Medical myths: The mystery of sleep

Despite spending around one-third of our lives in the land of nod, sleep still holds many mysteries. Scientists are chipping away at the details, but the wonder of slumber is much more complex than it appears. In this Special Feature, we dispel some common myths.

Your brain shuts down during sleep

Thankfully, our brains do not quit their day job during sleep. Important functions, such as breathing, mean our brains can never fully shut down. In fact, during rapid eye movement (REM) sleep, when most dreams occur, brain wave activity is likeTrusted Source that of wakefulness.

Interestingly, despite the high level of activity, it is hardest to wake a sleeper during REM sleep. This is why this stage of sleep is sometimes called paradoxical sleep.

While we sleep, our white and gray matter has much to do. Once we have dropped off, our brain cycles through three stages of non-REM sleep, followed by one phase of REM sleep. In each of the four stages, the brain demonstrates specific brain wave patterns and neuronal activity.

This cycle of four stages repeats five or six times during a full night’s sleep.

If you remember your dream, you slept well

Most people dream every night, yet we often don’t remember them. Dreams mostly occur during REM sleep, but they are almost immediately forgotten.

It is only when someone wakes during or just after REM sleep that the memory of a dream has not yet faded.

Some evidenceTrusted Source suggests certain neurons that are active during REM sleep might actively suppress dream memories.

These neurons produce melanin-concentrating hormone (MCH), which helps regulate sleep. MCH also inhibits the hippocampus, a key brain region for memory storage.

One study approaches this question from a different angle. The researchers recruited individuals who tend to remember their dreams most nights. They found that these people became wakeful during the night more often than people who more rarely remembered their dreams.

This suggests that people who often recall dreams might sleep less well.

In short, remembering a dream is not an indication of good sleep. It is just that you woke up at the right time to recall it.

Never wake up a sleepwalker

The common claim is that if you wake a sleepwalker, they might have a heart attack or even die. This is not true.

However, if someone wakes a sleepwalker, they can spark confusion and sometimes fear. Some sleepwalkers may act aggressively, so people need to be cautious if they wake them.

Sometimes, sleepwalkers can injure themselves as they navigate the house with their eyes closed. For this reason, the best course of action is to try and coax them back to the safety of their bed.

The United Kingdom’s National Health Service (NHS) website suggests that “the best thing to do if you see someone sleepwalking is to make sure they’re safe.”

Alcohol guarantees a good night’s sleep

Alcohol reduces the amount of time it takes to get to sleep. Someone who has drunk alcohol might also be more difficult to rouse. Because of this, people often assume that it has a beneficial impact on sleep overall. This is not the case. The quality of sleep under the influence of alcohol is poorer in comparison to sleep without alcohol.

To awake feeling refreshed, our brain must cycle through the highly orchestrated series of phases and cycles mentioned earlier. Alcohol knocks this series of repetitions out of whack.

To summarize, while alcohol does get you to sleep quicker, the sleep you have will be less refreshing.

Cheese and other foods

This is an old myth that most people in the Western world will have heard. Although well known, one only has to eat cheese before bedtime to find that it is certainly not true for everyone.

However, eating a large meal just before bed, whether it includes cheese or not, can cause indigestion or heartburn, which could interfere with sleep.

If your sleep is disturbed by an active gut, and you become more wakeful more often, you will be more likely to remember any dreams you had. As mentioned earlier, people forget dreams almost as quickly as they form — unless you wake up during a dream, you are unlikely to remember it.

And, if your gut is uncomfortable, it might increase the chances of having an unpleasant dream.

Sleep still holds many mysteries. Only through science and research can we eventually unlock more answers. However, as this article outlines, we have data to dispel many of the most entrenched myths.

For now, the best advice is to avoid late-night meals, reduce alcohol intake, and be gentle with sleepwalkers.

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