down. You are easily awakened during Stage 1 sleep.
• Stage 2 (Light Sleep) -Next, you go into Stage 2 sleep (Light Sleep). In Stage 2, eye movements stop, heart rate slows, and body temperature decreases.
• Stages 3 & 4 (Deep Sleep) - Then you enter Stages 3 and 4 (Deep Sleep). During stages 3 and 4, you are difficult to awaken. People who are awakened during Deep Sleep do not adjust immediately and often feel groggy and disoriented for several minutes after they wake up. Children may experience bedwetting, night terrors, or sleepwalking during Deep Sleep.
• REM sleep (Dream Sleep) - At about 70 to 90 minutes into your sleep cycle, you enter REM sleep. You usually have three to five REM episodes per night. Your eyes jerk rapidly in various directions under your eyelids, thus the name Rapid Eye Movement (REM) Sleep.
  

The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep. As the night progresses, REM sleep periods increase in length while deep sleep decreases. By morning, people spend nearly all their sleep time in stages 1, 2, and REM.

What happens during the REM sleep stage?
During REM sleep, you dream actively, but your limb muscles are immobile. Your breathing is rapid, irregular, and shallow. Your heart rate increases, your blood pressure rises, males may have penile erections, and females may have clitoral enlargement. Your brain is at least as active during REM sleep as it is when you are awake. Because your major muscles do not move during REM sleep, you will not act out your dreams. (Sleepwalking occurs during NREM sleep.) Infants spend about 50 per cent of their sleep time in REM sleep; after infancy, you spend fifteen to twenty per cent of your sleep time in REM sleep.

The importance of deep sleep and dream sleep
Each stage of sleep offers benefits to th sleeper. However, deep sleep is perhaps the most vital stage, as it is the first stage that the brain attempts to recover when we are sleep deprived. If we do not get adequate deep sleep, we experience the strongest effects of sleep deprivation.

Deep sleep allows the brain to go on a little vacation needed to restore the energy we expend during our waking hours. Blood flow decreases to the brain in this stage, and redirects itself towards the muscles, restoring physical energy. Research also shows that immune functions increase during deep sleep.

REM sleep, or dream sleep, is also very important. This stage is associated with processing emotions, retaining memories, and relieving stress. Our brains suspend logic, and we lose all self-awareness – which is why we can experience ridiculous, irrational events in our dreams and believe them to be true.

If our REM sleep is disrupted one night, our bodies don't follow the normal sleep cycle progression the next time we doze off. Instead, we often go through extended periods of REM until we "catch up" on this stage of sleep. But, if deep sleep has been lost as well, our brain attempts to catch up on this stage first – in fact, the brain will try and make up all of the deep sleep it has lost and only half of the REM sleep.

Sleep Needs
The recommendation that we need eight hours of sleep to function effectively during the day is not true for all.  Many adults can’t sleep eight hours a night, and attempts to do so leads to increased wakefulness in bed.
A rule of thumb: If you wake up feeling refreshed, and you don’t feel sleepy during the day, you are getting enough sleep. If you have an occasional night of poor sleep, you probably will need to sleep more the next night to make up for it.
The amount of sleep that you need depends on a number of factors, including your genetic make-up; the amount of exercise you get; your daily activities; your age; and the quality of your sleep.

Typical Sleep Needs:

Group	Amount of Sleep Needed
Infants	About 16 hours per day of sleep
Babies and toddlers	From 6 months to 3 years: between 10 and 14 hours per day. Young children generally get their sleep from a combination of nighttime sleep and naps.  See, especially for tips on shaping nighttime awakenings in young children
Children	Ages 3 to 6: between 10 and 12 hours of sleep Ages 6 to 9: about 10 hours of sleep Ages 9 to 12: about 9 hours of sleep
Teenagers	About 9 hours of sleep per night. Teens have trouble getting enough sleep not only because of their busy schedules, but also because they are biologically programmed to want to stay up later and sleep later in the morning, which usually doesn’t mesh with school schedules
Adults	For most adults, 7 to 8 hours a night appears to be the best amount of sleep, although some people may need as few as 5 hours or as many as 10 hours of sleep each night.
Older Adults	Current thought is that older adults need as much, if not more, sleep than middle-aged adults. Taking a midday nap may help. See Sleep & Aging for more detailed information.
Pregnant women	During pregnancy, women may need a few more hours of sleep per night.

Sleep deprivation
Sleep deprivation is a tricky thing – the more deprived of sleep we are, the more tired, frustrated and hazy we feel – making us less able to recognize the effects of the deprivation and make the necessary changes to improve it. Some of the signs of sleep deprivation include difficulty waking up in the morning, lack of concentration, falling asleep during work or class, and feelings of moodiness, irritability, depression, or anxiety. Experts say that if you are falling asleep as soon as your head hits the pillow; need an alarm clock to wake up; or feel the need for frequent naps during the day, it is very likely you are sleep deprived.

The effects of sleep deprivation can be felt both physically and mentally. These may include:

• Poor decision-making, poor judgment, increased risk-taking
• Poor performance in school, on the job, and in sports
• Impaired driving performance and more car accidents
• Increased incidence of obesity, diabetes, illness in general, high blood pressure, and heart disease
• Impaired memory, concentration, and ability to learn
• Physical impairment, poor coordination, delayed reaction time
• Anxiety, depression, and other emotional problems
• Magnification of the effects of alcohol on the body
• Exacerbation of the symptoms of ADHD, such as impulse control, irritability, and lack of concentration

Try Sheep Dash! It’s an entertaining and informative way see of you are sleep deprived.

Sleep debt

Even if you are getting some sleep every night, you may not be getting as many hours as you need. Being deprived of even just a few hours of sleep each night can create a “sleep debt”, a more serious stage of sleep deprivation. A sleep debt can range from one night’s very poor sleep to the accumulation of many days of not enough sleep.

A chronic sleep debt can have serious long-term effects, including immune system problems, metabolic changes that can lead to obesity, and hyperactivity. Many of us view sleep as an indulgence or luxury, but in fact, it is a vital key to good health, as important as exercise and eating right.

Luckily, it is possible to get your sleep debt “in the black” by making up for lost sleep and improving future sleep habits.

• To make up a short-term debt, give yourself a few extra hours of sleep every night until you’ve made up for the sleep you’ve lost. For example, if you lost 5 hours, add an extra hour every night for 5 straight days.
  
  
• To make up a long-term debt, you may need to do a little more work. Experts suggest taking a vacation where you can afford to sleep as much as you want. Do not set any alarms, and allow yourself to sleep as much as you need. You may find yourself sleeping an extreme amount at the beginning of this vacation, but by the end your body should adjust back to the normal number of hours it needs.

Sleeping Well As We Age:

HEALTHY HABITS TO REDUCE SLEEP PROBLEMS & PREVENT INSOMNIA

Age alone does not cause sleep problems. Disturbed sleep, waking up tired every day, and other symptoms of insomnia are not a normal part of aging. Instead, poor sleep habits and conditions such as untreated sleep disorders, medications, or medical problems can accumulate and compound to result in sleeplessness. This article will help you understand the causes of sleep problems and provide tips to help you sleep well.

The importance of quality sleep for seniors
No matter what your age, getting the proper amount of sleep is essential to your physical health and emotional well-being. Experts disagree about whether you need less sleep as you age, or if it is just more difficult to get the sleep you need. Either way, many seniors complain about sleep problems such as:

• a desire to go to bed earlier
• difficulty falling asleep
• frequent waking during the night, and lighter sleep
• waking up early and not feeling rested
• being tired in the daytime
• needing naps during the day

To feel your best, you need a restful night of sleep, good nutrition, and exercise. You may be surprised at how good you feel when you get enough sleep.
As we age, a good night’s sleep is especially important because it improves concentration and memory formation, allows your body to repair any cell damage that occurred during the day, and refreshes your immune system which helps to prevent disease.

Causes of sleep changes as we age
As you age, you may perceive unwelcome changes in your sleep patterns, such as more fragmented sleep (more rapid sleep cycles), a decrease in deep sleep, and more awakening between sleep cycles. These changes are in the quality of sleep, rather than in the quantity of sleep. In addition, certain hormones decrease as you get older and may alter your former sleep/wake timeframe so that you feel like going to bed earlier and waking up earlier.
If you or a senior you care for is having trouble sleeping well, consider some common causes of sleep problems in the elderly:

• Poor sleep hygiene – The most common cause of insomnia in the elderly is poor sleep habits or a poor sleep environment. Examples of poor sleep hygiene are irregular sleep hours, consumption of alcohol before bedtime, and too much daytime napping.
• Pain or medical illness – Pain can keep you from sleeping well. In addition, many common health conditions can interfere with sleep: a frequent need to urinate, arthritis, asthma, diabetes mellitus, osteoporosis, nighttime heartburn, menopause, and Alzheimer's.
• Medications – Seniors tend to take more medications than do younger people. Combinations of drugs, as well as the side-effects of individual drugs, can impair sleep or even stimulate wakefulness.
• Lack of exercise – If you are too sedentary, you may not feel sleepy. Alternatively, you may feel sleepy all of the time.
• Psychological stress or psychological disorders –Significant life changes like the death of a loved one or moving from a family home can cause stress. Anxiety or sadness can also keep you awake, and sleeplessness can, in turn, cause more anxiety or depression.
• Sleep disorders - Restless Legs Syndrome (RLS),insomnia, and sleep-disordered breathing such as snoring and sleep apnea occur more frequently in older adults.

Medications can interfere with quality sleep
If you are like older adults, you take medications for one or more ongoing conditions. You may take heart medications, diabetes medications, or something for congestion. Any of these medications may have the side-effect of keeping you awake. In addition, a combination of medications can also cause sleep trouble.
While it may be difficult to pinpoint which medication could be causing sleep problems, your doctor should be able to help. Take a list of your medications to your physician and discuss your sleep problems. The solution may be as simple as switching the time of day you take your medication; changing to another medication; or lowering the dosage.

Sleep tips for the elderly
Aging alone is unlikely to be the cause of your sleep problems. Poor sleep hygiene (your sleep habits and your sleep environment) is often the main cause of low-quality sleep, and is often responsible for sleep problems in aging people.

Fortunately, sleep hygiene is easy to improve. Start by improving your sleep habits and sleep environment; then consider the other possible causes for your sleep problems.
Following are some ideas on how to tune up your sleep hygiene.
Sleep Tips for the Elderly

• Keep a regular sleep schedule – Go to bed and wake up at the same time every day, even on weekends.
• Experiment with napping – Although napping too close to bedtime, or long naps, can interfere with nighttime sleeping, some people find that short naps early in the day improve their overall feeling of being rested.
• Expose yourself to sunlight - Get at least two hours of bright sunlight each day. Exposure to sunlight increases your body’s production of melatonin, which regulates your sleep-wake cycles.
• Separate yourself from a snoring sleep partner - If your sleep partner snores, consider ear plugs or a white-noise machine, or sleep in separate bedrooms.
• Go to bed early - Adjust your bedtime earlier, to concur with when you feel like going to bed.
• Limit smoking - Nicotine is a stimulant and can keep you awake. If you can’t quit smoking, avoid smoking within three hours of bedtime.
• Develop bedtime rituals - Create soothing bedtime rituals, such as taking a hot bath or playing calm music.
• Monitor your medications – Drugs you take for your medical conditions may be interfering with your sleep.
• Take care of your psychological health – Stress and anxiety can keep you awake.
• Limit your use of sleeping aids and sleeping pills - Some over-the-counter sleep aids and prescription sleeping pills have harmful side-effects, and most are not designed to be used long-term.
• Combine sex and sleep – Sex and physical intimacy, such as hugging and massage, can provide relaxation and the physical release that lead to restful sleep. If sex makes you feel more awake, however, don’t have sex right before you want to sleep.