“Why We Sleep” By Mathew Walker

Sleep is very important for both physical and mental wellness of a human being than diet and exercise in the health triumvirate. Every organ in our body and every process of our brain gets optimally enhanced with sleep and it resets our brain and body health each day. According to the National sleep foundation, it is imperative to have an adequate sleep of at least 6.75 to 8 hours a day for a robust immune system and to ward off several diseases.

The Deep NREM Sleep, NREM Sleep, and REM Sleep

Deep NREM sleep influences the early night hours of slumber time. REM sleep is associated with the process of dreaming, hence it is called as dream sleep. On the other hand, the non-rapid eye movement(NREM) sleep is bifurcated into four stages, with stages 3 and 4 being the deepest(Deep NREM), as it is difficult to wake an individual from sleep when compared to stages 1 and 2. The sleep pattern is split into ninety-minute cycles, NREM sleep will dominate most of the ninety-minute cycles in the initial half of the slumber while the cycles in the early morning hours are governed by REM sleep. Both REM and NREM are focal in helping the brain decide on identifying the sweet spot between the retention of old information and the addition of new data, on which memories are fresh and salient and which memories need to be eluded. Deep NREM sleep will do the weeding out activity and REM will own the process of affixing new memories. If we sleep late, we end up losing deep NREM sleep and if we wake up early in the morning, some part of REM sleep will be lost. It is of paramount importance to have all phases NREM, deep NREM, and REM sleep intact.

How should we sleep

There are two types of sleep patterns, monophasic sleep, and biphasic sleep. In most of the developed nations, monophasic sleep is followed, people will have a continuous bout of slumber at night and it will be an average 7 hours of sleep. When it comes to biphasic sleep, people will have two phases of sleep, one is the similar seven hours of sleep as in monophasic and the other is a thirty to a sixty-minute afternoon nap. In countries that are untouched by electricity like Kenya, biphasic sleep is followed. The biphasic sleep is still followed by several siesta cultures in parts of South America and Mediterranean europe. In most of the Greek cities, there will be signboards in front of the outlets like the shop is open from 9 am to 1 pm and from 1 pm to 5 pm it closed. And it will be opened from 5 pm to 9 pm. But later after the millennium turn, there was an increasing pressure to elude this practice of siesta like a culture of biphasic sleep. The after-effects of this biphasic sleep abandonment proved to be costly made from a study, many people started developing more cardiovascular diseases.

Anthropologically, humans are good terrestrial sleepers and other primates sleep well on treetops. Humans have the privilege of REM sleep and primates don’t have it. It is the ground sleeping that instigated proliferous amount of REM sleep thus instilling creativity, emotional intelligence, strategic thinking, and social complexity.

Why should we sleep

Sleep is pivotal in identifying the sweet spots of memory and acts as a memory aid, in the retention of old information, and the storage of new information. It helps in passing information to several parts of the brain, for instance for fact-based information like a new phone number or on where we parked our car, it will be stored in a temporary storage area of our brain called the Hippocampus.

For fact-based learnings such as textbook study, it is the deep NREM sleep in the initial night hours that is much superior to the REM sleep in the late night and early morning hours. Sleep replenishment will also help in other types of memory such as the Skill memory, it is something related to activities that we acquire by doing rather by learning. For instance like to ride a bike or to learn a new musical instrument.

Vigorous sleep will make the immune system ephemeral, provides all the ammunition to combat viral infections, sickness, and to ward off other dreadful diseases such as cancer, heart attacks etc. To get increased sleep, we should have more sleep opportunity time. For instance, if we have a sleep opportunity time of 8.5 hours, we will get a tenable sleep time of at least 7 hours provided we have 1.5 hours of buffer to fall asleep and compensate for lost sleep. Sleeping more hours, like up to 9 hours is also fine and no case study proved harmful to health due to excessive sleeping as high as 9 hours.

Sleep deprivation and its ramifications

Sleep loss foists certain annihilating effects on emotional conditions, they are anxiety, depression, alzheimer’s disease, bipolar disorder, stroke, suicide, and could lead to various diseases such as cancer, heart attack, weight gain, obesity, etc. There have been several fatal accidents due to drowsy driving, one could experience some small microsleep during driving and this could lead to the accident. A microsleep could be as short as 2 to 3 seconds. When we are sleep deprived, it is as equivalent to a person at the bar who has consumed alcohol exorbitantly and still taking his car keys and say “I am fine to drive home”. Hence drowsy driving is analogous to drunk driving. Sleep loss and alzheimer’s disease are causally linked, the alzheimer’s disease occurs in aged individuals above 65 and its usually because of the amyloid deposits that get clogged up near the hippocampus. It is mainly caused due to lack of deep NREM sleep(early night hours).

Sleep loss is a vociferous factor in causing weight gain, the less we sleep the more we eat. It concerns two hormones controlling appetite, they are leptin and ghrelin and incites a strong sensation of hunger. Unhealthy sleep will lead to an unhealthy heart and adults who have a chronic sleep pattern of fewer than 6 hours a day are 200 percent more likely to have a heart attack. Deficient slumber accounts for the shunning of critical passageways to the heart and thus hinders the blood supply, causing the heart to starve for blood and increase the chances of a heart attack. Prolonged sleep deprivation is a potential contributor to type 2 diabetes. Chronic sleep loss leads to insomnia and acute sleep disorder that makes us feel tired and absent-minded. Insomnia will cripple the effective functioning of emotion generating regions such as the amygdala and the memory recollection center such as the hippocampus.

Twelve tips for falling asleep quickly

1. Stick to a regular sleep schedule, set a bedtime alarm.

2. Exercise is great, but not too late in the day.

3. Avoid caffeine, nicotine, and processed food.

4. Avoid alcoholic drinks before bed.

5. Avoid large meals and beverages at night which causes indigestion and interferes with sleep.

6. If possible, avoid medicines that disrupt your sleep.

7. Don’t take naps after 3 pm, which makes it harder to fall asleep at night.

8. Relax before bed. Reading or listening to music should be a bedtime ritual.

9. Take a hot bath before bed.

10. Dark bedroom, cool bedroom, and gadget-free bedroom.

11. Try to get natural sunlight for at least 30 mins a day.

12. Don’t lie in bed awake.