Most urban Indians dread bedtime. Sleep disorders ensure that 93 per cent of the people living in cities don't sleep well or worse, are not able to sleep at all. What is causing us to lose sleep?
Thomas Edison, the inventor of the light bulb, once said, “Sleep is a criminal waste of time, inherited from our cave days.” His invention helped people work more easily after dark. Even today, many people, including world leaders and celebrities, boast of getting by with less sleep every night. But scientists and doctors have started seeing adverse health effects in people who deprive themselves of sleep and are trying to understand why this happens.
Dictated by our body clock, sleep allows us to rest and rejuvenate. Studies have shown that areas in the brain involved in the repair and restoration of the body’s physiological processes are more active when we sleep. They have also shown that the brain processes and consolidates memories as we sleep and the body winds down for a few hours to save energy. Sleeping takes up a third of our lifetime.
Research is on to explore all the functions of sleep. We are trying to find what happens to our biological and cognitive functions when we do not sleep enough, or when we change our sleeping time due to our lifestyle, jet lag or shiftwork. “There is still much work to be done to fully appreciate sleep and the consequences of not obtaining sufficient sleep,” says Gemma Paech, a postdoctoral research fellow at the Rush University Medical Center’s Biological Rhythms Research Lab in Chicago, USA. Understanding these aspects would help doctors devise treatments for people suffering from sleep disorders, of which there are more than 80 kinds. The most common disorders are insomnia (trouble falling or staying asleep), obstructive sleep apnoea (when walls of the throat relax and narrow, blocking the airway and disrupting breathing) and restless leg syndrome (an urge to move one’s legs). (See ‘Why we should sleep’,)
Though there is very little documentation on the extent of sleep deprivation in India, the few studies that have been done point to a dangerous scenario. According to a study conducted by The Nielsen Company, a market research company, for Philips Healthcare, 93 per cent of urban Indians in the age group of 35-65 years were sleep deprived. The 2010 study said they were getting less than eight hours of sleep a day. While 58 per cent of these Indians felt their work suffered from a lack of sleep, 11 per cent said they fell asleep at work. The study surveyed 5,600 people from 25 cities. Studies by Heather Schofield, an assistant professor in the Department of Medical Ethics and Health Policy, University of Pennsylvania, USA, have shown that low-income workers in Chennai are getting only five to five-and-a-half hours of sleep every night, possibly as a result of their living conditions.
People change their sleeping habits for a number of reasons. Take the case of civil services aspirant Mriganka Sekhar Borah, a 23-year-old who came to Delhi from Guwahati, Assam, to prepare for the exams. Like all candidates preparing for competitive exams, Borah would spend most of his time studying. But a few months ago, he took things too far. “To put in more hours of studying, I started staying up till 4-5 am. By April, I found that I could no longer go to bed in the early morning hours. At one point, I was not able to catch any sleep at all,” he says. He could not concentrate on his studies, became irritable and avoided going to bed because he was worried about not getting any sleep.
Indians in urban areas are, however, not the only ones losing sleep. A study published in the Indian Journal of Pediatrics in May 2016 on the prevalence of sleep disorders among primary schoolchildren in four urban and four rural schools showed that daytime sleepiness and symptoms of sleep apnoea were more common among rural children than children in urban areas. The reasons for this have, however, not been investigated.
Sleep disorders are not only responsible for increasing our risk factors for lifestyle and other diseases, but also come at a great cost to the economy. A study in 2006 said sleep disorders cost the Australian economy US $7.49 billion in 2004. The financial cost amounted to 0.8 per cent of the Australian gross domestic product. With 50 times the population of Australia, India’s cost of sleep disorders is likely to be exponentially higher.
Science is yet to fully understand whether “sleep deprivation leads to diseases” or whether “diseases disrupt sleep”. When their bidirectional relationship becomes clear, it can be used to devise targeted therapies for sleep disorders and reduce the economic burden on public health.
Sleep is dictated by our body clock, which is, in turn, synchronised with the 24-hour rotation of the earth. This circadian rhythm tells us when it is time to sleep. Genetic factors determine our body clock, but their influence is limited. Lifestyle and environmental factors interfere with our genetic blueprint and contribute to sleep disorders. Even among twins, genetic factors contributed to only 33-38 per cent of cases of insomnia, while the remaining was triggered by the environment. The contribution of genes declined with age, the study, published in the journal Sleep, revealed.
Whether rich, poor, rural or urban, we are surrounded by triggers of sleeplessness. Noise pollution, light pollution, temperature, humidity and lifestyle choices such as working in shifts and travelling across time zones can wreak havoc. Researchers are divided, though, over which of these environmental triggers is the biggest culprit behind sleeplessness.
It could be attributed to the artificial light emitted by computers and mobile phones, say some studies. The suprachiasmatic nucleus in our brain, which receives light cues from the environment and sets the circadian rhythm, can be disturbed by something as simple as the e-reader. Sleep scientists from the US and Germany asked 12 healthy people to read a book on a light-emitting device (LE-eBook) before going to sleep for five days. The same people then read a paper book for five days under the same conditions. Participants took longer to fall asleep after reading an LE-eBook and experienced reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock, and reduced next-morning alertness, according to findings published in PNAS in January 2015. The situation is likely to worsen in India as e–reader manufacturers are aggressively marketing their products. According to media reports, Amazon’s e-books business, including e-readers, is growing over 200 per cent year-on-year.
Richard Stevens, a professor at the University of Connecticut’s School of Medicine, adds another dimension. He says that people are unable to sleep because they are darkness-deprived. He cites a study which shows that people in areas where there is no electricity sleep less than those in urban areas. Yet these people do not show the adverse effects of sleeplessness. “Too much light in the evening is bad for sleep; though the term ‘too much’ must be specified,” he says. In the times before electricity, humans transitioned to night-time physiology at sunset when the body temperature drops, metabolism slows, hunger abates, sleepiness increases and melatonin begins to rise. A campfire or a candle does not delay this transition, yet we can see by its light. However, a bright compact fluorescent light (CFL) will probably delay the transition in the evening depending on how close you are to it, he explains.
Changes in diet may also affect sleep quality, according to Michael A Grandner, director of the Sleep and Health Research Program at the University of Arizona, USA. “Poor diet contributes to poor sleep quality and vice versa. Poor diet can lead to dysregulation of physiological systems. This can lead to physical and mental discomfort which can, in turn, cause sleep problems. And sleep problems can lead to altered patterns of food intake that are unhealthy,” he says. Palmitate, an antioxidant commonly found in processed and fast foods, can reset circadian clocks in some cells, but not all. “Having some cells functioning in different time zones has consequences for our health,” says David J Earnest, a professor of neuroscience and experimental therapeutics at Texas A&M University in an article on the news website, The Conversation. Palmitate also induces inflammation in different cell types. These two effects peak at night in fat cells. While there is no good time to eat saturated fat, it is probably not a great idea to eat a meal rich in these “bad” fats late at night, suggests Earnest.
While the noise of life-saving machines has been known to affect the sleep of patients in hospitals, noise tends to affect our sleep in homes as well. A study published in the Annals of Occupational and Environmental Medicine in September 2016, showed that exposure to aircraft noise disturbed the sleep of people living near an airport. Insomnia and excessive sleepiness during the day were approximately three times higher among those exposed to aircraft noise than those who were not. Living near a busy road can produce a similar effect. Researchers have also associated night-time traffic noise with sleep disturbances, sleep fragmentation and sleep-disordered breathing and found that these disorders are more common in women. The study was published in Sleep Medicine in March 2014. Mathias Basner, associate professor at the Perelman School of Medicine, University of Pennsylvania, ranks noise as a big sleep disruptor. “As noise is ubiquitous, its contribution to sleep disturbance and sleep loss should not be underestimated,” he says.
Shift work too has emerged as one of the biggest triggers of sleeplessness and even doctors are at the receiving end. To study sleep deprivation among doctors, researchers divided 18 physicians aged 26-33 years into two groups: those with no night work and those who did a minimum of 12 hours of night work per week. The results showed that the doctors who did night work were unable to complete their sleep during the day and had higher daytime sleepiness. This resulted in reduced attention and delayed response to the stimuli, which may compromise patient care as well as the physician’s health and quality of life, says the study published in Acta Médica Portuguesa, a journal published by the Portuguese Medical Association. Paech says longer working hours (in shiftwork or even during normal office hours) probably affect more people than sleeping disorders.
Decoding the links between these external factors and sleep, circadian rhythms, metabolism, hormone functioning and other physiological processes will help develop solutions to benefit people in the real world, sums up Grandner.
Gaps in treatment
But before we can begin to treat the problem, it is important to conduct a large scale study to find out the true extent of sleep deprivation and disorders in the Indian population. For example, insomnia data for India is patchy, according to M S Kanwar, president of Indian Sleep Disorder Association. But such a study would be costly as it would require a large number of people to contact a large number of households to come up with accurate findings. Meanwhile, people continue to lose sleep.
As soon as civil services aspirant Borah realised that he was probably suffering from some kind of disorder, he sought medical help. The doctor prescribed a sleep-inducing medicine for a few days and then, impressed on Borah to introduce important lifestyle changes (see ‘How to sleep better’). Not everyone seeks professional help though. A study released in 2013 by the All India Institute of Medical Sciences (AIIMS) showed that only 700 patients had attended a specialty sleep clinic in eight years. “Given that more than half of the population suffers from some sleep disturbance or the other at some point in life, the expected numbers of referrals to specialty sleep clinics were expected to be very high,” the study said. It reasoned that there was possibly a lack of awareness, both among the patients as well as their primary physicians.
Due to this lack of awareness, people attempt self-medication, says Manjari Tripathi, a neurology professor at AIIMS. “Medicines like Alprazolam are addictive and should not be consumed, but are available over-the-counter for insomnia,” she says. Patients with obstructive sleep apnoea often worsen their condition with self-treatment. Doctors prescribe the use of Continuous Positive Airway Pressure (CPAP) machines to patients with moderate apnoea to help them breathe in and Bilevel Positive Airway Pressure (BiPAP) machines to patients with severe apnoea to help with both breathing in and out. But instead of consulting a neurologist or pulmonary medicine specialist to decide which machine would suit them best, patients directly approach medical equipment vendors. As BiPAP machines are more expensive, vendors end up recommending them, explains Tripathi, without any benefits for the patients.
Ideally, people who are experiencing trouble sleeping must consult a doctor and the doctor must perform polysomnography or a sleep study to understand the problem, says Kanwar. The result is a polysomnogram which provides data on multiple biological functions during sleep, such as brain wave activity, eye movement, muscle tone, heart rhythm and breathing via electrodes with monitors placed on the head, chest and legs. The test costs Rs 16,000-20,000. “This high cost is a significant barrier to treatment. People have to pay out of their pockets since it is not covered under insurance,” says Manvir Bhatia, a senior consultant in neurology and sleep medicine in Delhi.
There are also gaps in our understanding of sleep disorders. “We need to better understand the incidence, prevalence and variations in sleep disorders in India, and also pursue research on why such differences exists,” says N Ramakrishnan, director at Nithra Institute of Sleep Sciences, Chennai. H N Mallick, president of the Indian Society for Sleep Research, adds, “We teach sleep (as a subject) for hardly four to five hours in the entire curriculum in medical colleges. We must have at least three lectures in the basic sciences and another four-five lectures across the curriculum.”
Why we should sleep
|Why we should sleep
Sleep helps our body repair and recharge. But sleep disorders affect these functions and can lead to serious health issues
while SCIENCE prescribes a daily average of eight to 10 hours of sleep for all adults, most people do not share similar sleeping habits. Genes and external environmental factors have retuned our body clocks so that we go to bed at different times and sleep for different durations than others.
But humans need good quality sleep to remain healthy. As we sleep, we alternate between periods of rapid (REM) and non-rapid eye movement (NREM). It is during these stages of deep NREM sleep that our body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system.
There are 80 kinds of sleep disorders that affect us, says Manvir Bhatia, a senior consultant in neurology and sleep medicine in Delhi. These can be classified into three main typesÐinsomnia, parasomnia and hypersomnia. A person is suffering from insomnia when one cannot fall asleep, cannot stay asleep or wakes up too early. Hypersomnia includes feeling very sleepy and exhausted, not being able to concentrate at work and the tendency to sleep off during activities like driving. In parasomnia, people display abnormal behaviour in sleep, including kicking, walking, and shouting. Another common condition is obstructive sleep apnoea, which is interrupted sleep caused by periodic gasping or "snorting" noises or momentary suspension of breathing.
"Insomnia has numerous causes ranging from something as simple as poor lifestyle to apnoea to depression or any medical disorder. People who have depression, people who have cough, women with PMS and pregnant women have sleep issues. Any change in the body affects your sleep," says Bhatia. She adds that some conditions are hereditary.
A 2015 study on corporate employees, funded by healthcare company Abbott India Ltd, found the prevalence of insomnia in 13.8 per cent of over 600 participants. Common co-morbid conditions associated with insomnia such as anxiety, hypertension and depression were significantly higher. The study also said that alcohol consumption was significantly higher among the sufferers of insomnia. Insomniacs agreed that insufficient sleep affected their health, performance at work, household duties and relations with family.
Obstructive sleep apnoea hypopnea syndrome (OSAHS) is a far more prevalent disease in India than generally believed, says another study published in Perspectives in Medical Research in 2013. OSAHS is characterised by snoring, snoring which disrupts sleep, and repeated episodes of complete or partial obstruction of the pharynx during sleep. These result in a drop in blood oxygen levels at night, frequent arousals, cardiac abnormalities and excessive daytime sleepiness. Sleep disorders also vary in different parts of the country. According to a study published in the Journal of Diabetes Science and Technology in 2010, the prevalence of snoring and daytime sleepiness is higher among urban south Indians when compared to people in western parts of the country. Another study published in the American Journal of Respiratory and Critical Care Medicine in 2004 on western India reports habitual snoring in 26 per cent and daytime sleepiness in 22 per cent of their subjects.
Good quality sleep is as integral to living a healthy life as are a balanced diet and exercise. Mounting evidence shows that sleep deprivation and sleep disorders contribute to the development of lifestyle diseases such as diabetes and cardiac diseases. Sleep is also linked with cancer and mental health
- DIABETES Evidence | A study published in Sleep Medicine in 2015 asked 2,579 healthy adults between the age of 40 and 70 years to provide details of how much they slept every day. After an average of 2.6 years, 558 (21.6 per cent) of them had developed metabolic syndrome, a group of risk factors for diabetes and cardiac diseases. Those who slept for less than six hours were more susceptible.
- Mechanism | In an experiment, people's circadian cycle was misaligned by imposing short night-time sleep. This resulted in them being awake during their biological night. Their melatonin levels, associated with the onset of sleep, also remained high. Eating food during this period made things worse.
- Implications | India has the second highest number of diabetics in the world. The number of people suffering from the disease has risen from 11.9 million in 1980 to 64.5 million in India in 2014.
- Evidence | There is evidence that disturbed sleep or lack of sleep is a risk factor for Alzheimer's disease. Studies suggest that people with sleep problems had a 1.55, 1.65 and 3.78 times higher risk for Alzheimer's, cognitive impairment and preclinical Alzheimer's respectively than people without sleep problems. The study, published in Sleep in September 2016, says that some 15 per cent of Alzheimer's disease in the population may be attributed to sleep problems.
- Mechanism | Researchers at Johns Hopkins Bloomberg School of Public Health in Baltimore found that sleep deprivation results in an increase in the levels of beta-amyloid in the brain. This is a toxic protein that forms plaques in the brains of people suffering from Alzheimer's. Another team of scientists at the University of Toronto found that sound sleep seemed to blunt the effects of APOE-E4, a gene that increases the risk of developing Alzheimer's disease.
- Implication | More than four million Indians have some form of dementia. Alzheimer's disease is the most common type of dementia.
- Evidence | In a survey between 2006 and 2008 on 28,150 American adults aged 21 to 65, it was found that short sleep was associated with more time spent on eating and drinking. This suggests a potential for increased calorie intake in the form of beverages and distracted eating which can lead to obesity.
- Mechanism | Insufficient sleep affects the hormones by increasing ghrelin and decreasing leptin. Ghrelin is a gut hormone. Its levels are highest before meals. Increased ghrelin stimulates appetite and food consumption. Leptin has the opposite effect on appetite, fat oxidation, and energy expenditure. In a study where people slept for four-hour periods, the ratio of ghrelin-to-leptin increased by more than 70 per cent and led to an increase in the consumption of 350-500 calories per day.
- Implication | India has the third highest number of obese people in the world.
- Evidence | Short sleep duration is associated with an increased incidence of cardiovascular diseases such as coronary artery disease, hypertension and arrhythmias, says a review published in Neuroscience & Biobehavioral Reviews 2016.
- Mechanism | Researchers compared the duration of sleep with changes in blood and serum. They wrote in Scientific Reports in 2016 that sleep loss decreased the production of cholesterol transporters and increased inflammation.
- Implication | The cardiovascular disease death rate of 272 per 100,000 population in India is higher than the global average of 235 per 100,000 population. Premature mortality in terms of years of life lost due to cardiac diseases in India increased by 59 per cent from 1990 to 2010.
- Evidence | Studies have established a link between the lack of sleep with breast, prostate and colorectal cancers.
- Mechanism | Lack of sleep increases inflammation and disrupts the normal immune function of the body, which may promote cancer development. In addition, the hormone melatonin, which is produced during sleep, may have antioxidant properties that help prevent cellular damage. Researchers calculated a 50 per cent increased risk of colorectal cancer in people sleeping less than six hours per night.
- Implication | A little more than one million new cases of cancer are diagnosed every year in India which has a population of 1.2 billion. The incidence of cancer in India is lower than the global average, but cancer cases are expected to increase to 1.73 million by 2020.
- Evidence | Studies show that chronic sleep disruptions set the stage for negative thinking and emotional vulnerability. It has been observed that sleep problems develop before major depression in patients. In 635 Japanese day workers with sleep problems, it was seen that the risk of suicidal ideation increased in people with multiple sleep problems.
- Mechanism | Mental illness breaks down the internal synchronisation of the circadian network. Sleep and circadian-rhythm disruption in patients with conditions such as schizophrenia occur whether or not they are on medication. This suggests that mental illness and sleep disruption may share common and overlapping pathways in the brain.
- Implication | A third of the global burden of mental, neurological and substance use disorders occurs in India and China. The burden of mental illness will increase at a faster rate in India than in China over the next 10 years. In 2013, 31 million years of healthy life were lost due to mental illness in India. By 2025, this number will increase by 23 per cent to 38.1 million years.
How to sleep better
|How to sleep better
It is important to maintain `sleep hygiene'. This means maintaining a sleeping routine and sleep duration
Sleep DEPRIVATION throws the circadian rhythm out of sync and affects the hormone balance in the body. For example, levels of the adrenocorticotropic hormone, which stimulates the production and release of cortisol, are higher in people with insomnia.
Cortisol is known as the "stress hormone" and regulates changes in the body in response to stress. Less sleep can also throw our prolactin levels out of balance, weakening the immune system and resulting in carbohydrate cravings during the day. Hence, good sleep is important and doctors recommend a few principles of "sleep hygiene":
- Going to bed and waking up at fixed times every day
- Creating a relaxing bedtime routine and not using the bed for activities such as working on the laptop
- Going to bed when tired
- Maintaining a comfortable sleeping environment that's not too hot or cold
- Reducing noise in the bedroom
- Not taking naps during the day
- Avoiding caffeine, nicotine and alcohol late in the evening
- Avoiding heavy meals late at night
- Reducing exposure to artificial lights
- Increasing exposure to natural light
In addition to some lifestyle modifications, policy fixes can also alleviate a part of the problem. Allowing workers to choose flexible hours so that they can sleep at a time that best suits their circadian rhythm could be a solution to help people sleep better, suggests Paech. If this is not possible, offices could provide places to nap. For example, Google offices have set up “nap pods” or reclining chairs which shut down external stimulus and provide a private space with soothing music and a timer to enable employees to catch a nap.
Basner recommends that there should be a legislation to prevent operating loud machinery at night. Policies could also ensure that the main sleeping hours are protected from noise. The trick would, however, be to enforce these limits. People can also take some steps at the personal level. For example, they can check the noise level while looking to buy or rent a house/apartment. One could also choose a bedroom that does not face the road, install sound-insulating windows or keep windows closed at night, suggests Basner.
While there is no government programme yet in India to deal with the health outcomes of sleep disorders, the world is waking up to the dangers of sleeplessness. Twenty-four hours without sleep or a week of sleeping for only four to five hours a night can induce impairment equivalent to a blood alcohol level of 0.1 per cent, which is reached after consuming four or more drinks. This can result in an increase in the number of road accidents. Many states in the US, such as New Jersey, consider driving while being sleep deprived an offence. But detecting sleep deprivation is not as easy as detecting driving under the influence of alcohol because there are no devices such as breathalysers to ascertain drowsiness.
Till these are developed, governments are attempting to reduce sleep-deprived driving through educational messages and by building roads with dents, known as rumble strips in the US. These cause noise when drivers wander outside their lane. In western Australia, a “Driver Reviver” programme allows drivers to get free coffee from partnering coffee chains to help them stay awake.
People remain unaware of the gravity of sleep deprivation and the effects it has on the physiological process. “People are aware of heart diseases or cancer because we can see their effects on our near and dear ones. A similar awareness needs to be generated around effects due to sleep loss,” says Birendra Nath Mallick, a professor of neurobiology at the School of Life Sciences, Jawaharlal Nehru University, Delhi.
In a majority of cases, it is easy to avoid sleep deprivation and even treat the problem. Cognitive behaviour therapy (changing the way you think) and mindfulness therapy (a cognitive therapy combined with meditation) can be used to treat many cases of insomnia. Most of all, it is imperative that we make sleep a priority. A good night’s sleep will not only improve our quality of life, but also reduce the burden of chronic diseases that economies can ill afford to bear.
The article was originally published in March 1-16 issue of Down To Earth
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