Although we spend about a third of our lives sleeping, sleep still has many mysteries. Scientists are keen to discover more and more, but the wonder of sleep is far more complex than it looks. In this article, we will dispel some of the most common myths about sleep.
As with many aspects of human biology, there is no single approach to sleep. The amount of sleep we need varies throughout life. Overall, studies suggest healthy adults should sleep 7-9 hours a day.
There is a widely shared rumor that we can train our bodies to need less than 7 to 9 hours of sleep. Fortunately, this is a myth, as these hours of sleep are essential to the normal functioning of the entire organism.
According to experts, it is rare for anyone to need less than 6 hours of sleep to function well. People who sleep 6 hours or less each night are deprived of sleep. There are studies that state that when a person is deprived of sleep, he has no idea how private he is, manifesting even a behavior similar to an alcoholic individual, who thinks, for example, that he is in perfect condition to drive. Other important studies carried out in the last decades point out that sleep deprivation is related to an increased risk of infectious diseases and several important medical diseases, including cardiovascular, depression and cancer.
However, it is important to note that rare individuals appear to function well with less than 6.5 hours of sleep per night and there is evidence that this may be related to a rare mutation in the DEC 2 gene, which may explain the performance of the current President of the Republic, Marcelo Rebelo de Sousa.
Experts generally recommend that people avoid naps in order to ensure a good night's sleep. However, if someone has had a bad night's sleep, a nap can help recover some of the lost sleep. According to Sleep Foudation, 20 minutes is an adequate duration for a nap and will be enough for the body to recharge some energy. People who sleep much more than this can fall asleep and, once awake, may feel stunned. Taking a nap during the day is a normal in some countries. Naturally, our body tends to lose energy during the early afternoon. Thus, it may be more beneficial to take a nap at this time than to avoid sleeping until night. After all, the vast majority of mammals have polyphasic sleep, which means that they sleep for short periods throughout the day. Some studies explain that afternoon naps in people who are not sleep deprived can lead to behavioral improvements and improvements in mood, drowsiness and fatigue.
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 like 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.
While some regions of the brain fall quiet during non-REM sleep, other areas leap into action. For instance, the amygdala, most famous for its role in emotion, is active during slumber.
The thalamus is an interesting case. This part of the brain is a relay station for our senses. What we see, hear, and feel arrives first at the thalamus. From there, sensory signals are ferried to the cerebral cortex, which makes sense of the inputs.
During non-REM sleep, the thalamus is relatively quiet. However, during REM sleep, the thalamus becomes active, and sends the cerebral cortex the sights and sounds of our dreams.
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 evidence 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 of the authors of the study linked above, Thomas Kilduff, Ph.D., explains:
“Since dreams are thought to occur primarily during REM sleep, the sleep stage when the MCH cells turn on, activation of these cells may prevent the content of a dream from being stored in the hippocampus — consequently, the dream is quickly forgotten.”
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.
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.
The type of meal enjoyed before dinner could also make a difference. Dr. William Kormos, Editor in Chief of Harvard Men’s Health Watch, explains:
“[E]ating a large meal, especially a high-carbohydrate meal, could trigger night sweats because the body generates heat as it metabolizes the food.”
Again, this is likely to disrupt sleep, increase wakefulness, and therefore increase the likelihood of remembering dreams.
Why and how the cheese/nightmare myth began is unclear, but the fact that cheese boards tend to appear at the end of a large meal might offer some insight.
A related myth is that certain foods, including milk, cheese, and turkey might help induce sleep. This is because they contain an amino acid called tryptophan.
Tryptophan is necessary for the body to make serotonin, which is necessary for the manufacture of melatonin, a hormone that plays a role in sleep.
Therefore, the theory goes that foods containing tryptophan might aid sleep. The most common of these myths is that Thanksgiving turkey, with its dose of tryptophan, makes someone sleepy after lunch.
However, studies investigating tryptophan intake have not found an overwhelming effect on sleep. Additionally, the levels of this acid in a portion of cheese or turkey are not high enough to make a difference.
Content adapted by the Beesleeping from the Medical News Today website.