The Straits Times (17 December 2018)
Most people know that not getting enough sleep is bad for one’s health. Few realise that sleeping too long may be even worse.
A local study that tracked 40,000 people over an average of 12.7 years found that both insufficient and excessive sleep increased a person’s risk of death, especially from heart attacks and stroke.
This refers to people who usually slept less than five hours or more than nine hours a night. The results were published earlier this year by the Sleep Research Society, which has over 1,200 members worldwide.
The article said that as people age, their sleep patterns tend to change. But it noted that “persistent short or long sleep of increasing sleep duration in late adulthood was associated with increased risk of all-cause mortality, especially from cardiovascular causes”.
Professor Koh Woon Puay, an epidemiologist from Duke-NUS Medical School and one of the researchers of the study, said that when the subjects were younger, with an average age of 55 years, a short sleep duration increased their risk of death by 12 per cent and long sleep by 14 per cent.
But when the participants were at an average age of 68 years – 13 years older – she said: “While short sleep increased risk of death by 11 per cent, long sleep increased the risk by 35 per cent, suggesting that the risk of death associated with long sleep may even increase with age.”
Another researcher in the study, Professor Michael Chee, director of the Centre for Cognitive Neuroscience at the Duke-NUS Medical School, said sleeping patterns change as people age.
From the study, at 55 years, 9 per cent of the 40,000 participants were short sleepers and 6 per cent were long sleepers.
By the time they were 68 years old, 11 per cent were short sleepers and 24 per cent sleep longer than is good for them.
Prof Koh said another interesting finding from the study was that people who were sleeping long hours at both the start of the study and 13 years later were at even higher risk.
They faced a 47 per cent increase in risk, particularly for cardiovascular disease death such as stroke or coronary artery disease, she said.
In contrast, those who have always had short sleep had an increased risk of 27 per cent for death. But those whose sleep pattern switched from short to long sleep fared the worst, with a 50 per cent higher risk of death than people who sleep the recommended seven hours.
However, she also noted that longer hours of sleep for older people could be the result – and not the cause – of poorer health and higher risk of death.
Prof Chee said the “sweet spot” in terms of getting the best rest among older people here is between 61 /2 and seven hours of sleep a night.
This is a little less than the seven to eight hours generally recommended internationally.
But he added: “We don’t quite know why.”
Aside from heightened risk of death, people who have insufficient sleep could also be at higher risk of Alzheimer’s Disease.
A recently released study from the Baltimore Longitudinal Study on Aging found that people who experience excessive daytime sleepiness have three times the amount of beta amyloid plaque in their brains.
High amounts of this plaque are associated with Alzheimer’s Disease.
These people also reported shorter sleep duration and poorer sleep quality.
8 tips for better slumber
Aim for seven to eight hours of sleep a night. Less than four hours and more than nine to 10 hours is likely to produce detrimental effects over time.
ARE YOU GETTING ENOUGH SHUT-EYE?
General sleep guidelines across age groups
Keep to a regular bedtime schedule and routine
Going to bed and getting up every day (even on weekends) at the same time will help to reset your internal clock and get your circadian rhythm back on track. Follow the same routine 30 to 60 minutes before going to bed. It can be anything that is relaxing and helps you to unwind: taking a warm bath, listening to soothing music or meditating.
Lower the temperature
A cool bedroom – between 20 and 22 deg C – helps to lower the body temperature, a prerequisite for deep sleep. Wearing socks and mittens is another trick to bring down body temperature. Doing so dilates blood vessels in hands and feet and precipitates cooling as the blood flows through the open channels near the surface of the skin. When body temperatures fall, sleep automatically follows.
Avoid overeating or being hungry
A bedtime snack that contains tryptophan is best, as this amino acid is converted into sleep-inducing chemicals by the body. Try a small slice of lean turkey with a piece of toast or one oatmeal cookie with a glass of milk. Avoid indulging in a sumptuous supper before bedtime because overeating disrupts sleep.
- Say no to caffeine and nicotine
Both are stimulants and disrupt sleep. Skip drinks containing caffeine, for example, coffee or tea, at least six hours before bedtime. Even if you are a hardened smoker, put a ban on night-time cigarettes.
Get at least one to two hours of sunlight daily
Light slows down the secretion of melatonin, a hormone that controls the circadian rhythm of our brain and body. Getting two hours of sunlight during the day will ensure that the natural wake-and-sleep cycles of the body are maintained.
Keep electronic devices out of the bedroom
Many people use their smartphones as alarm clocks, making it hard to unplug completely from work and social networks. Sleep-disrupting blue light, which is emitted from the screens of smartphones, tablets and laptops, suppresses the body’s production of melatonin.
Exercise earlier in the day
Exercise raises the level of cortisol, which is responsible for keeping you awake. Exercising early in the morning or mid-afternoon will ensure that cortisol levels are down to its usual amount by the time you are ready to go to bed. There should be at least three hours between your workout and your bedtime.
Avoid daytime naps
Such naps can disturb the normal pattern of sleep and wakefulness. A constant craving for an afternoon nap and excessive daytime sleepiness may be symptoms of a more serious condition called obstructive sleep apnea. Insomnia can also be triggered by physiological conditions such as sleep apnea, menopause or depression. Some drugs such as antidepressants, betablockers, diuretics and painkillers can also derail your sleep pattern. Do consult a doctor if sleep still eludes you.