Falling Asleep

Sleep is a very curious phenomenon - we do it every day, but we don't know why. It might allow your body and brain time to repair themselves, flush out toxins that accumulate throughout the day or strengthen memories. Depriving yourself of sleep is taxing for your body. 

We spend one third of our lives asleep and we don't know why. 

Stages of sleep

Each night you pass through different sleep levels. Level 1 is between sleep and wakefulness. In this stage, you may twitch as muscle activity slows down. As you enter true sleep, Level 2, your heart rate and breathing becomes even. During deep sleep, Levels 3 and 4, your brain waves slow and become regular. You tend to enter bouts of REM sleep once you have passed through other sleep levels. In REM sleep, your heart rate increases and brain waves look similar to when you are awake. 

Sleep walking

Sleep walking is most likely to occur during deep sleep - but why it happens remains a mystery. You may walk around, eat or even drive a car. 

Rapid eye movement sleep (REMs)

Most dreams occur during REM sleep. If woken in this stage, you are likely to remember dreaming. Your eyes move under your lids as you dream. 

Body paralysis

During REM sleep, muscles are paralysed, so you don't act out your dreams. You can wake in this stage. During this scary experience, you are semiconscious but unable to move. 

Sleep pressure

The longer you stay awake, the larger your sleep pressure. This pressure is comprised of rising levels of chemicals such as adenosine, which causes tiredness by inhibiting neurons in the brain. More adenosine is produced if you've had an active day. 

Avoiding sleep

Many of us use caffeine to help keep us awake. It makes us more alert by blocking a chemical in the brain called adenosine, which is responsible for making us sleepy. After the effects expire, we suddenly feel very tired. 

If you don't sleep

Going without sleep for a long time causes unpleasant symptoms. When you grow tired, your brain will steadily become unresponsive to neurotransmitters (chemicals) involved in regulating happiness. This is why tired people are often moody. When you sleep, your brain resets itself, and becomes sensitive to these neurotransmitters once again. The effects of sleep deprivation become progressively worse the longer you stay awake. 

Range of effects

If you don't sleep you will suffer from a range of physical and cognitive effects such as:

• Forgetfulness
• Loss of rational thought
• Risk of illness
• Higher heart rate
• Muscle tremors

Long-term sleep deprivation can even cause hallucinations.