In a recent interview with the Post , Hong Kong leader Carrie Lam Cheng Yuet-ngor revealed that she only gets three to five hours of sleep per night due to her taxing schedule. For many Hongkongers, this is a familiar complaint that is often seen as part and parcel of the city’s “work hard, play hard” culture. Some may even view getting little sleep as a badge of honour that is a mark of how “busy”, and therefore successful, they are in their professional lives. But the widespread nature of this problem in Hong Kong should not be ignored. A 2003 University of Hong Kong study found that sleep deprivation affected a staggering 92 per cent of working-age city residents, while a more recent 2011 Health Department census found that over a third of adult Hongkongers failed to get seven hours of sleep per night on average. Hong Kong is not alone when it comes to having a citywide sleep problem. Some 44 per cent of Singaporeans sleep for fewer than seven hours a night on weekdays, a study from last year found. Meanwhile, a third of Londoners have said they are too busy to get enough shut-eye, according to a 2016 survey. Dr Samson Fong from the Hong Kong Society of Sleep Medicine recommends limiting the use of digital devices in the evening and developing a regular sleep schedule. “It is a good habit to go to bed and get up at nearly the same time both on weekdays and weekends,” he says. To help, Fong recommends a number of good sleep hygiene practices. The bedroom should only be for sleeping and not watching television or surfing the internet. Vigorous exercise should be avoided for at least three hours before bedtime, along with heavy meals, caffeine and cigarettes since nicotine is a stimulant. Fong also warns against drinking alcohol as a sleep aid – a warm bath may be more helpful. Long working hours and digital devices blamed as more than 2 million Hongkongers suffer from insomnia What are the causes and symptoms? Sleep deprivation has many telling signs: besides frequent yawning, sufferers may experience memory and concentration problems, slower reaction times, mood swings and irritability, as well as unexplained aches and pains. In Hong Kong, the common causes of sleep deprivation are long working hours, stressful lifestyles, poor diet habits such as relying on caffeine, and the overuse of digital devices emitting blue light that disrupts humans’ natural circadian rhythms. “Humans are the only species that deliberately deprive themselves of sleep for no apparent reason,” the world-renowned sleep expert Matthew Walker previously told The Guardian newspaper in an interview. How getting too little sleep can shave years off your life Unsurprisingly, getting less than seven hours of sleep per night carries huge health risks. Numerous studies have shown that the amount of sleep you get directly impacts your life expectancy: British and Italian scientists found in 2010 that people who regularly slept fewer than six hours per night were 12 per cent more likely to die early compared with those who got six to eight hours. Obesity and weight gain are also common side effects of long-term sleep deprivation, since sleep helps the body regulate its levels of blood sugar and appetite-controlling hormones. So the next time uncontrollable hunger cravings strike, it could be down to whether you’ve had enough sleep lately. In terms of mental health, getting too little sleep over one’s lifetime carries a significantly increased risk of Alzheimer’s in old age. According to the Centre for Health Protection’s 2013 sleep report, insomniacs are also 10 times more likely to have depression and 17 times more likely to have anxiety. Mental health pilot scheme in Kowloon East hospitals will cut waiting times for depression, anxiety or insomnia sufferers Tips and tricks for overcoming sleep deprivation To combat this, the US-based National Sleep Foundation recommends getting an “ideal” seven to nine hours of sleep daily for adults. However, this changes depending on your age: people older than 65 should get seven to eight hours, while teenagers and school age children should get up to 11 hours. The foundation also noted that sleep’s health benefits not only depend on duration, but also on the quality of sleep and its timing during the day. What will happen if you sleep for ... Less than seven hours Even sleeping for 15 minutes short of seven hours makes a noticeable difference to your health. Without medical help, an adult regularly sleeping 6.75 hours per night is only predicted to live until their early 60s. Less than six hours Adults over 45 who sleep fewer than six hours per night are 200 per cent more likely to suffer a heart attack or stroke in their lifetime. A South Korean study from 2015 also found that adults in this category were more likely to display risk factors for diabetes and heart attacks, including high blood sugar, high cholesterol, extra belly fat and high blood pressure. The fruit and veg to eat for headaches, insomnia, stomach pain and sloth Less than five hours A 2007 British study of 10,000 civil servants found that those who slept five hours or fewer per night were nearly twice as likely to die from all causes, but especially heart disease. This is backed up by a 2014 Harvard Medical School study which shows that people who get five hours’ sleep or less are 15 per cent more likely to die at any age, from anything. Drivers who have had less than five hours’ sleep the night before are 4.3 times more likely to be involved in an accident. Less than four hours Losing out on one night of adequate sleep can have a huge impact on your immune system. According to sleep scientist Walker, sleeping for four hours a night slashes the amount of cancer-fighting white blood cells in your body by 70 per cent. What insomniac fruit flies tell us about the importance of a good sleep Who are the most sleep-deprived people in Hong Kong? Chronic sleep deprivation has long been linked to those who work night shifts. The regular disruption to humans’ natural body clock in this way makes it harder for them to get enough sleep during the day. Moreover, it increases the likelihood of developing various cancers including breast, prostate and colon cancer. Other health conditions associated with shift work are stomach and digestive issues, as well as cardiovascular disease. Other professions with widespread sleep deprivation problems are in the financial industry, where long hours and frequent post-work socialising with clients take their toll. Domestic helpers are also expected to be at their bosses’ beck and call virtually 24 hours a day, on top of living in typically cramped, squalid conditions. Hongkongers aged 55 to 64 were the most likely out of all age groups to suffer from insomnia linked to frequent sleep deprivation, according to the 2013 Centre for Health Protection survey.