Why We Sleep -Mathew Walker

Abhinay gave me this book a couple of months ago to read and I wish I had read it twenty years ago. Even now I feel it could be a game changer for me. Mathew Walker has researched sleep extensively and his book gives us certain pointers on how sleep must be understood. For starters he says that those who do not get 8 hours of sleep (those who get less than 6-7 hours of sleep) are in danger of health issues like a weakened immune system, double the risk of cancer, Alzheimer's, pre-diabetic, cardiovascular disease and stroke, obesity (less sleep tends to eat more). Also the shorter you sleep, the shorter your life span he says. So much so that WHO has apparently called out a sleep epidemic in industrialised nations i.e. people suffering from lack of sleep.

On the plus side, apart from the health benefits, a good 8 hour sleep enriches your ability to learn, memorise, helps creativity, helps make logical decisions, calibrates brain circuits, helps through dreams, restores immune system and helps fight malignancy and infection.

Walker explains that we all follow the circadian rhythm of the day and night, of 24 hours, and though we may have different rhythms (day birds and night owls), we must get our eight hours of sleep. He explains how this chemical called melatonin runs after dusk and brings on sleep and then shuts off gradually towards dawn helping you wake up. Research of sleep deprived professionals such as cabin crew of airlines who fly across continents and are coping with jetlag and its effect on their circadian rhythms, had parts of their brain related to learning and memory shrunk and their short term memory was impaired.

In short our
1) 24 hour circadian rhythm of suprachiasmatic nucleus and
2) the sleep pressure that builds on due to adenosine build up -
are what decide our wakefulness and sleep cycles.

When we drink caffeine we suppress adenosine (caffeine is the second most sold commodity after oil apparently). An interesting study shared is that of a spider that made its web after being administered LSD, speed, marijuana and caffeine and guess which affected it most - caffeine! And we encourage our kids to drink caffeine.

In a normal human, after a good 8 hour sleep, adenosine is purged and the circadian rhythm begins - ready for 16 hours of wakefulness. 

To know whether you had a full nights' sleep or not check this

1) after waking up,  can you fall asleep at 10-11 am again

2) can you function optimally without caffeine before noon

Sleep Verification

The gold standard for verification of sleep includes measurement of 1) brainwave activity 2) eye movement activity 3) muscle activity.

A good sleep cycle will include NREM sleep (non rapid eye movement sleep), deep NREM sleep and REM sleep (rapid eye movement sleep). Now NREM sleep and REM sleep go through a push-pull cycle of 90 minutes during which the first half is of NREM sleep and the second half is of REM sleep. NREM weeds out unnecessary neural connections while REM strengthens those connections - which means one needs both NREM and REM sleep for greater neural efficacy. What begins in infants or babies upto 6 month as 50:50 between these two, becomes 70:30 for a five year old and 80:20 for teens and adults. NREM activity typically is more during the early part of the 8 hour sleep while REM activity is more during the latter part of the 8 hour sleep cycle - so one cannot do without both ends. If sleep is insufficient, siestas are good. Daytime naps offer significant motor skill memory. 

Why Sleep

When we sleep before learning, we get a 20% learning advantage because it helps make new memories. By sleeping less than 6 hours we shortchange the brain of this learning restoration benefit. Similarly sleeping after learning helps 'save' newly created files. The more deep NREM sleep we have the more information we remember. It was found that sleep selectively boosted words tagged to 'remember' and avoided memories tagged to 'forget'. Practice of a game or music piece followed by a night of sleep led to perfection. 

A study on sleep loss and injury showed the following corelation - - 6 hours of sleep - 7% chance, 7 hours - 60%, 8 hours - 30%, 9 hours -15%.

Walker suggests that creativity increases when you sleep.

Sleep Deprivation and its Harmful Effects

Guinness Book of World Records recognised the dangers of sleep deprivation and has stopped sleep deprivation records. As mentioned earlier a host of health problems that include Alzheimer's, anxiety, depression, bipolar disorder, suicide, stroke, cancer, diabetes, heart attack, infertility, weight loss, obesity and immune deficiency.

Sleep deprivation leads to loss of concentration. We fall into micro sleeps which cause accidents. An experiment showed that a person who had 4 hours of sleep for 6 nights had a 400% increase in micro sleep! For someone who was sleepless and had alcohol, the result was 30 times worse than a sober person.

Walker says that for those who have no option, power naps could be a solution - in the early 30 minutes - which momentarily increases concentration (but does not help with complex functions)

Sleep deprivation causes emotional instability, aggressiveness. Those who do all nighters before exams actually tend to forget what they learned soon after. But if you study and sleep after learning, it consolidates learning.

Dreams

Scientists can predict content of dreams using MRI scans

REM sleep includes emotional and mental health and boosts problem solving and creativity

REM Sleep + Dreams about trauma leads to healing

Walker cites the scientist Mendleev who cracked the elementary table after a night's sleep and Paul McCartney who dreamt of the song 'Yesterday' after sleep.

More importantly he says good sleep makes the difference between knowledge and wisdom, code cracking and problem solving

Dreaming - experience and past experience

Sleep disorders 

These include somnambulism (sleep walking), insomnia (dissatisfaction with sleep quality or quantity, difficulty falling asleep, staying asleep, early morning awakening). Insomnia would mean that one has to have these issues for at least 3 nights a week for over three months. Narcolepsy (excessive day time sleep, sleepiness, sleep paralysis or cataplexy).

Alcohol, alarms, sleeping pills are not good for sleep. Instead they say try Cognitive Behavior Therapy CBT-1 which is considered the first treatment for insomnia (not sleeping pills).

Benefits of sleep in education

Of the many benefits of sleep is the connection between sleep and education. It was found that the longer the child slept the more intellectually gifted they were. It is no secret that a tired and under slept brain is like a leaky sieve. Two disasters that were caused by human error - Chernobyl and Exxon oil spill - were the result of tired and underslept people.

12 Tips to Sleep

- Stick to a sleep schedule. Go to bed and wake up at the same time. This is most important.

- Exercise for 30 minutes but not later tan 2-3 hours before bed time

- Avoid caffeine before bed. Same with nicotine, coffee, teas, chocolate 

- Avoid alcohol before bed (heavy use robs you of REM sleep)

- Avoid large meals and beverages late at night (indigestion)

- Avoid medicines that delay or disrupt sleep

- Don't nap after 3 pm

- Relax before bed - read, listen to light music, don't use LED lighting (mobile, laptop, TV screens) because it suppresses melatonin and delays sleep

 - Let the room be dark and cool, wash your face before bed, make room gadget free, no noises, lights, get good mattresses, avoid TV, mobile in room, get a good pillow, avoid clock (for clock watchers)

- Sunlight exposure is good for sleep so get 30 minutes of sunlight exposure every day. Wake up with the sun. Experts recommend getting an hour of exposure to morning sunlight, turning down lights before bed time

- Don't lie awake in bed - if you cannot sleep get up and do something until you fall asleep

Okay, so there's this site called https://www.sleepfoundation.org/ you can check on and sleep better. 

I loved the book. For years I felt I could do with little sleep going by some accounts of busy people's lives. But Walker says clearly that it is not good at all and we perform less than our capability. I have at least two or three episodes where sleep deprivation had me very disoriented and that's a feeling I can never forget. I know I still try to push my nights and try to get up early which is clearly a bad,bad idea. I am now convinced about the benefits of an 8 hour sleep and I promise myself that for the rest of my life. I must certainly thank Abhinay for giving me this book and opening my eyes to sleep!