Sleep deprivation: more than just a few broken nights
Everyone has had a bad night's sleep, right? That's true. Everyone can recall sleepless nights with sick children or restless tossing and turning with haunting thoughts. As long as we're able to follow up with good or better nights after nights with insufficient restorative sleep, there's no problem. Sleep deprivation that doesn't significantly hinder you during the day is called pseudo-insomnia, although it's still real and unpleasant for those experiencing it. When it does hinder, but not longer than three weeks in a row and occurring at least three times per week, it's called acute insomnia. When bad nights persist for longer than three weeks consecutively, it's referred to as chronic insomnia.
Difficulty falling asleep (where sleep takes more than 30 minutes to occur), frequent awakenings during the night, or waking up too early in the morning negatively affect daytime functioning. Furthermore, sleep disorders are also classified by severity or cause and whether they involve falling asleep or staying asleep.
The World Health Organization (WHO) defines insomnia as a complaint of subjective sleep deprivation accompanied by daytime symptoms such as fatigue, sleepiness, irritability, dizziness, concentration difficulties, and reduced performance. Sleep deprivation can refer to both sleep quantity and sleep quality.
Insomnia is, in any case, a 24-hour problem because chronic sleep deprivation is also felt throughout the day. For this reason, it is advisable to consider the sleep quality of employees as part of their health and pay attention to it during periodic checks by the occupational physician or in surveys on general well-being.
“Sleep deprivation can refer to both sleep quantity and sleep quality”
Sleep needs vary from person to person and change over the course of life. For example, as someone ages, their nighttime sleep becomes shallower and shorter. Approximately two-thirds of adults sleep an average of seven to eight hours per night. Some manage with six hours while others truly need eight hours.
Genetics play a role, but periods of increased stress and the need to recover from it also temporarily increase our sleep needs.
The structure of our sleep is a delicate interplay of genetics, health, biochemistry, and environmental factors. According to large-scale health surveys of the Belgian population (1) conducted by Sciensano every five years, our sleep quality is not improving. In 2001, 20% of respondents aged 15 or older reported recent sleep problems. In 2013, that figure rose to a staggering 30%. In 2018, 23% specifically mentioned sleep problems due to general worrying.
Our country ranks among the leaders in terms of the highest use of sleep and sedative drugs, with a daily dispensing of 1.14 million unit doses in Belgian pharmacies (2).
Women sleep worse than men, and older people sleep worse than younger ones, as do people from lower-educated groups. The largest increase in sleep complaints occurred in the age group under 55, in the active working group. Naturally, these data say something about the need to monitor the sleep quality of employees in general and of certain groups in particular.
How do you know if you're getting enough sleep? (3) Are you a short or long sleeper? An early bird or a night owl? Whether you are a short or long sleeper is less important than whether or not you are getting enough recovery hours. On the other hand, sleeping too much is also detrimental.
How do you know what your ideal sleep need is? Online, you can find questions to gauge your own experience, such as these:
- How well do you function during the day?
Making more mistakes or performing slower than usual indicate that you are not functioning optimally and are less energetic.
- Do you often find yourself getting irritated?
Increased irritability and impatience indicate that your mood is less resilient. Rapidly changing moods can be a precursor to greater mental challenges such as depression or burnout.
- Do you experience clear stress?
Someone experiencing stress feels both physical and mental pressure. Exhausting for your body and mind, so you should incorporate longer sleep time during these periods.
- How do you sleep during your vacation?
Weeks without setting an alarm are an indication of your more natural sleep pattern. Staying up late but sleeping in? Getting up early but taking a nap? It's related to your biorhythm.
- Do you fall asleep easily?
Taking longer than 15 minutes to fall asleep or waking up frequently at night may indicate that you are not sleeping efficiently. You should then add this "missed" time to meet your full sleep needs.
- How do you feel upon waking?
Feeling very groggy and not refreshed can be a sign of both too much and too little sleep.
- Take a look at your parents. How did they sleep as adults at your age?
You probably recognize your own needs, such as going to bed early and also waking up early. Heredity plays a major role in your sleep needs and biorhythm.
Causes of unwanted wakefulness
In addition to insomnia, better known as the classic difficulty falling asleep mainly due to psychosocial causes (stress, frustrations, worrying, an unhealthy psychosocial work climate, ...), structural medical causes can also significantly hinder a sufficiently deep and long sleep. For example, restless legs syndrome, an unpleasant, difficult-to-describe feeling in the legs in the evening and at night that diminishes with movement. Or parasomnia, where someone exhibits unusual behavior such as sleepwalking during sleep. With hypersomnia, someone sleeps enough at night but still experiences uncontrollable attacks of extreme sleepiness during the day.
Quite well known nowadays is the obstructive sleep apnea syndrome (OSAS), commonly known as sleep apnea. A condition where you stop breathing ten to forty times per hour for ten seconds to a minute. According to recent literature reviews covering 16 countries, sleep apnea occurs in 3.9% (New Zealand) to 49.7% (Switzerland) of men (4). This difference can be explained by the lack of international consensus on the diagnostic criteria for sleep apnea. Specific figures for Belgium are not available yet, but some sources (5) claim that about one in two working men and one in four working women over 40 suffer from sleep apnea. It is not age-related but usually affects middle-aged men or women after menopause.
Disruption of someone's biological clock is also such a structural medical cause. This extensively researched yet somewhat underestimated problem, often with roots in work-related issues, deserves extra attention.
The specific role of shift work and night work
Human sleep normally relies on the circadian rhythm, a biological rhythm with cycles of about 24 hours. This rhythm determines almost all major systems in the body: not only the sleep-wake cycle but also bodily processes such as the immune system and hormone secretion. It determines when someone gets tired, would go to sleep and wake up again, what you eat at a certain time, your body temperature, heart rate, and digestion, but also your emotions, mood, and energy level depend on it. The circadian rhythm shifts as you enter a different stage of life but remains personal at the same time. Morning people have a different sleep-wake rhythm than evening people, but everyone's biological rhythm naturally has a peak during the day and a trough at night, allowing us to be active during the day and recover from it at night. However, we can also adjust this biologically built-in and finely tuned clock. And therein lies the risk: “meddling” with the natural rhythm can disrupt the whole system, leading to significant health issues.
"Meddling with the natural rhythm can disrupt the whole system"
This is because the circadian rhythm is naturally controlled by daylight but also by "zeitgebers" or time anchors such as the clock, the news bulletin, or increasing traffic noise. For example, if we add too much artificial light by choice or ignore the time anchors, it has a disruptive impact. The time anchor of those who work in shifts can sometimes clash with societal and family time. Work hours then force the biological rhythm to adapt while the environment and light/darkness push back towards the normal day-night rhythm. Not everyone is immediately affected equally, but there are physiological changes that become more important as someone spends more time in rotating shifts or night work. Chronic sleep disorders often originate here.
FNV, the largest Dutch trade union, published "Licht in de nacht" in 2011 after conducting research on this matter (6). The argument was that humans are not nocturnal by nature and that for the more than one million Dutch people who work at night, there are certain risks that require caution and accompanying measures.
Proven impact on body and mind
Shiftwork Metabolic Syndrome (SMS)
Our vital organs also contain "clock cells". Synchronized with the master clock in our brains, they regulate the normal day-night pattern. However, the clock cells in the liver are separately controlled by the timing of food intake. Deviating from the "normal" pattern with three meals per day (breakfast in the morning, lunch in the afternoon, and dinner in the evening) disrupts glucose metabolism. The digestive system is much less efficient at night under the influence of the biological clock. Combined with unhealthy/different eating habits during night shifts, this leads to an increase in blood sugar levels. The connection between resistance to endogenous insulin, type 2 diabetes, reduced fat digestion at night, increased cholesterol, and overweight turns varying eating patterns into a serious burden on the health of shift workers in the long term. According to research, this syndrome occurs after just six years of shift work. The severity also depends on the rotation followed by the work schedule. Overall, SMS is seen as an independent risk factor in the development of cardiovascular diseases.
Statistics from numerous studies show that insomnia is associated with poorer health. The blunt statement "too little sleep makes you dumb, fat, and sick" unfortunately holds true. Sleep disorders can lead to physical complaints such as:
- reduced immune system function: more susceptible to relatively harmless colds and flu symptoms;
- stomach and intestinal problems;
- type 2 diabetes: problems with staying asleep and waking up too early are linked to long-term elevated blood sugar levels because it causes the release of cortisol (the stress hormone), which can promote the development of diabetes. Research also shows that the misalignment of the sleep-wake rhythm on one hand and the work-rest times on the other hand disrupts glucose-insulin, leading to type 2 diabetes, glucose intolerance, or even insulin resistance after just one bad night. This is the so-called Shiftwork Metabolic Syndrome.
- overweight: 53% of shift workers have a higher BMI compared to 36% of non-shift workers. This is influenced by having more appetite for calorie-rich food in the evening, as well as irregular eating times and a less active movement pattern. According to research, poor sleepers also eat more than people who sleep sufficiently;
- elevated cholesterol levels: shift workers have higher cholesterol levels compared to day workers;
- elevated blood pressure: three times as many shift workers as colleagues working during the day have high blood pressure;
- higher prevalence of cardiovascular diseases: the previous health effects increase the risk of a heart attack up to 2.8 times higher than normal. People in shift work also tend to smoke more than colleagues in day shifts;
- development of certain cancers: in 2007, the International Agency for Research on Cancer of the WHO classified night shift work as "probably carcinogenic" as the permanent disruption of the biological sleep-wake sequence and the use of artificial light promote tumor development. This conclusion was reached after finding that hospital staff and flight attendants with more years of service had more cases of breast cancer due to the influence of the sleep hormone melatonin on the hormone estradiol. A more recent publication in Science Advances described how when the circadian clock is disrupted, a cancer signature gene that can cause lung tumors (HSF1) is involved. The lungs are subject to strict circadian control and seem particularly vulnerable to a disrupted biological clock.
During the day, not only the body but also the mind experiences significant effects of chronic sleep deprivation, and here too, it makes a difference whether you work day shifts, rotating shifts, or (permanent) night shifts. Both our mental capacities and mental well-being decline:
- memory: what we learn "solidifies" during our sleep. Sleep deprivation limits memory formation, leading to forgetfulness, absent-mindedness, and overall performance decline;
- decreased alertness, attention, and concentration negatively affect coordination and reaction speed. The Flemish Foundation for Traffic Science compares driving while fatigued to driving under the influence. A few nights of only five hours of sleep in a row increase the risk of an accident by up to six times. If you sleep an hour more those nights, it's still like driving with a blood alcohol content of 0.6 promille;
- decreased awareness makes it harder to think logically, assess complex situations, make decisions, and communicate. Sleep deprivation is a proven factor and should therefore always be considered in the root cause analysis of occupational accidents;
- lack of energy (sometimes even excessive sleepiness) results in reduced efficiency and productivity;
- depression and other mental problems such as anxiety and addiction are relatively more common with prolonged insomnia and are in turn linked to concentration difficulties, decreased judgment and awareness, and reduced social interaction.
Tips for an alert approach to a looming problem
The annual cost of sleep deprivation could amount to around €2000 per employee. Direct costs for medical treatment, indirect costs of morbidity and mortality, but also related costs due to sick leave and material damage after (occupational) accidents resulting from insomnia. Research (7) shows that insomniacs have double the number of work accidents compared to good sleepers and that five percent compared to two percent annually had motor vehicle accidents due to sleepiness behind the wheel. Colleagues of sleepy employees also face extra risks and sometimes have to replace absentees and take on additional or unfamiliar tasks.
Employees are responsible for their sleep hygiene, something they certainly pay attention to when they are in a shift system. Furthermore, taking the initiative to timely address any work-related stress with a supervisor or the confidential advisor can help to prevent sleep complaints and subsequent mental and other problems.
"Both employees and employers can play their part in addressing this looming problem"
Employers can support them in this, supported by internal and external services for prevention and protection at work, by:
- creating an open climate where stress complaints can be discussed together in a solution-oriented manner. Read also “Burn-out: hoe kunnen werkgever en werknemer zich er samen tegen wapenen?" on this blog page;
- being alert to the possible correlation between sick leave and sleep problems;
- sensitizing employees through, for example, toolbox talks about the DNA of restorative sleep but also about the causes, progression, and potential consequences of chronic sleep deprivation with concrete and achievable tips on how to address it (nutrition, eating patterns, exercise, light therapy, relaxation techniques, support by sleep specialists, ...);
- including workshops on healthy sleep by an expert in the GPP and YAP;
- preventively detecting possible sleep apnea in risk groups such as professional drivers (up to 8 times more likely to have sleep apnea) or from a certain age (45 years for shift workers). Nowadays, this can also be done at home with a portable measuring device;
- optimizing working conditions so that people can work more according to their own biorhythm. Dr. Inge Declercq, neurologist and sleep expert (UZA), for example, advocates outdoor breaks for those who have to work in dark spaces, but especially emphasizes a well-thought-out rotation system for shift work. Detailed advantages and disadvantages
- an example of all systems can be found in the report “Licht in de nacht” (8);
- in surveys or contacts with occupational physicians, pay attention to the mental well-being of employees;
- include, in risk analyzes of more monotonous tasks, excessive daytime sleepiness as a risk factor;
Sleep and sleep deprivation are not purely personal matters when it comes to occupational safety. With the necessary caution in approach and sound information in mind, you may not yet be able to sleep soundly, but you will certainly awaken people.
(1): https://www.sciensano.be/nl/projecten/gezondheidsenquete-0
(2): https://www.health.belgium.be/nl/news/world-benzo-awareness-day
(3): https://www.avogel.be/nl/advies/slaap-stress/hoeveel-slaap-heb-ik-nodig.php
(4): https://kce.fgov.be/sites/default/files/2021-11/KCE_330A_Obstructieve_slaapapneu_Synthese.pdf
(5): https://rhmagazine.be/nl/posts/preventie-van-slaapgebrek
(6): https://www.arbeidsveiligheid.net/sites/default/files/bijlagen/rapport-nachtwerk-fnv.pdf
(7): https://pubmed.ncbi.nlm.nih.gov/12003162/
(8): https://www.arbeidsveiligheid.net/sites/default/files/bijlagen/rapport-nachtwerk-fnv.pdf