Why We Need Sleep
It’s vital for our brain and body to work.
There has been a gradual reduction in the amount we sleep over recent decades. This is due to a combination of factors including longer working hours, and the constant availability of shopping and entertainment.
Over the last 100 years the National Sleep Foundation data suggests the average length of sleep per night has reduced from 9 to 7.5 hours. In association with this there has been increase in people saying they feel tired.
An increase in the rates of diabetes and obesity have occurred over the same time period. Some studies in children and teenagers have suggested that short sleep length may lead to body weight problems.
How much do we need?
The amount of sleep we need varies at different stages of life. Newborns need 14-17 hours a day. This gradually reduces over time and school age children need 9-11 hours. Adults need 7-9 hours. Most of the studies define short sleep length as being less than 6.5 hours a night.
There are a whole range of issues that can result in short length or poor quality sleep:
- Lifestyle eg. drinking too much caffeine and alcohol.
- Shift work which results in exposure to light at night and not enough light during the day.
- Having a young baby
- Being a caregiver
- Being a college student
- Medical problems, like being in pain
- Anxiety and stress
- Certain sleep disorders such as Insomia, Obstructive Sleep Apnoea and Restless Leg Syndrome.
Poor sleep length and quality have wide spread effects on the body. There is elevation of various hormones including Adrenaline and Cortisol. This makes it harder for another hormone called Insulin to do it’s job of balancing blood sugar.
There are changes in the levels of appetite hormones leading to increased appetite, which results in eating more food. Finally there is increased release of substances associated with inflammation in the body.
The long-term consequences of poor sleep can therefore be important in terms of health. The increased Adrenaline levels can lead to elevated blood pressure. Eating more will lead to weight gain. Studies have also shown a higher risk of Type 2 diabetes.
Additionally, it has been found that long-term night-shift work can increase the risk of certain kinds of cancer. Being exposed to light during the night, causes a reduction in the release of the hormone Melatonin. Low levels of Melatonin mean it can’t do it’s job properly part of which is repairing abnormal cells. It’s thought that this may be part of the reason for the increased risk in cancer.
Sleeping well, for more than 6.5 hours a night is beneficial for general health in the long-term. Additionally risk of development of type 2 diabetes and weight gain is reduced. For people who already have type 2 diabetes improving sleep can improve their diabetes control.
We will look at ways we can improve sleep, and different types of specific sleep disorders in subsequent blog posts.
If you want to read more there’s a really interesting book called “Why We Sleep” by Matthew Walker
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