THE SCIENCE OF SLEEP

Scientific studies have given us insights into what happens when we sleep and how the quality and quantity of sleep we get can affect us.

the sleep cycle and the chemistry of sleep and how much sleep you need

and, if you're not getting enough, how your health may be affected

The Sleep Cycle

Our sleep is complex and has several phases, all of which are believed to be important in getting a good night's sleep. Studies of people sleeping look at electrical patterns in the brain alongside eye movements and muscle activity to show two main types of sleep:

Non-rapid-eye-movement (NREM)

Sleep typically begins with NREM sleep. Here, the brain waves slow down and synchronise through several distinct phases to arrive at a stage known as "deep" or "slow-wave" sleep. While the eyes remain still, the brain becomes less responsive to external stimuli, as the sleeper becomes increasingly difficult to awaken.

Rapid-eye-movement (REM)

Next, the sleeper enters their initial REM sleep episode. Often called "active sleep", it is believed the eye movements are related to dreaming. REM sleep comprises about 20 to 25 percent of total sleep in typical healthy adults.

The two types of sleep continue to alternate through the night in a cycle, but the lengths of time of each phase or episode can vary due to many factors, such as your age and internal body clock to the amount of exercise or stress you experience.

The Chemistry of Sleep

Throughout each day and night our bodies release chemicals to help us do different things at different times in cycles known as circadian rhythms.

To help us schedule our sleep in each 24 hour period our bodies translate information about the time of day into production of a chemical called melatonin. During the day, exposure to light prevents melatonin from being produced, which keeps us awake, and at night the lack of light causes melatonin to be released, which tells us to sleep.

How Much Sleep Do I Need?

The amount of sleep people need varies across ages. A recent sleep study recommended the following for healthy individuals not suffering from a sleep disorder:

How old are you?

7-9 hours

You’re probably not getting enough sleep if you feel tired when you wake up and yearn for a nap during the day. To determine how much sleep you need, it's important to assess not only what a healthy person of your age should need but also what lifestyle factors may be affecting the quality and quantity of your sleep such as diet and stress.

7-9 hours

You’re probably not getting enough sleep if you feel tired when you wake up and yearn for a nap during the day. To determine how much sleep you need, it's important to assess not only what a healthy person of your age should need but also what lifestyle factors may be affecting the quality and quantity of your sleep such as diet and stress.

7-8 hours

You’re probably not getting enough sleep if you feel tired when you wake up and yearn for a nap during the day. To determine how much sleep you need, it's important to assess not only what a healthy person of your age should need but also what lifestyle factors may be affecting the quality and quantity of your sleep such as diet and stress.

What happens if I don't get the sleep I need?

You probably already know that not getting enough sleep makes you feel tired and find it difficult to focus on the things you need to do. The odd night without enough sleep isn't likely to harm you, but your health may be at risk if your sleep problems continue over several nights – this is known as insomnia.

As well as feeling low, insomnia may:

  • make your immune system less effective, increasing the chances of catching any bugs going ‘round
  • increase the chances of getting an injury or having an accident at home, work or on the road due to lack of concentration
  • decrease your sex drive and make it harder to conceive a baby
  • lead to depression and anxiety
  • put on weight, with a higher risk of becoming obese
  • contribute to the development of diabetes
  • increase your blood pressure which can lead to heart disease.

As many as one in three of us have problems sleeping, and stress and anxiety are often thought to be the cause.

After being kept awake due to worrying about things like work, family or health, the lack of sleep can then bring about anxieties of its own when you start to associate going to bed with being awake. By worrying about not being able to sleep you can find yourself in a vicious cycle where the problem is also the cause.

How Phenergan Night Time Works

Phenergan Night Time can help break the cycle of poor sleep.

Find out more