Sleep VII

I have been lazy and I have been putting off writing about sleep for a long time now. I blame it on very busy days and I rightfully prioritised sleep over writing at 10pm in the night. French classes got busier - i cleared level 1 - hurray! I finished hosting a gorgeous retreat in the foothills of the Himalayas with a bunch of lovey very beautiful souls and I'm back to being superbly busy with classes here in Bangalore and Level 2 of my French language classes. I'd think about picking up writing about sleep on and off and i would not find the time and energy. Only this last weekend when I fell terribly sick, unable to move out of bed even, did I realise I had been sacrificing on my sleep to read a few pages or watch a little bit of TV at night or read about India's political climate on my phone - all not ideal to do at 10:00pm in the night.

So over the last week, all I have done is sleep to heal myself and thankfully I feel a lot better now. My thoughts went back to this blog and I knew I had to pick it up again. So here we are, edition # 7 of my notes on Matthew Walker's Why Sleep Matters.

This chapter that we are speaking about today addresses how sleep affects the brain and all it's function and starts off with an interesting piece of information - the Guinness Book of World Records has stopped recognising attempts to break the sleep deprivation world record. Why? Because sleep deprivation really does inflict crazy damage to the brain and the human body - neurological, psychological, physiological. "No facet of human body is spread the crippling, noxious harm of sleep loss"

Concentration

One brain function that gets disrupted with even tiny amounts of sleep deprivation is concentration. This is proven with the fatal effects of sleep deprivation on road accidents - drowsy driving is the cause of many many many accidents world over. Matthew speaks of why (and how) drowsy- driving causes accidents:

• Falling asleep at the wheel : here the individual is very sleep deprived and is a more rare case 
• Momentary lapse in concentration (microsleep) :: this is when the individual will close one eye partially or fully - often people who are routinely getting less than 7 hours of sleep.

During a microsleep, a person becoems totally blind to the outside world - not only visually, but in all channels of perception : you ability to control motor actions -operating a steering wheel of a brake pedal will momentarily cease.

Often to prove their case scientists build experiments into their studies, and often these are complicated involving loads of steps. Matthew describes a very simple experiment that David Dinges, a sleep researcher conducted to measure concentration. You needed to press a button in response to a light that appears on a button box or computer screen within a set period of time. You response and the reaction time are both measured. So easy :)

Then they divide responders into 4 groups : one that has not slept in 72 hours, one that was allowed 4 hours of sleep each night and one that was allowed 6 and last lucky one were allowed 8 full hours of sleep.  Findings :

• Sleep deprivation of all these varied amounts caused a slowing in reaction times.
• Participants would for a brief moment stop responding altogether - entirely missed responses were attributed to microsleeps - no conscious motor response.

Differences among the group were interesting - of course the 8-hour full sleep group did exceedingly well with no impairment in their performance. Those that had no sleep for 72 hours had huge lapses in concentration, with the performance falling rapidly with each night of no sleep. The group with 4 hours of sleep was just as bad as those who had not slept for 24 hours. and those with 6 hours of sleep a night for ten days also were similar to those with no sleep for 24 hours.

Baseline Re-setting

The human body is smart. Very smart. After a period of chronic sleep deprivation (say months or years) an individual will acclimate to their impaired performance, lower alertness, and reduced energy levels. That low level exhaustion becomes their accepted norm or baseline. They forget to relate low level of energy and ill health with bad sleep (!)

Drunk Driving and Drowsy Driving

Nothing explains a case in point as an experiment, so here's another one. For this one there are two groups - one that was made to get drunk to the limit of being too drunk to legally drive (.08% blood alcohol in Australia) and the other that was sleep deprived for a single night. 

Results : after being awake for 19 hours, people who were sleep deprived were as cognitively impaired as those who were legally drunk.

Matthew shares a very sobering fact - operating on less than five hours of sleep, your risk of a car crash increases threefold. The relationship between decreasing hours of sleep and increasing mortality risk of an accident is not linear - instead it exponentially mushrooms.

So until now we were looking at drunk driving and drowsy driving as two different scenarios - what happens when we combine them? Researches have proven this combination is not additive but multiplicative - they magnified each other's harmful effects! 

However, drowsy driving causes more accidents that those caused by alcohol and drugs combined - is that not crazy?! 

Drunk drivers are often late in braking and late in making evasive manoeuvres. But when you are drowsy, you stop reacting altogether - you do not brake at all or make any attempt to avoid the accident.

The History of a "Power Nap"

The US Federal Aviation Authority put a question to a couple of researchers - if the pilots could take a short naps (40-120 minutes) within a 36 hour period, where should it be placed to avoid fatigue and attention lapses - at the start of the first evening, in the middle of the night or late the following morning?

Now landing a plane is the most dangerous part of operating one - and as Matthew calls is out, it occurs at the point where the MOST amount of sleep deprivation has occured.

David Dinges and Dr, Mark Rosekind set about answering this question of when to place the nap - they wanted to place it right at the beginning of an incoming bout of sleep deprivation, that might protect you from suffering the lapses in concentration - kinda prevention is better than cure concept. 

Studies proved that they were right - pilot suffered fewer micro-sleeps at teh end stages of the flight if the naps were taken early that prior evening VS of those same naps were taken in the middle of the nights or later than ext morning when the attack of sleep deprivation was already under way.

These were officially called power naps. 

This however DOES NOT substitute an actual 8 hour sleep, you can not replace sleep with power naps- they may momentarily increase basic concentration under conditions of sleep deprivation but they can not salvage the complex functions of the brain, including learning memory, emotional stability, complex reasoning or decision making. 

Sleepless Elite

This is what Matthew calls the few rare collection of individuals who appear to be able to survive on 6 hours of sleep and show minimum impairment. Irrespective of how much time and space they are given to sleep, they will sleep only for this short amount and no more.

This is explained in their genetics - a sub variant of a gene called BHLHE41.

He then says two things to warn people who might start believing that they have this lucky gene, that made me chuckle.

• "The number of people who can survive on 5 hours of sleep or less without any impairment, expressed as a percent of the population and rounded to a whole number, is zero" ~ Dr. Thomas Roth.
• There is but a fraction of 1% of the population who are truly resilient to the effects of chronic sleep deprivation at all levels of brain functions.   It is far more likely that you will be struck by lightening than being truly capable of surviving on insufficient sleep thanks to a rare gene.

Emotional Irrationality

Inadequate sleep plays havoc on our emotions. Again a research comes to the rescue. Participants were divided into two groups :

• Group 1 : Stayed awake all night
• Group 2: Slept normally.

Each group was shown pictures of neutral emotional content ( a basket) and emotionally negative (a snake about to strike). Researchers then compared the reaction of the brain to these varied pictures.

Before we dive in the results, a little explanation of what parts of the brain are at play in this experiment. 

Amygdala : a structure located in the left and right sides of the brain - helps in triggering strong emotions like anger, rage, and is linked to fight or flight response. 

Prefrontal Cortex: the region of the brain that sits just above the eyeballs and is most developed in humans, associated with rational, logical thought and decision-making.

For the sleep deprived individuals, there was a 60% amplification in emotional reactivity in the participants who were sleep deprived, those who slept well had a modest degree of reactivity in the amygdala, despite viewing the same images.

The amygdala and the prefrontal cortex balance each other well in normal situations - one knows control the over sensitivity of the other. Without sleep, however, the emotional gas pedal (amygdala) goes on an overdrive with the brake (prefrontal cortex) not working enough.

This is true irrespective of how you deprive an individual of sleep -in one go or chronically over a period of time. They react to the same way - in fact, they are less stable in their emotions and are given to varied mood swings - positive to neutral to negative and all the way back to positive again.

So, sleep deprivation does not only take you to dark negative places and hold it there. There is an emotional center called the striatum which deals with impulsivity and reward and bathed by the chemical dopamine. This becomes hyper sensitive to rewarding and pleasurable experiences because of the loss of rational control from the prefrontal cortex. Often leading to sensation seeking, risk taking and addiction.

Depression and extreme negative mood can (and does) often lead to suicides, especially in young adults. 

Insufficient sleep is also linked to bullying and aggression and behavioural problems in children across ages. It also is a predicts early onset of drug and alcohol use.

These are all serious concerns for parents of adolescents - exactly why sleep needs to be prioritised and parents need to value it instead of chastising it!