Sleep is vital to our well-being, ensuring that we remain as healthy and alert as possible, mentally as well as physically.
A good night's sleep will usually restore and refresh you, but the precise reason for sleeping still remains a mystery even thought there are many theories. It may be to give us time to recharge our physical and mental batteries after a busy day. Sleep also appears to help our body cells grow and regenerate, especially at times of illness. When we sleep, we conserve energy, which means we can replenish our stores. Some also believe that sleep (in particular, dreaming) helps reinforce memories and learning.
Sleep certainly benefits both the body and mind. Sleep requirements are very individual, but research shows that people who get an average of seven to eight hours sleep a night are less prone to illnesses such as heart disease, high blood pressure and colds and flu. They also suffer less from stress, anxiety and depression. A mere two consecutive nights of disrupted sleep will lower alertness and physical strength.
Our sleep patterns change as we grow older.
A new-born baby sleeps for 16 to 18 hours in a 24-hour period. Sleep is thought to be needed for growth and development. The need for sleep them gradually reduces during childhood.
Teenagers need 7-10 hours sleep a night. They go to bed late, get up late and lie in on a weekend. Their need for sleep is due to hormonal changes brought on by the onset of puberty.
The average adult need around 7.5 hours sleep a night, though this gets smaller as people move into old age.
Sleep is essential for a healthy body and mind. If you don't have enough sleep, you may be unable to function properly.
Concentration. Although sleep means rest, parts of your brain work harder while you are asleep. REM (rapid eye movement) sleep enables you to consolidate memories, which helps with learning. When sleep is disrupted, short-term memory can fail, as well as the ability to acquire new skills.
Happier mood. Good sleep is important to keep you happy and help deal with stress. People who have too little sleep often become irritable, possibly because they are not getting enough time to recuperate from daily anxieties. In fact, chronic insomnia is a major risk factor for depression.
Immune system. Sleep helps your immune system fight off germs such as viruses and bacteria, as while you sleep, your body secretes chemicals that boost your immunity. Research has found that people produce fewer disease-fighting immune cells if they have a lack of sleep. People who are ill tend to require more sleep than usual.
Reduced stress. If you get enough sleep for your body's needs, you will be much more relaxed and your blood pressure and heart rate will be low. Lack of sleep has been linked to high blood pressure, increased risk of heart disease and stroke. Stress itself is also linked to sleep disruption.
Increased energy levels. During the day, your body burns a lot of energy, which has to be replaced by eating food. While you are asleep, your body conserves energy as your metabolism slows down, giving you more usable energy during your waking hours. There is also medical evidence showing that a lack of sleep affects your hormonal system. In particular, sleep deprivation lowers your levels of leptin, which is responsible for reducing carbohydrate cravings.
Better growth and repair. While you sleep, your skin is revitalized by the growth of new cells and protein is replaced in your brain and eyes. In the early part of the night, your body secretes human growth hormone, which controls the repair of your muscles and body cells. Doctors have found that giving children with growth hormone deficiency a dose of the human growth hormone at night is more effective than giving the dose during the day, as healing occurs mainly in sleeping hours.