'I love sleep," Ernest Hemingway once quipped. "My life has the tendency to fall apart when I'm awake, you know?"
As the science of sleep advanced inexorably through the summer, researchers around the globe have better understood the extent to which our own lives tend to "fall apart" without enough of it. Want to keep your waistline down, your mood up, reduce long-term pain from chronic conditions while putting yourself at a social advantage? Then work on your broader sleep hygiene, the experts say. The stuff of dreams? Well… yes, that as well. Simply put, sleep hygiene isn't how clean your teeth, pyjamas or bed linen is, but a suite of different daily practices and habits that are absolutely essential to having consistent, quality sleep by night and full alertness, competency and even attractiveness by day.
Sleep & the waistline
While the cognitive impairments of sleep deprivation have been known for some time, recent studies have revealed the scale at which it can cause acute, long-term health implications, from psychological and emotional health impacts, to weakened immunity and increased waistline.
A study led by Dr Laura Hardie at the University of Leeds, which involved over 1,600 adults, not only looked at the links between sleep duration, diet and weight, but also other pointers of overall metabolic health, including blood pressure, blood cholesterol, blood sugar and thyroid function.
The results indicate that those of us averaging about six hours sleep a night have poorer metabolic health and a waistline 3cm greater than those of us getting nine hours of sleep a night. Shorter sleep is also associated with reduced levels of HDL cholesterol in the blood; in layman's terms, the 'good' cholesterol that helps get rid of 'bad' fat from the circulation, thereby helping to protect us against chronic conditions such as heart disease. The current consensus is that seven to nine hours sleep is best for most adults, but are we necessarily aware when we're not getting enough?
"Sleep deprivation is basically less than six hours of sleep a night, on a continuous basis over time, and not just a single bout. Some people live on less than six hours of sleep a night, but they don't usually understand the damage this is doing to their bodies," says Dr Farrell Cahill, head of research at Medisys Health Group and a recognised leader in the field of obesity, diabetes and exercise physiology in Canada. He goes so far as to say that the cognitive impacts of sleep deprivation are just as significant as a hangover caused from binge drinking.
"The cumulative health consequences of sleep deprivation are severe, including increased risk of hypertension, diabetes, obesity, depression, heart attack and stroke. Sleep deprivation means your brain is not functioning to its optimum capability. Your brain is governing a change in your overall metabolism, so if you're sleep-deprived then your metabolism is slower, which impacts your immunity. But what also happens is that you become more irritable. Our brains need a significant amount of rest, and need to have the ability to recharge," says Dr Cahill.
When it comes to weight management, Dr Cahill points out that the reduction of sleep has been shown to significantly decrease both glucose and fat metabolism, while also inappropriately increasing appetite, leading to weight gain or obesity.
"With sleep deprivation, we see an increase in a hormone called ghrelin. With sleep deprivation, your body is trying to recover from a waning metabolism, so tries to increase appetite when it really doesn't need to. As ghrelin levels in your body increase, so too does your appetite." Often referred to as the "hunger hormone", ghrelin is a peptide hormone that not only regulates appetite but plays a starring role in regulating the distribution and rate of use of energy.
"Once your sleep falls off, the utilisation of sugars and fats becomes dysfunctional, meaning that all the tissues are getting a lack of energy supply to them. You will see a reduction in function in all organs and your central nervous system. And as your metabolism starts to wane because of increased fatigue, you will also see a decrease in muscle performance. So, it affects you neurologically and physically."
Sleep and positivity
Sleep-deprived people erode their ability to be positive-minded, thereby increasing their chance of developing or exacerbating depression, research suggests. According to a recent study published in the journal, Cognitive Therapy and Research, those who are sleep-deprived lose some of their ability to be positive-minded people.
"That may not sound serious, but medical experts say an inability to think positively is a serious symptom of depression that could be dangerous if left unaddressed," says Dr Michael Breus, a clinical psychologist and the renowned "sleep doctor" in the US, who is and both a diplomate of the American Board of Sleep Medicine and a fellow of The American Academy of Sleep Medicine. While there are many symptoms of depression, poor sleep is associated with a particularly serious sign of the condition.
"Sleep and depression seem to have a bi-directional relationship. Those who are depressed can have two sleep-related reactions: either they have insomnia or they sleep all the time. In addition, when we see people losing sleep we also see an increase in depressive symptoms, even if they are not diagnosed with depression."
Sleep and Vitamin D
A review of published research by the Department of Psychobiology at the Federal University of Sao Paulo in Brazil has concluded that vitamin D supplementation, together with good sleep hygiene, may offer an effective way to manage pain in conditions such as arthritis, chronic back pain, fibromyalgia, and menstrual cramps.
While the role of vitamin D in bone health is well known, it is now thought it also contributes to other biological processes, such as processing of sensory signals and sleep regulation. In the peripheral nervous system, the immune system participates in the inflammatory process that contributes to hyperalgesia, which is an increased sensitivity to pain.
"Sleep deprivation is an important condition related to hyperalgesia, and recently it has also been associated with vitamin D," sum up the review's authors. "Poor sleep efficiency and sleep disorders have been shown to have an important role in hyperalgesia, and be associated with different vitamin D values… Studies have demonstrated a possible action of vitamin D in the regulatory mechanisms of both sleep and pain. The supplementation of vitamin D associated with good sleep hygiene may have a therapeutic role, not only in sleep disorders but also in the prevention and treatment of chronic pain conditions."
Sleep and sociability
A recent study published by the Royal Society of Open Science suggests that people who look tired are at a social disadvantage.
"This is the classic situation where people think that no one notices how tired they look and feel. This perception then seems to effect social interactions in a negative way," says Dr Breus.
"The importance of assessing evolutionarily-relevant social cues suggests that humans should be sensitive to others' sleep history, as this may indicate something about their health as well as their capacity for social interaction," say the study authors.
"Recent findings show that acute sleep deprivation and looking tired are related to decreased attractiveness and health, as perceived by others. This suggests that one might also avoid contact with sleep-deprived, or sleepy-looking, individuals, as a strategy to reduce health risk and poor interactions… These findings suggest that sleep loss can be detected in a face and that people are less inclined to interact with a sleep-deprived individual."
Sleep & Dream Dysfunctions
"Dream dysfunctions" may predict the development of neurological disorders such as Parkinson's disease or dementia, according to new research conducted by Dr John Peever and his team at the Centre for Biology Timing and Cognition in the University of Toronto in Canada.
While examining the breakdowns in the brain circuits that cause these disorders, the team discovered that REM sleep disorders are linked to several neurodegenerative diseases that tend to occur in old age.
"We observed that more than 80pc of people who suffer from REM sleep disorder eventually develop synucleinopathies [neurodegenerative diseases), such as Parkinson's disease and Lewy body dementia. Our research suggests sleep disorders may be an early warning sign for diseases that may appear some 15 years later in life," says Dr Peever.
"Much like we see in people prone to cancer, diagnosing REM disorders may allow us to provide individuals with preventative actions to keep them healthy long before they develop these more serious neurological conditions."
Dr Breus advises that for those with disturbing dreams, using medication to reduce REM sleep can be helpful. Otherwise he suggests trying the method developed by Dr Barry Krakow at the University of New Mexico (found at nightmaretreatment.com), in which disturbing dreams and nightmares can be reduced or eliminated with cognitive-behavioural methods within weeks or months.
8 steps to support better sleep
Dr Adrian Owen, a neuroscientist at Western University in Canada, and the chief scientific officer of Cambridge Brain Sciences in that country, has been studying the effects of sleep deprivation on the brain. He suggests the sleep-deprived should adopt the following sleep habits before turning to over-the-counter sleep medication. He says:
1 Exercise regularly during the day. Physical activity during the day has beneficial effects on sleep the night after, as well as promoting more consistent, quality long-term sleep.
2 Reduce stress. Engage in stress-relieving activities, such as yoga, meditation, warm baths or other activities that help you unwind.
3 Avoid caffeine. Limit caffeine and avoid other sleep disruptors like nicotine and also avoid heavy meals close to bedtime.
4 Drink in moderation. Alcohol should be limited to a maximum of 7-9 drinks per week for women and 14 drinks per week for men, not exceeding 1-2 drinks daily. However, if you want to really improve your sleep then cut it out altogether.
5 Modify your bedroom environment. Make it a sleep sanctuary by eliminating light, noise, and excessive heat and by turning off electronic devices before bedtime.
6 Keep a consistent sleep schedule. Staying up later on weekends can throw off your biological clock and make it harder to sleep well during the rest of the week.
7 Make sleep a priority. Set a bed time and stick to it - no ifs or buts, go to bed at that time every night.
8 Not forcing it: If you're lying awake, get out of bed and do something else until you're tired again.
How much sleep is enough sleep?
"Roughly 25pc of children with ADHD actually have an underlying sleep disorder," says Dr Breus.
"For those one in four children, when they get enough sleep, their problems go away."
According to Professor Christian Cajochen of the University of Basel, a multi-disciplinary expert panel has issued new recommendations for appropriate sleep durations, which advocates wider sleep ranges for most age groups.
"What is nice about this is that it's the first time that a professional organisation comes with age-specific recommended sleep durations built on a rigorous, systematic review of the world scientific literature relating sleep duration to health, performance and safety," says Cajochen.
Newborns (0-3 months): Sleep range narrowed to 14-17 hours each day (previously 12-18)
Infants (4-11 months): Sleep range widened two hours to 12-15 hours (previously 14-15)
Toddlers (1-2 years): Sleep range widened by one hour to 11-14 hours (previously 12-14)
Preschoolers (3-5): Sleep range widened by one hour to 10-13 hours (previously 11-13)
Children 6-13 years: Sleep range widened by one hour to 9-11 hours (previously 10-11)
Teenagers 14-17: Sleep range widened by one hour to 8-10 hours (previously 8.5-9.5)
Younger adults (18-25): Sleep range is 7-9 hours (new age category)
Adults (26-64): Sleep range did not change and remains 7-9 hours
Older adults (65+): Sleep range is 7-8 hours (new age category)
Health & Living