Why do we rub are eyes when tired

A.� Because it causes our heart rate to slow down, preparing our body for sleep. The outer eyes contain the rectus muscles, which are responsible for moving our eyeballs.

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When you rub your eyes, and apply pressure to these muscles, you also stimulate the vagus nerve that runs along side the rectus muscles. The vagus nerve has many functions, one of which is controlling heart rate.

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Q.� How much sleep do I need

A.� The amount of sleep we need varies from person to person and doesn't stay constant throughout our lifetime. Newborn babies can sleep up to 16 hours a day. On average the human adult needs around 7 to 8 hours sleep a night, although some experts think 9 hours is nearer the mark.

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Q.� What happens if I sleep for much longer than needed, will I feel really good

A.� No, in fact quite the reverse. Sleeping more than 10 hours results in difficulty waking up, taking longer to get to sleep and disturbed nights.

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Q.� How long can a person survive without sleep

A.� Sleep deprivation is a common method of torture and humans soon become disoriented if they haven't slept. Not surprisingly there isn't much in the way of data for death by lack of sleep in humans however rats deprived of sleep usually die within 2 weeks.

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Q.� What happens when I'm asleep

A.� Sleep is still not completely understood however it is essential for the rest and recovery of mind and body, it allows us to do the things we do when we're awake. Sleep come in two types: deep and light sleep. A proper nights sleep requires we get both types, recurring in 90 minutes cycles, known as the sleep cycle.

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Do you want to know why you do something Click here to ask.

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by Lisa Cardy