Understanding
Sleep

What happens when we sleep?

When our sleep is good, we don't think about it too much. We simply lie down, shut our eyes and fall off to sleep. Thinking about sleep can actually stop us from sleeping. To sleep, we must leave behind our wakeful state and spend several hours in a world of dreams and (hopefully) deep relaxation. Sometimes we might remember our dreams, but more often than not, we remember nothing.

However, while we sleep many physiological changes occur. Our brain activity becomes more intense, particularly during REM sleep, the stage associated with dreaming. Our breathing may become more regular, but problems can occur when there is airway obstruction, as with sleep apnoea. We experience cardiovascular changes, and metabolic changes as hormones that control our metabolism are produced during sleep. We dream, which remains a mysterious thing to researchers who suggest dreams might have a role to play in controlling memory, and 'cleaning the brain'.

Why is healthy sleep so important?

1. Sleep promotes growth and repairs

Who hasn’t told a child that they need their sleep to help them grow? Even for adults, sleep is still a time when the body gets a chance to repair itself. When we sleep our cells produce more protein, and these molecules help the body repair itself.

2. Sleep helps prevent depression and anxiety

Serotonin is produced during sleep. People who are deficient in serotonin are more prone to depression, so getting a full night’s sleep can help this. Lack of sleep can also raise anxiety levels, as the anticipatory reactions are amplified in the brain.

3. Sleep reduces stress

Without enough sleep, we get stressed. When we are stressed, we often can’t sleep. This vicious cycle puts extra stress on our body functions, and leads to an increase in blood pressure and stress hormones. Stress hormones create inflammation in the body, which contributes to conditions like diabetes, cancer and heart disease.

4. Sleep may prevent cancer

Not getting enough sleep, or being exposed to light at night, may decrease the production of melatonin. It is thought that melatonin may suppress the growth of tumours, so insufficient sleep at night may be a contributing factor in some cancers. Also, changes in melatonin may disrupt oestrogen production in women which can be a cause of breast cancer.

5. Sleep may help weight control

Another exciting new area that researchers have been working on is the link between metabolism and sleep. Getting a good night’s sleep allows the body to maintain the right balance of hormones that control appetite. Apart from the likelihood of midnight snacking, lack of sleep causes ghrelin (the hormone that regulates hunger) levels to increase and leptin (the hormone that makes us feel full) to decrease.

6. Sleep is good for heart and cardiovascular health

Blood pressure and cholesterol conditions can be worsened by a lack of sleep, which increases your risk of heart disease and stroke. When we sleep our blood pressure drops, so missing out on this regular decrease in blood pressure by not getting enough sleep puts extra strain on our heart.

Every day, sleep researchers are discovering more about sleep and its impact on our health. Healthy sleep is essential for good health, along with good nutrition and exercise. If you think your sleep is not as good as it should be, take the time to talk to your GP about your concerns. Getting a sleep test is easy, and a good investment in your longterm health.

Sources:

http://healthysleep.med.harvard.edu/healthy/science/what/characteristics

Harrington, Carmel, The Sleep Diet, Pan Macmillan, Sydney 2012

http://longevity.about.com/od/lifelongenergy/tp/healthy_sleep.htm