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.”