A subset of individuals have a lifelong short sleep pattern (<6 h) without showing any apparent ill effects. They are called Natural Short-Sleepers (NSS). At least two genes have been implicated as underlying this phenotype - DEC2 and more recently ADRB1. It is believed that there may be additional genes that cause this NSS phenotype and the precise mechanism that links these genes to the mechanism that induces short sleep is not known. Clinically, however, NSS who have been studied seem to thrive despite the fact that they sleep less. They live normal lives and are highly productive (to be expected since they have more waking hours in their days). We know very well by now that sleep is critically important for health. How then do these people get by with less sleep? Is it possible that they sleep more efficiently than normals and are thus able to compress within fewer hours of sleep the restorative benefits of sleep that normally take 8 hours? Possible. At least one sleep study has reported deeper NREM sleep in people with the NSS phenotype.
Interestingly, a few days ago, I met a fellow Bangalorean who said that he sleeps only 3 hours every night and has had this pattern of sleep since his younger days. He fits the phenotype previously found common in NSS - energetic, and optimistic. He is the founder of a start-up and seemed quite alert and engaged for someone who slept only 3 hours a night. Could he be a NSS? Possible. If so, he may belong to a very rare tribe of Indians who have this phenotype. NSS'ers may constitute only 1% of the population and among NSS'ers those who sleep 3 hours or less are ultra rare. My friend had constantly been hearing from doctors about the need for him to get more sleep. When I told him about NSS'ers, he felt reassured that maybe he was not burning life's candle at both ends. He is currently in touch with the researchers who uncovered with the DEC2 and ADRB1 mutations. Maybe, he will have yet another mutation that relates to this phenotype. Finding more of the genes that cause the NSS phenotype may one day help us discover mechanisms (and therefore drugs) that can help us get by with less sleep; much less sleep. Imagine that you needed to sleep only 3 hours. In a lifespan of 80 years that is more than 100,000 waking hours added. Enough time to climb the mountains in your imagination!
Creativity is a process in which we take things we already know and re-engineer them in new ways to generate new insights - insights that can then be used to build new ideas or concepts in whatever activity we may be engaged in - whether preparing a new dish in the kitchen or designing a spaceplan e to take us to Mars.
A wide variety of characters - scientists, engineers, artists and musicians have credited dreams for some of their best insights. Think mathematician Srinivasa Ramanujan and “elliptic integrals”. Paul McCartney of The Beatles and the melody for “Yesterday”.
The uncovering of insights during sleep may be more commonplace than the above examples suggest. German psychologists showed in a study done in 1984 that insights are generated when we sleep. They had two groups of volunteers take what is known as the Number Reduction Task. The task is an implementation of 2 explicit rules on a string of numbers (the parent string) to generate a new string (the daughter string). The last digit in the daughter string was the answer to the task. Unknown to the volunteers there was a hidden rule that was a shortcut to obtaining the final answer. Both groups of volunteers were given some practice session on the NRT. One group was then retested on the NRT after a period of sleep while the other group was kept awake before the retest. The group that slept had a 3-fold higher number who discovered the hidden rule. How did sleep help to uncover insight?
During sleep we cycle through NREM (non-Rapid Eye Movement) and REM sleep. Both sleep stages are involved in the consolidation of memory. But NREM is mainly involved in replaying recently acquired memories before transfer into long term storage in the cortex (the superficial grey matter that covers the brain). During REM sleep, on the other hand (also the stage when we have vivid dreams), there is widespread activation of the cortex. This widespread activation may kindle previously stored memories. Such rekindling of older memories allows the brain to juxtapose the new memory alongside older memories to select memory pairs that have common patterns, e.g. a fresh memory of a road accident gets paired with older stored memories of accidents. Such pairing of memories related to each other by context helps the brain to abstract the gist that is common to the set of memories. Such gist abstraction may occasionally pop up new solutions to problems based on similar problems encountered in the past. This serendipitous commingling of memories may thus allow the brain to generate new insight, a crucial step in the creative process. The cognitive fluidity that occurs during REM sleep due to widespread cerebral activation may be particularly conducive for creativity.
Are people with more REM more creative? It would appear so. Narcoleptics (who have disordered sleep regulation) have more REM sleep. Despite being more tired in comparison to non-narcoleptics due to chronic sleep deprivation, narcoleptics performed 10-15 % better than their healthy non-narcoleptic counterparts on tests of creativity.
REM stage sleep has also been shown to promote creativity in a prospective study where volunteers were given a test for creativity after they had slept. Those who experienced REM sleep experienced a 40% improvement in creative performance compared to a pre-sleep session whereas those who had only NREM sleep showed no improvement.
Is there any way to increase the time we spend in REM sleep. Both physical activity and extending sleep duration can do this. Cutting down on alcohol can also promote REM sleep. Increasing the time in REM may only be a part of the picture however. In almost every case where sleep and dreams intervened to provide creative insight, the period of sleep was preceded by an awake phase of intense cogitation on the problem. The mathematical genius Srinivasa Ramnujan is famously known to have frequently entered a trance like state even when awake when he was seized of a mathematical problem. The hard work of intense cogitation provides the nurturing bed in which ideas bloom during subsequent sleep and dreams.
Another prerequisite for sleep inspired creativity is knowledge. As stated in the introduction to this piece - creativity is an act of reengineering knowledge we already have. Absent knowledge, creativity cannot happen. But knowledge can be a double edged sword. Too much received knowledge - the kind obtained from textbooks - can act as a guard rail that prevents the mind from taking those diversions into uncharted territory where true innovation can bloom. Ramanujan was self-educated. He had not sat in a mathematics class in his entire life. This allowed his mind to follow the trails that were forbidden by the canons of formal mathematics of his time.
Can we improve on our creativity? We can, if we followed the following three principles - get sufficient (but not excessive) formal training in the subject; work hard and intensively on problems when awake; get enough REM sleep by extending the duration of sleep. This is not a magic triplet that guarantees results, and everyone who follows this will not become a Ramanujan. But the implementation of these principles will certainly tip the balance in favour of you extracting the greatest amount of creativity that you are capable of. You can become a more creative version of yourself, whatever be your enterprise. And if all 7 billion humans on earth did this systematically it is possible more Ramanujan-level geniuses will emerge in the future.
References:
Sleep inspires insight. Wagner U, Gais S, Haider H, Verleger R, Born J. Nature. 2004 Jan 22;427(6972):352-5.
REM, not incubation, improves creativity by priming associative networks. Cai DJ, Mednick SA, Harrison EM, Kanady JC, Mednick SC. Proc Natl Acad Sci U S A. 2009 Jun 23;106(25):10130-4. doi: 10.1073/pnas.0900271106. Epub 2009 Jun 8.
Increased creative thinking in narcolepsy. Lacaux C, Izabelle C, Santantonio G, De Villèle L, Frain J, Lubart T, Pizza F, Plazzi G, Arnulf I, Oudiette D. Brain. 2019 May 29. pii: awz137. doi: 10.1093/brain/awz137.
The idea of learning while sleeping, or hypnopaedia (hypnos, sleep; paedia, learning), is beguilingly seductive. It is a common prejudice that time spent sleeping is unproductive. From this point of view, the conversion of idle downtime during sleep into productive uptime is welcome. Furthermore, hypnopaedia promises to remove the drudgery and effort we experience when learning while awake. No wonder, throughout the 20th-century scientists kept revisiting this topic in their research. Despite their valiant efforts, no one has succeeded in convincingly demonstrating that learning can be transferred during sleep. However, hypnopaedia has been fodder for science fiction plots – most famously Aldous Huxley’s imagination of a dystopic future society (in his book “Brave New World”) where hypnopedia is used as a tool to manipulate the population. Huxley’s take on hypnopaedia reflects popular understanding in his time of the how and what of learning while sleeping. Young children are exposed to a recording of a mantra-like repetition of constructed truths as they sleep, and thereby get indoctrinated in a belief system that categorizes people into alpha’s ( “frightfully clever”) through intermediate categories called beta’s and delta’s through to the lowest category – gamma’s ( “stupid”); great fiction but not the stuff of science.
It is well established that sleep is when information that we acquire when we are awake gets consolidated and transferred from short term storage into long term memory. Can we improve the strength of memories through an intervention during sleep? This has been shown successfully in many studies where a cue (a sound or a smell) is paired with the learning event. When the same cue is presented during subsequent deep sleep, it causes a strengthening of the memory and this can be shown in a retest for the memory. It appears that the cue reactivates the memory trace during sleep thus strengthening the circuits that encode the memory. Such a technique has been used by a team of scientists at Princeton and Northwestern University to reinforce training to remove gender- and race bias. Bias is an unconscious programmed response of the brain based on heuristics derived from past experience. This ability to strengthen the effects of prior training to remove bias during a subsequent sleep session raises the disturbing possibility that such a tool could be used by an authoritarian institution to condition the behaviour of its citizens in less desirable directions. Another, and perhaps more likely scenario is that of a marketing company adopting such a technique to seed preferences for their product in the minds of unsuspecting consumers.
As seen in the examples above the strengthening of an already established memory by triggering the memory trace during sleep (Targeted Memory Reactivation) is no longer fiction. But can we learn something entirely new during sleep? Something to which we have never had prior exposure? The answer to this is a qualified “No”. It is doubtful that in the unconscious state that is sleep, we will be in a position to learn something complex like a formula in trigonometry since that would require a level of conscious awareness that is absent during sleep. However, can something much simpler be learnt – like an association between two sensory stimuli? Experiments have now shown that this is eminently possible. Scientists in New York carried out an experiment where a sleeping baby was exposed to a puff of air to its eye paired with a sound cue. When the baby was retested when awake with just the sound cue, it closed its eyes suggesting that the baby had learnt to associate the two stimuli during sleep. The pairing of odours has also been used to help people kick the cigarette habit, by simply exposing them during sleep to the smell of cigarettes paired to an offensive odour.
The unconscious brain when we sleep is far from idle. It churns through cycles of well-orchestrated activity, some of which is meant to reactivate memories as part of the transfer to long-term storage as stated above. The ability of the subconscious to process information and extract patterns when sleeping is probably an evolutionary adaptation that has evolved to use sleep as a time to encode pattern recognition circuits in the brain. These circuits are then used when we are awake – for example, a circuit that can predict while playing a tennis game the position of a tennis ball based on its speed and direction. Such shortcuts (heuristics) encoded by the unconscious brain are extremely useful in extracting patterns from and reacting appropriately to the complex torrent of information perceived by our senses when we are awake. Otherwise, the overload of sensory information would quickly clog the system.
We may not be able to learn when we sleep, but could we use the latent computational power of the brain when we sleep? Many historical discoveries have been attributed by their discoverers to insights that came to them when they slept – Ramanujan (mathematics of Infinite Series), Mendeleyeev (Periodic table) and Kekule (Benzene ring structure) are just a few examples from the world of science. Many famous artists have also attributed their creations to inspirations that came to them during a dream. All this suggests that the unconscious brain may be capable of feats of creativity that we remain unaware of. Tapping into this, especially when we sleep, is a project for systematic exploration. It is possible that, in the future, we may all be doing our best work – as inventors and artists and problem solvers of every kind – when we sleep. We will learn pretty much as we do now, but we may create new solutions to our problems as we sleep. Until then let us remember to discard the prejudice that sleep is idle downtime and sleep well!
Posted on March 19, 2019 by swami2m
You go to a doctor with a complaint. He sends you for a test. Based on the test result he makes a diagnosis and prescribes treatment. Diabetes? Check your blood glucose. Hypertension? Check your BP. Kidney disease? Check your creatinine. But what if you are sleep deprived? Is there a test your doctor could order to measure how sleep deprived you are? No, there is not! At least, not yet.
Sleep deprivation, apart from short term effects on brain function, increases the risk of many diseases, from diabetes to dementia. And yet, we have no objective measure of sleep deprivation! The best we can do is administer a questionnaire that captures subjective measures of the effectiveness of sleep. While these questionnaires may serve a purpose, they are nowhere close to being precise enough to pinpoint where the problem lies – do we have sufficient deep sleep, is our sleep consolidated or fragmented, how many times did we wake up, how much sleep will we need to catch up on sleep we have lost, etc. Even worse, these questionnaires do not address the issue of functional consequences of sleep deprivation – for example, ‘how has our liver metabolism been affected?’ or ‘how much waste is clogging up the brain due to lack of sleep?’.
Given the powerful impact sleep has on health, physicians should make sleep a part of their discussion with patients along with diet and exercise. If they choose to have such a discussion they have to resort to asking for a detailed sleep history. Sleep quantity can be reported on by patients by maintaining a diary of when they went to bed and when they woke up. But sleep quality is a critical variable that they have no objective measure of other than the subjective feeling of freshness when they awaken. Without such actionable test results, doctors lack the context to advise on sleep and avoid the topic altogether.
Another scenario where an objective test for sleep deprivation could prove useful is in the transportation industry. Drivers who have not slept for more than 17 hours can be as impaired as someone who is legally drunk. While we have simple breathalysers that can measure blood alcohol, there is no test for sleep deprivation that police officers could use at road stops. It is therefore not surprising that sleepy drivers are a major cause of accidents.
The gold standard tool for assessing sleep is a polysomnography study that tracks multiple parameters over a sleep session. Polysomnography studies are carried out in specialised sleep laboratories and are expensive and time-consuming and therefore not suitable for daily use.
While it is desirable to have a simple blood test to measure sleep deprivation, we must remember that sleep is a complex behaviour orchestrated by an even more complex organ – the brain. It is simplistic to assume that it will yield its secrets so easily and that a simple blood test will ever provide enough information to provide an actionable diagnosis. A whole battery of tests is more likely to be required to assess sleep comprehensively.
Until we have objective tests for sleep deprivation, we have to rely on the technology available to us today. Smartwatches and fitness bands are designed to provide information on sleep by tracking movements. The algorithms that drive these devices have evolved sufficiently to make them reasonably reliable sleep trackers. Other than these gadgets the best measure of sleep we have today is how we feel when we wake up in the morning. Even if our subjective feeling does not pinpoint with precision the physiological alterations experienced during disturbed sleep it remains a reliable indicator of the overall quality of our sleep. And if in the morning our subjective feeling tells us we have not slept well, then we should consider that sufficient feedback from our body and focus on measures that will help us sleep better. The immeasurable darkness of sleep need not be a barrier between us and good sleep!
Note: “Sleep late” in the present context refers to people with the evening chronotype who go to bed late AND wake up late compared to the average person (also referred to as OWLS, in the piece below).
Social necessity, or intrinsic drivers such as chronotype, determine when we sleep and when we wake up. People with the Evening Chronotype (Owls) are those who sleep late and wake up late, whereas those with the Morning Chronotype (Larks) are those who sleep early and wake up early. While there are a few who fall into extreme Morning and Evening Chronotype, most of us are somewhere in between (Intermediate Chronotype, Hummingbirds).
The UK Biobank is a large and ongoing study that is intended to tease out the respective contributions of genes and environment (nutrition, lifestyle, exercise, medications etc.) to development of disease. The prospective analysis in this study included 433268 adults aged 38-73 in whom mortality was studied over a period of 6.5 years. Chronotype was determined to fall into 4 groups based on a questionnaire: “Definitely a ‘morning’ type, Rather more a ‘morning’ than an ‘evening’ type, Rather more an ‘evening’ type than a ‘morning’ type, Definitely an ‘evening’ type”. When chronotype was treated as an ordinal variable starting with “Definite Morning Type” and moving to “Definite Evening Type” the study confirmed previous reports showing a significant graded increase in morbidity from psychological disorders, diabetes, neurological disorders, gastrointestinal disorders and respiratory disorders from left (Morning Chronotype) to right (Evening Chronotype). There was a 10% increase in all-cause mortality for Definite Evening Types compared to Definite Morning Types.
Why do people who sleep late suffer this increased morbidity and mortality? The increase in risk has been attributed to these chronotypes consuming less healthy diets with a greater proportion of fat (why they do this is not clearly understood, but it is probably linked to a mismatch between circadian rhythm and food consumption patterns). Previous studies including this one also show an increased risk of diabetes and cardiovascular disease in persons with the Evening Chronotype. Evening Chronotype is also associated with mood and behavioural issues (e.g. a tendency towards substance abuse) that may contribute to increased mortality in this group.
What do Evening-ers do about this? If your chronotype is socially induced (i.e. due work or social engagements that stop you from sleeping early), then it should be possible for you to revert to a hummingbird chronotype simply by adjusting your activities so that you can sleep earlier (exposure to bright light in the morning and taking melatonin before sleep can also help to make this adjustment). If those choices do not work or are unavailable, then the next best thing is to adjust work hours to suit the chronotype.
The bottom line is for Owls to get some early shut-eye and start looking more like the Lark.
Posted on February 3, 2019 by swami2m
Our brain is the seat of consciousness, the organ that makes us self aware – cogito ergo sum! But in fact, of the 80-100 billion neurons in the brain, it is only a small fraction that is accessible to our conscious awareness. Much of what happens in this organ is below the surface where conscious awareness does not penetrate. We are unconscious of the brain activities that control our heart or intestines or our breathing. Likewise, we are also unconscious of the brain processes that control routine and well-learned activities like walking, riding a bicycle or driving – which is why we can perform such tasks even as our conscious mind is engaged doing something else, like speaking to someone. But what may come as a surprise is how much of an influence unconscious brain function has on things that we regard as conscious decisions like choosing a flavour of ice-cream or choosing who we will marry!
Benjamin Libet in 1983 published the paper showing that the brain impulse that controlled a finger movement occurred hundred of milliseconds before conscious awareness of the decision to move the finger set in. The will to act seemed to originate in the unconscious. In subsequent behavioural experiments, psychologists have shown that subliminal cues (for which there is no conscious awareness) can reliably influence subsequent actions. For example, when subjects entered an office, seeing the picture of a library on a wall induced them to speak more softly or when there was a faint smell of a cleaning agent in the air they cleaned their desk more often. It is becoming clear that the unconscious brain has a more significant effect on our behaviours than we realise.
Our sense organs continuously feed information in quantities that can quickly overwhelm the brain if all of it had to be consciously processed – the eyes alone feed in about 10 million bits of information per second. Evolution has ensured that information not requiring our attention gets processed at an unconscious level and the appropriate action is triggered. For this to happen the brain stores matches between incoming information and the corresponding actions – in effect the unconscious brain operates like a heuristics engine. Every now and then novel situational occurrences can disturb the equation between input and action. For example, a bike rider unexpectedly encountering oncoming traffic must know to take appropriate evasive action. How does the conscious brain take over from the unconscious brain in response to such atypical situations?
The prefrontal cortex is where executive decision making, planning, control of impulsivity etc. takes place – in some senses, it is a master regulator of actions triggered in the brain. In the awake state, the prefrontal cortex is continuously monitoring sensory inputs and triggers the conscious brain to take over from the unconscious brain when required – as in the example with the bike rider above. When we fall asleep, the prefrontal cortex becomes less active. In the absence of the monitoring/censoring role of the prefrontal cortex, the unconscious is less restrained in the directions that it can take and every now and then this release from censorship takes the form of fantastic dreams.
The unconscious brain has evolved to be extremely efficient as a heuristics engine that can quickly form associations by matching sensory inputs to actions based on prior experience. During sleep, in the absence of data pressure from sensory inputs, the heuristics engine is free to form novel associations. Is it possible then that many of the creative insights that occur during sleep are a result of the unconscious brain acting independently to form novel associations? This is a plausible hypothesis. A similar process may also account for the fact that creative insights into problems during the awake state usually happen when the conscious brain is quietened, during tasks that are less demanding, e.g. having a bath or taking a walk or sitting in the back of a taxi. Thus, William Hazlitt may have been on to something when he said – “The definition of genius is that it acts unconsciously!” Ramanajun, the Indian mathematician is famously known to have attributed his mathematical inspirations to dreams when he slept. This is the subject of a small section titled “REM and Ramanujan” in my book Mastering Sleep.
Posted on January 8, 2019 by swami2m
A good mattress is an essential ingredient to ensure good sleep, but not so much in the way we think. We associate mattresses with back comfort and it is true that your mattress can make a difference to whether you sleep comfortably or awaken with a sore back. But a subtler and more pervasive effect of mattresses on sleep has to do with the material of which the mattress is made – whether it absorbs and dissipates your body heat or if it allows the heat to accumulate under your body.
The circadian rhythm dictates the fact that when we sleep our body temperature falls by a couple of degrees. This fall in temperature is not critical just to the onset of sleep but also to ensure that the subsequent sleep is deep (and therefore refreshing). A common recommendation to get a good nights sleep is to have a hot water bath before going to bed. The subsequent cooling seems to aid the onset of sleep. If the temperature in the bedroom is kept low (around 20 degrees Celsius) then deep sleep is sustained for longer.
The material of the mattress you sleep on plays an important role in whether the heat generated by your body gets dissipated away thus allowing your body to remain cool or allows the heat to stagnate thus raising core body temperature. The mattress type that is highly recommended for people with bad backs – made of memory foam – is a heat trapper. It traps the heat under your body. This eventually raises the core body temperature during sleep. On the other hand cheaper varieties of mattresses that are made of polyester fiberfill covered with cotton fabric do an excellent job of wicking away body heat, helping maintain a low core body temperature during sleep. This phenomenon has been studied experimentally to show that the heat wicking mattresses (the springier high rebound mattress) promote deep sleep whereas the memory foam (low rebound mattress) types do not have this effect. Thus the mattress that is recommended for a bad back is often the worst type for good sleep. One way to solve this problem is to use a mattress topper made of polyester fiberfill.
If you live in the tropics where a ceiling fan is often used, the effect of a heat retaining mattress can be exaggerated since the ceiling fan cools the exposed surface of the body while the parts of the body in contact with the mattress underneath are at an uncomfortably high temperature (especially since the mattress temperature is closer to the high ambient temperature in the room). This sets up an uncomfortable gradient in body temperature that is worsened when the ceiling fan is blasted on full (a common reaction to the feeling of heat). A better solution in such a situation is to sleep on a cool surface, like a plain and thin cotton dhurry or even directly on the floor.
PLoS One. 2018 Jun 27;13(6):e0197521. doi: 10.1371/journal.pone.0197521. eCollection 2018.High rebound mattress toppers facilitate core body temperature drop and enhance deep sleep in the initial phase of nocturnal sleep.Chiba S1,2, Yagi T3, Ozone M2,4, Matsumura M2, Sekiguchi H5, Ganeko M6, Uchida S6, Nishino S2.
Posted on December 28, 2018 by swami2m
In this, the 21st century, the century of the brain, the one word that we need to pay attention to is no longer Plastics, but it could very well be Glymphatics. A network of fine vessels in the peripheral organs, including our limbs, carries that fluid that gets exuded from our blood back into the venous system and the heart. A corresponding system in the brain may be the recently discovered Glymphatics. The Glymphatic system surrounds the blood vessels that enter the brain and may be the plumbing system that drains metabolic wastes away from active brain tissue. What forces drive the flow of Glymphatic fluid in the brain – it is mainly driven by the pulsatility of the arterioles that act like a pump, driving the flow of Glymph around the small arteries in the brain. Further convective flow of Glymph through the brain tissue (the space between the nerve cells) and back into the space surrounding the veins that drain the brain is driven by respiration (the negative pressure generated in the chest during inspiration may provide a pressure sink that convectively draws Glymph from the brain into the veins). What does this have to do with Sleep?
Interestingly, it is during sleep that Glymphatic flux is at its highest. Indeed, during sleep, there is an expansion of the Glymphatic fluid volume. Since Glymph carries toxic wastes along with it out of the brain, it appears that a key function of Sleep may be to promote this clearing process that helps the brain rid itself of wastes that have accumulated during the metabolically hyperactive waking state. The state of quiescence during sleep also allows this cleaning process to be undertaken without disturbing that active mentation that is required by us when we are awake.
Age and sleep-loss decrease Glymph flux. This may account for the accumulation of wastes and the triggering of neurodegenerative changes in the brain due to the accumulated toxins. On the contrary, enhanced Sleep may serve as a protective mechanism that clears out these toxins when we sleep.
If the Glymphatics prove to be as important to brain health as data is starting to show, you may well want to give your kids the advice contained in the title to this piece. Getting good sleep may be the practical implementation of this advice.
Posted on December 4, 2018 by swami2m
Given all the books being written about sleep, it is apropos to ask ourselves if reading all this stuff is doing us any good. Are we sleeping any better? Or is the public fetishisation of sleep leaving us worrying and wide awake at night?
In this context, an article by Zoe Heller – “Why we sleep and why we often can’t” – that appears in the December 8 issue of The New Yorker is worth a read. Zoe Heller has this to say about “The Sleep Revolution”, a best selling how-to guide on sleep by Ariana Huffington:”…her proselytising leaves the misleading and slightly infuriating impression that sleep is a lifestyle choice, a free resource, available to all who care enough to make it a priority.” She goes on to point out that sleep deprivation, for many of us, is not a choice but a consequence of our circumstances. Low household income, shift work and belonging to a minority group are all associated with sleep deprivation of a kind that cannot be remedied by simply following sleep hygiene homilies like drinking chamomile tea before bed. In Zoe Heller’s words – “The tone here is reminiscent of Mrs Pardiggle, in “Bleak House,” distributing improving literature to the slum-dwelling poor. Try telling the lady at the food bank that she should tap into her resilience and sleep her way to the top.”
It is true that that patriarchal advise dished out in “how-to” books is annoying. But this does not mean that such advice is ineffective. Clearly, Ms Huffington did not intend her book for the demographic that cannot afford the luxury of chamomile tea or being early to bed. Her advice will also not work for those diagnosed with insomnia. In such cases, worrying about sleep may actually have the opposite effect. For the rest of us, however, sleep hygiene does work. Mere mindfulness about sleep can powerfully and favourably influence our sleep habits and help improve sleep. The good news is that even a small increase in sleep efficiency can cause a noticeable improvement in how we feel in the day.
Improving sleep efficiency by 5-10%, while highly desirable from a health point of view, is a relatively low bar. The question is – “can we truly master sleep?” Mastering sleep would entail everything from using sleep as a strategic tool before examinations or sports events to using sleep (with or without dreams!) to improve creativity, cognition and memory. Technology and knowledge available to us today can do all of this. Devices are being developed that can selectively promote the most restorative phase of sleep – slow wave sleep. There are also devices that can increase activity in the frontal lobe and promote lucid dreaming. Even without such devices and in almost every field of human endeavour, from sports to business to warfare, those who seek to improve their performance are using sleep extension and sleep loading as tools to improve performance.
Mastering sleep is not a distant mirage but a current reality. But the tools available today to master sleep are crude and unfinished. With these tools, we are only scratching the surface, in terms of how the sleeping brain can be a lever in improving the quality of our waking lives. As we head into an age where we will see increasing sophistication in how we manage our sleep, one thing is pretty clear – we will need to equip ourselves with a more in-depth and nuanced understanding of our brain and sleep to take advantage of these new tools. Mastering sleep is the holy grail for good health and performance. Luckily for us, we live in a century where this holy grail is eminently attainable.
Posted on November 6, 2018 by swami2m
There is emerging evidence showing that lack of sleep is associated with the accumulation of beta-amyloid in the brain. Since beta-amyloid is the protein that has been linked to the pathology in Alzheimer’s disease, it is hypothesized that a chronic lack of sleep increases predisposition to Alzheimer’s dementia. There is evidence from clinical studies, of beta-amyloid accumulation in the brain in chronic sleep deprivation that supports this hypothesis.
If lack of sleep increases predisposition to Alzheimer’s, does the converse hold true – i.e. does increased sleep reduce predisposition to Alzheimer’s. To study this possibility clinically we need a situation where test subjects chronically increase sleep duration. Narcolepsy is a disease where the sufferers have problems maintaining an awake state due to a deficiency in the arousal system in the brain. Although their sleep is not normal and is certainly disturbed at night, narcolepsy patients do sleep for more hours on average across a 24 hour period.
Two recent studies in narcoleptics give substance to the intriguing possibility that narcoleptics have a reduced susceptibility to dementia. Both studies (listed below) show reduced accumulation of beta-amyloid in the brains of narcolepsy patients. Separately, sleep extension has been shown to promote cognition even in healthy subjects.
All this leads to a testable hypothesis – “Promoting sleep extension in those at risk of Alzheimer’s disease can delay or prevent the onset of the disease”. If this is found to be true, then it will be one more among the many many reasons to get a good nights sleep. How can you find out if you are sleeping enough? You are getting good sleep if you (1) feel refreshed and rested when you wake up, and (2) do not feel sleepy during the day. You can also take an online version of the Epworth Sleepiness Score (e.g. https://qxmd.com/calculate/calculator_85/epworth-sleepiness-scale) to measure your daytime sleepiness and use this determine if your sleep is sufficient, both in duration and quality.
Promoting good quality sleep may become the latest prevention tool in our armamentarium against Alzheimer’s. Since there is no downside to getting a good night’s sleep it may be the best and easiest thing you could do to help your health!
1. Cerebrospinal Fluid Biomarkers of Neurodegeneration Are Decreased or Normal in Narcolepsy
Poul Jørgen Jennum, MD, Dr Med Sci Lars Østergaard Pedersen, PhDJustyna Maria Czarna Bahl, PhD Signe Modvig, MD, PhD Karina Fog, PhDAnja Holm, PhD Birgitte Rahbek Kornum, PhD Steen Gammeltoft, MD, Dr Med Sci
Sleep, Volume 40, Issue 1, 1 January 2017, zsw006,https://doi.org/10.1093/sleep/zsw006
2. Ann Neurol. 2018 Nov 2. doi: 10.1002/ana.25373. [Epub ahead of print]
Reduced brain amyloid burden in elderly patients with narcolepsy type 1.
Gabelle A1,2,3, Jaussent I2,3, Bouallègue FB2,4,5, Lehmann S2,6, Lopez R2,3,7, Barateau L2,3,7, Grasselli C1, Pesenti C7, de Verbizier D4, Béziat S2,3, Mariano-Goulart D2,4,5, Carlander B7, Dauvilliers Y2,3,7; ADNI and the MAPT-study group.
Posted on October 23, 2018 by swami2m
There are two mechanisms that influence sleep. One is the sleep-inducing homeostatic mechanism; it is what makes us feel sleepy, in proportion to the time we have spent awake. The homeostatic mechanism is likely a consequence of the molecular/metabolic changes in the brain that accumulate during the wake period.
The other is the alerting circadian mechanism; it operates as a function of time of day and is driven by the body’s own clock mechanism. The homeostatic drive to sleep and circadian drive to stay alert are mechanistically independent but converge functionally to produce sleep or alertness depending on which is more powerful at a given point in time.
The circadian drive probably evolved earlier during evolution – such a mechanism is seen even in the most primitive organisms, including bacteria. It is entrained to the 24-hour day-night cycle that is governed by the rotation of the earth on its axis. This entrainment allows the internal cycle to closely follow the periodicity of the 24-hour day-night cycle and thus internal metabolic processes follow a rhythm that is optimized to take advantage of solar daytime. For example, digestive and metabolic enzyme activity is timed to coincide with the time at which feeding occurs.
The homeostatic drive to sleep probably evolved much later consequent to the development of multicellularity, specifically the development of networks of neurons that were antecedents to the much more complex organ we call the brain. Neuronal networks in the brain store information acquired when awake. The bombarding of incoming information can quickly saturate and overcome these networks unless they are given some protected time when they can block incoming information and reset the networks to allow for efficient processing of incoming information in the next awake period (and at the same time allow for critical information that needs to be “remembered”, to leave “memory traces” in the network so that the information can be reused in a process of “learning”). The homeostatic drive probably evolved as a mechanism to allow these functions of sleep to take place.
Both the circadian drive to remain alert and the homeostatic drive to sleep coexist in most organisms. The two independent systems co-evolved to complement the other. The tango the two systems play may underlie one of the greatest evolutionary advantages we enjoy as a species.
As a species we enjoy the most efficient and consolidated sleep – ie. we are monophasic short-sleepers. In contrast, most apes are polyphasic – ie. they sleep through the day in multiple bursts. What makes humans monophasic sleepers? The homeostatic drive to sleep monotonically pushes us to sleep in proportion to the time we have been awake. If it had been the sole operator, we would have fallen asleep around 3 PM each day and then woken up again around 9 PM – not the most efficient way to operate, since in the darkness of the night our ancestors would have been at their least productive. This is where a tweak to the circadian rhythm kicks in. The circadian drive to stay alert peaks in the evening (when the homeostatic drive to sleep is intense). This allows us to stay awake beyond 4 PM, till about 9 PM. This evening wake zone beyond 4 PM gives us a solid 5 hours of wake time during the twilight hours. A time that would have been used by our cave-dwelling ancestors to socialize (unlike our cousins, the tree-dwelling apes, who would have been fitfully sleeping and occasionally falling off their nests from the top of trees!). Perhaps this socialization and sharing of knowledge helped kickstart us on our journey to becoming the smartest species on earth! Coincidentally, deep sleep also helps in brain development – an added bonus that would have helped our ancestors assimilate knowledge.
It may be oversimplifying things to say that sleep was the sole driver for the leap of our species into greatness. It was probably one ingredient among many that contributed to the perfect storm that resulted in the emergence of sapience.
Posted on October 19, 2018 by swami2m
The mantra of 7-8 hours of sleep is based on large population studies. Individuals vary in sleep requirement and this is a function of:
How efficient your sleep is: Deep slow wave sleep (Stages 3-4 NREM sleep) is the most restorative. Frequent interruptions to sleep – say due to obstructive sleep apnea or a noisy environment – leads to a reduction in time spent in deep sleep. You may not even be aware of the brief awakenings that interrupt your sleep. In such cases, you may wake up thinking that you have been sleeping for 7-9 hours when in actual fact you have only slept 60-70% of that time or less.
How much sleep you have had in the previous 24 hours: The more sleep deprived you are, the more sleep you will need.
Your genetic makeup: Some individuals seem to manage very well with a reduced sleep of 6 hours or less.
Other conditions you may have: If you have an infectious disease (like flu) you may find that you are sleepy and need to sleep longer. This may be explained by the production of inflammatory mediators that act as hypnogens in the brain. Any condition that disturbs sleep at night will also cause a compensatory increase in time spent in bed to compensate for reduced sleep efficiency (as seen in point 1 above).
So, given that sleep needs can vary in the same person at different times and can also vary between individuals, how do we find out how much sleep we need. Unfortunately, there is no blood test to determine this. The simplest way to determine your sleep need is to spend 5-10 days free sleeping (that is, start your sleep at the same time each day and then stay in bed as long as you need, to feel restored and fresh the next morning). Over time you will settle into a pattern that will show you how much sleep you actually need. If this is inordinately long (> than 9 hours) you should seek medical advice for possible conditions that may be preventing you from sleeping efficiently.
Posted on October 7, 2018 by swami2m
by Swami Subramaniam
From The Hindu Oct 7, 2018 (https://www.thehindu.com/opinion/open-page/death-before-dawn/article25144489.ece)
Recently, a young family travelling on a Kerala road met with a road accident. A gruesome tragedy. But this accident did not draw attention because it was horrific. It drew attention because of the people involved – the family of violinist Balabhaskar who plays the violin virtually as an extension of his arms. If not for the involvement of a celebrity the news would have barely drawn any comment. Early morning road accidents caused by sleepy drivers are so common today that hardly a day goes by without a report in the newspapers of an early morning traffic accident.
Worldwide, accidents caused by sleepy drivers have reached epidemic proportions. Of the 37,461 fatalities from motor vehicle accidents in the United States in 2016, some 20% were attributed to sleep-deprived drivers. In the absence of accurate official estimates, if we were to take a similar percentage for India there might have been 30,000 deaths on Indian roads due to sleepy drivers in 2016 alone. (This number is likely to be an underestimate since road accident deaths are under-reported in India.)
Several factors underlie the epidemic-scale rise in the number of traffic accidents. There are more vehicles on the road. Newly constructed highways create opportunities for unregulated increases in the speed of traffic. There is also a temptation to speed, given the powerful engines fitted in today’s vehicles. Capping this, you have sleepy drivers coasting along on automatic transmission and cruise control on often unlit stretches of smooth and straight highways with no seeming distractions – a recipe for drowsy drivers to nod off for the critical few seconds and lose control. Fatality rates per kilometre are the highest on our national highways, at 0.67 deaths per kilometre a year.
Traffic accidents caused by sleepy drivers quite often take place in the early morning hours, between 2 a.m. and 6 a.m. There is a physiological reason why we are the drowsiest at this time. The body’s natural circadian rhythm induces a nadir of alertness around 3 to 4 a.m. If you have been driving all night without sleep, then you are already as impaired as someone who is drunk. If you add to this the circadian nadir for alertness that kicks in around 3 a.m. you have a double whammy that can force even the most resolute driver to nod off at the wheel.
Sleepy drivers are indeed the equivalent of drunk drivers. Studies have shown that after a mere 17-19 hours of being awake, reaction time and coordination are impaired to levels comparable to someone who is legally drunk. While we have a campaign to stop drunk driving, there is not enough popular attention given to the fact that driving while drowsy is probably a more significant factor in road accidents (just by accounting for the fact that there is a higher percentage of drowsy drivers compared to drunk drivers). Sleep deprivation due to sleep disorders such as insomnia and obstructive sleep apnoea are also significant factors in the increasing occurrence of driving while sleepy. Unlike drunk driving, there is not (yet) a simple and objective test to measure how sleepy someone may be. It is left to the discretion of the driver to self-assess how sleepy he or she is and decide whether to stop and take some rest.
Taxi drivers, who are paid hourly, do not have the luxury of stopping for rest while their passengers sleep. Long and unpredictable work-hours dictated by the whims of passengers, poor nutrition while on the road, and a sedentary work lifestyle contribute to generally poor health and obesity, both of which are linked to sleep disturbances. It should, therefore, not come as a surprise that even the most experienced among drivers will helplessly nod off at the wheel every now and then, resulting in an extremely high rate of traffic accidents for taxi drivers.
Accidents caused by sleepy drivers are preventable. The most straightforward and best preventive measure is to refrain from driving when sleepy. At all costs, except in an emergency, driving through the night and into the early morning hours should be avoided. For those who do not have the choice, naps of about 20 minutes combined with caffeine can improve alertness. Such a nap and caffeine break taken every two-three hours can help maintain a desirable level of alertness.
At a policy level, the government needs to pay attention to this hidden epidemic. Similar to Section 185 of the Motor Vehicles Act that covers driving under the influence of alcohol or drugs, there is a need for legislation that, at the minimum, mandates sleep-breaks for drivers of modes of public transport, including taxis. Infrastructure and messaging/signage on public highways should promote the concept of taking periodic nap-breaks while driving.
However, the only way to comprehensively mitigate this problem is to create increased awareness of the risks of driving while sleepy.
Poor sleep also has consequences for health that goes beyond traffic accidents, and for a long time we have ignored the hazards of poor quality sleep. It is time the government orchestrated the delivery of a public health message emphasising the importance of good sleep. Since such a health intervention will not cost anything, it will provide tremendous bang for the healthcare buck.
Posted on September 28, 2018 by swami2m
Natasha, a chimpanzee who lives on an island sanctuary in Uganda, is remarkably smart. What can she do? She can spray water on people. She can throw a stick at an electrified fence to know if it is passing current. She can draw people’s attention by clapping her hands. Ingenious behaviours, by chimp standards. The media lionizes Natasha as the “genius chimp” and the “primate prodigy”. However, can she compose a musical score? Or even a simple poem? Can she write a letter or read a book? No, not even close. The cognition gap between the smartest chimp and even the average human is so vast that it seems incredible that chimps are, in fact, our closest cousins on the tree of evolution. Going back about 6 million years, humans and chimps had one common ancestor. Since then, our ancestors won the evolutionary lottery. There was a point in evolutionary history when it was still an open question whether the human branch or the chimpanzee branch would evolve to dominate the planet. The human branch of the tree was barely distinguishable from the ancestors of chimps. However, some half a million years ago, something happened that triggered the seeming miracle of evolution that resulted in us – Homo Sapiens (Sapiens is derived from the Latin word “sapere” which means – to be wise). From sharing a common ancestor, we have reached a stage where the story of chimps as smart as humans is improbable enough to qualify as the plot for a Hollywood production. So, what accidents brought us here?
Given where we have reached in our development as a species, it is easy to imagine that there was some evolutionary big-bang event that launched us on this trajectory. However, evidence points more towards a series of small steps for the human branch. More like an evolutionary crawl, if you may, away from the chimp branch of the tree. Even as recently as a few million years ago, there were remarkably few anatomical specializations that would have portended greatness for the human branch. Cranial capacity was comparable. If bipedality is an advantage, the chimp branch could handle that as well.
Between one and half-a-million years ago, a series of small evolutionary steps led to a tipping point after which the florid expansion of humanoid capability and capacity took place. This was a period during which the humanoid brain expanded fourfold in volume—from about 350 cc to 1350 cc. Growth in brain capacity may have, in a virtuous and never-ending cycle of use and adaptation, expanded our capabilities, which today include the ability to create synthetic computing machines far exceeding the human brain in capacity and capability. Despite billions of years of life on planet earth, it is interesting that the evolution of a species as sapient as us has happened only once. No other species has followed our evolutionary path. What role might sleep have played in this development?
It is very well established that accuracy on a psychomotor vigilance task (PVT) deteriorates with increasing time spent awake (the PVT is administered as a boring task requiring the test taker to respond to a randomly occurring light on a screen). The PVT is a very sensitive measure of cognitive deterioration that occurs with increasing sleep deprivation. In a group of healthy volunteers who were sleep deprived for 40 hours, there was the expected deterioration in PVT. But surprisingly performance on more complex cognitive tasks that tested complex attention and working memory were unimpaired by the sleep deprivation. Several messages can be derived from this study:
Simpler tasks with less cognitive load are the first affected by sleep deprivation
More complex tasks are unaffected after 40 hours of sleep deprivation (although prolonged sleep deprivation will affect these tasks as well)
This may explain why a surgeon who is sleep deprived is relatively unaffected and performs the surgery safely but a driver on a dark highway driving an automatic car with nothing to distract his attention is likely to be in more danger of an accident.
The lesson is: Making even simple tasks more complex will act as a buttress against sleepiness induced deterioration in performance. This may be why drivers in Indian cities where traffic intrusions are unpredictable suffer fewer accidents compared to the same drivers on some of the newly constructed freeways in India.
The wake maintenance zone shows task dependent changes in cognitive function following one night without sleep; William R McMahon Suzanne Ftouni Sean P A Drummond Paul MaruffSteven W Lockley Shantha M W Rajaratnam Clare Anderson; Sleep, zsy148, https://doi.org/10.1093/sleep/zsy148
As men grow older levels of the male sex hormone testosterone fall. Falling testosterone levels are associated with a reduction in muscle and bone mass and an increase in fat deposition in the trunk. As a result, testosterone replacement therapy is recommended, at least in instances where testosterone levels fall well below the normal range.
An analysis of data collected in 2011-2012 as part of the National Health and Nutrition Examination Survey (NHANES) showed a correlation between reduction in sleep duration and testosterone levels – for each hour of reduction in sleep time, testosterone levels fell by 5.85 ng/dl. Whether an intervention that increases sleep duration will reverse the fall in testosterone levels is still an open question. If causation can be proven between sleep duration reduction and testosterone level reduction it will be just another reason among the many for men to get 7 hours or more of sleep each night!
Citation: Patel P, Shiff B, Kohn TP, Ramasamy R; Impaired sleep is associated with low testosterone in US adult males: results from the National Health and Nutrition Examination Survey. World J Urol. 2018 Sep 17. doi: 10.1007/s00345-018-2485-2.
I woke up one morning this week feeling terrific. I was quickly out of bed and on my feet moving like a whirling Dervish with cleaning implements in hand. I cleaned, swabbed, dusted, mopped and washed – all in a blur of motion. My wife archly raised an eyebrow as if to ask – what has come over you?
Ever so often these days I enjoy sleep that is so restful that I feel transformed. On such occasions, my fitness band informs me that I had more deep sleep than usual (deep sleep is when the restorative benefits of sleep are obtained). Long, uninterrupted episodes of deep sleep leave me feeling supercharged the next morning. Since I would like to feel this way every day (who wouldn’t?) I pay careful attention to the various influences in my life that give me a leg up towards the objective of getting deep restful sleep.
I should be a master at sleeping. After all, I have written a book with the title - “Mastering Sleep”. To write the book I waded chest-deep through the scientific literature on sleep science – I count having perused more than 1500 papers over 18 months of intense research. What I found is that sleep is influenced by a long list of things — your genes, what you eat, how much caffeine or alcohol you imbibe, how much you worry, exercise, other diseases you may have, your mattress, the temperature of the bedroom, your blankets, your nightwear, the ambient noise and light in your room, so on and so forth....you get the picture! And these influences vary from person to person. And for any given individual, from time to time. Finding the optimal solution is not easy – it requires trying various combinations of interventions before finding one that works for you. Good sleep is a journey, not a destination. What works for you this month may not work for you the next. It requires constant attention and detective work to find what works and get good sleep.
Take my most recent string of nights with poor sleep. I had noticed that as the night progressed and the room became cooler my sleep improved. The blanket I was using to cover myself was too thick for the first half and just perfect for the second half of the night. I decided that I would use 2 layers of blankets and cover myself with the second layer only when I started feeling cold around midnight. This is the epiphany that led to the heavenly sleep alluded to above. Since writing my book I have been extra mindful about my sleep and this has aided me in my battles with the sleep demons that keep us awake.
Minding sleep has to be a conscious habit. Unfortunately, this habit is hard to acquire. As young adults, we do not experience any difficulties in getting a sound sleep and so it is difficult to adjust to the reality of middle age when sleep becomes a precious commodity. It is no wonder that in a study in America, a whopping 68% reported struggling with sleep at least once a week.
People who know me well are surprised when I confess to them that I have to work hard to get good sleep. After all, I am the person who wrote a book on sleep. Shouldn’t I be the last person to be working hard to get good sleep? The fact is that before I did the research for my book my sleep was terrible. It is only through the clear lens of the retrospective view that I can see how poorly I was sleeping and how it was affecting my health. I have come a long way since then. My deep understanding of the science of sleep has allowed me to make conscious choices that enable a night of good restful sleep. I have also come to realize that it is not just how long you sleep but also how well you sleep that matters.
So, my advise is – learn about sleep and make the behaviours that influence your sleep a matter of conscious choice. What helps you to get a good nights sleep may be very different from what helps me. But at the end of it, after experiencing a night of deep and restful sleep I can assure you that you will experience the same feeling of well-being that is increasingly my fortune these days. The bonus is that you will also become more healthy. And in these Corona times, health is a non-negotiable good; especially the positive effects of sleep on immunity. Sleep well!