Why Do We Dream?

Why Do We Dream?

John Lennon famously said “You may say I’m a dreamer, but I’m not the only one" – and he was right.

Whilst researchers are still debating what the function of dreaming actually is, the scientific community agree, almost unanimously, that we all dream. We also know that our dreams are most abundant during the REM stage of sleep. However, there are still many more questions which remain unanswered.

Researchers and scientists have been investigating why we dream for years. Whilst there's not yet any conclusive evidence, there are a fair few theories.

During our waking hours, the brain has to process millions of thoughts. From minor details such as the time of the party next weekend to more serious information needed for work or exams. There is a theory which suggests that dreaming helps us to organize the information we collect in the day. The dreams help us to decide which information we need to keep and what we can throw away.

Of course, these are not just claims, this is science and so we need to see the evidence. A scientific study was carried out made up of two groups. Group One were studying for a language course whilst Group Two were not. Results showed that dream activity in Group One, those who were learning a second language, was far higher than those in Group Two.

There are two further widely proposed theories. During the day our brain needs to work hard to enable us to perform certain functions. We might be focusing hard on solving problems or concentrating on a new project at work. This involves a lot of mental function. This theory states that because our emotions are largely muted during working hours, when we rest, the brain slows down and allows us to process emotions. This results in dreaming which can be literal or symbolic.

The final theory is that dreaming does not really do anything and is basically a by-product of brain activity whilst we sleep.

3B Scientific VH409 Giant Brain ModelWhat happens to the brain when we sleep?

Switching between wakefulness and sleep is a complex matter. However to keep things simple, it is thought that the venture lateral pre-optic (VLPO) nucleus, is the area in the brain which is particularly involved in the change between the two different states, sometimes referred to as the switch. Neurons in this area help to promote sleep by inhibiting areas of the brainstem which maintain wakefulness. Likewise, the areas of the brain which are active in wakefulness, by stimulating the cerebral cortex, also work to inhibit the neurons of the VLPO.

When we fall asleep, the brain doesn't just go offline but carries on performing activity. Sleep is an integral part of our lives and energizes the body’s cells, clears waste from the brain and supports learning and memory. There are also suggestions that it can affect mood, appetite and libido. Learn a little more below.


Sleep is immensely important for learning. This is because when we are sleeping, the brain can form new memories, cement older memories and create links between the two. A lack of sleep has displayed problems in the hippocampus, which is heavily involved in the creation of memories. Students revising late at night may find a reduction in recall of up to 40% when they lack the correct amount of sleep.


When we sleep our brain becomes cleaner! Sleep is required to remove harmful toxins from brain cells. These toxins have been associated with diseases such as Parkinson’s or Alzheimers. A study illustrated that when mice sleep, the space between brain cells became enlarged, this was due to clearing out of potentially damaging molecules.

Decision Making

Did you know that when you sleep your brain is actually preparing you for action and effectively making decisions?  Another study was carried out where participants were asked to sort words into groups such as animals or objects. The group had to signify their answers by hitting a button to the left or to the right. The participants were located in a darkened room and told they were allowed to sleep. When the participants fell asleep, the researchers continued to give them words and their brains still showed signs of preparing to hit right or left.

What happens to our body when we sleep?

We have learnt a little about what goes on in the brain, but what about the rest of the body?


Our heart rate falls during sleep, reducing our blood pressure and allowing us to enjoy a restful sleep.


During sleep, the body's muscles are relaxed and this gives the body the chance to repair muscle tissue.


How many times have you woken with a dry mouth? Saliva productions is reduced during sleeping hours, hence the problem. Also, 1 in 20 adults grind their teeth whilst sleeping and it is largely recognized that this is a stress releasing mechanism.


When we sleep our throat muscles relax and our airways become narrow. This is a contributing factor to snoring

The Skin

Do you get enough beauty sleep? During the day we shed dead skin cells and during sleep we replenish them, make sure you are getting enough sleep.

Immune System

Research shows that sleep helps us to fight infectious diseases, such as colds and flu.

What happens when we don’t sleep?

Not getting enough sleep has an effect on our health in many ways. For example:

Lack Of Alertness:
Even as much as a lack of 2 hours can have an effect.

Impaired Memory:
Lack of ability to think and remember

Relationship Stress:
Tiredness causes mood swings which can cause relationship problems.

Quality Of Life
Increased Chance Of Car Accidents due to drowsiness.

What is the longest time anyone has gone without sleep? Acupuncture for Insomnia

The holder of the record for a human who has intentionally gone without sleep without using stimulants is Randy Gardner. He managed a total of 264.4 hours which is 11 days 24 hours.

What were the side effects?

It was reported that Gardner struggled with moodiness, concentration, short term memory loss, paranoia and hallucinations. He also struggled to do mental math, stating he had forgotten what he was doing.

Which diseases cause sleep disturbance?

When sleep is called for, the normal signals of wakefulness are interrupted at the thalamus, this serves as the gatekeeper to the cerebral cortex. It is the thalamus which effectively slows brain waves, a damaged thalamus seriously interferes with sleep and effectively could render sleep impossible.

Other sleep disturbances can be caused by underlying problems such as.

Breathing Problems

As discussed earlier, whilst we are sleeping our airways become tighter. This has the potential to bring on nocturnal asthma attacks where the person is woken abruptly. When this frequently happens to someone, they become scared of falling asleep.

Thyroid Disease

An overactive thyroid can cause sleep problems. It can over-stimulate the nervous system and makes it difficult to fall asleep.


This is the frequent need to urinate during the night. It is a very common problem, especially among older adults.

Heart Failure

Heart failure is when the body fails to pump the blood effectively. This can leave the person short of breath and struggling to breathe when waking in the middle of the night.


Arthritis is a very painful inflammation of the joints. Whilst the patient may find it difficult to get comfortable, they often take steroids to limit pain and these are known to have an effect on sleep patterns.

What is lucid dreaming and does it really happen?

Lucid dreaming is the term given to the state when we consciously observe and control our dreams. When we are dreaming, our brain is normally in 'shut down mode' so we might find it hard to recall details. However, with lucid dreaming, we are in an altered state of awareness where we know we are dreaming and to some degree we can control what happens!

This may seem like a strange claim to some but scientific evidence has supported the idea of lucid dreaming sine 1975.

Sleeping pills and the effect on the body?

Sleeping bills are specifically designed to put the body into a relaxed state and induce sleep. Whilst the pills are effective short term, long term use can lead to addiction, memory loss and problems with concentration.

There are other side effects of sleeping pills which include weakness, stomach pain, daytime drowsiness, difficultly with balance and unusual dreams.


Do your students or patients have trouble getting the right amount of sleep?  Have you discussed addressing lack of sleep as part of an active approach to healthy living?

Leave a Reply

Your email address will not be published. Required fields are marked *