Is lack of sleep a killer?
It is well known that sleep affects general health, and a strong suspicion that it affects longevity too. Several studies have put this to the test.
One review was based on the general population, not a hospital or biased group. There were two studies reviewed, the The Busselton Health Study in Australia which is is a long-term and on-going health study of the relationship between sleep and pulmonary disease, diabetes and cancer. It is ongoing in Busselton in Western Australia.
The second report by Young and colleagues is from the highly publicized and productive Wisconsin Sleep Cohort. Part of the problem is that it’s not ethical to try some with and some without as sleep deprivation may be a fatal disease.
The Whitehall study (UK) showed that those who had cut their sleeping from 7h to 5 hours or less faced a 1.7 fold increased risk in mortality from all causes, and twice the increased risk of death from a cardiovascular problem in particular.
A 2010 paper, Mortality Associated with Short Sleep Duration: The Evidence, The Possible Mechanisms, and The Future discussed possible mechanisms – however it is clear that there is a relationship (even if only with motor vehicle accidents!)
As our society becomes a 24 hour affair, “open all hours” we must be mindful of the need for 7-8 hours quality of sleep per night and for most, “early to bed, early to rise – makes a man both wealthy and wise”.
Warning signs of sleep deprivation
Guidelines currently suggest healthy adults should aim for seven to eight hours of sleep each night. According to healthcare experts, sleep deprivation is defined as a failure to obtain sufficient total sleep and can have serious health consequences.
Sleep deprivation has a cumulative effect, and individuals vary in how little sleep it takes to feel sleep-deprived. For example, one person may feel sleep-deprived after six hours of sleep, and another might only feel sleep-deprived after two or three hours of sleep.
Sleep deprivation is associated with increased risks for obesity, type II diabetes, high blood pressure, and cardiovascular disease. Insufficient sleep weakens the immune system, and sleep-deprived patients do not respond as well to vaccines as individuals who have had sufficient sleep.
Sleep deprivation is also associated with kidney disease, stroke, and increased signs of skin aging. Patients struggling with sleep issues may want to see a sleep specialist for advice.
The specialist will ask about the patient’s sleep routines and sleeping environment, and the patient might be asked to participate in a sleep study to check for underlying medical conditions that could be affecting sleep quality and duration.
Yawning and fatigue
Yawning and fatigue may both signs of insufficient sleep, and these can occur after even just one night of poor sleep. For example, patients might find themselves yawning on their commute to work or at the office the next day, and they may yawn more frequently as the day progresses.
Fatigue can make patients feel groggy, and it is often difficult for patients to stay awake throughout work. After a night of poor sleep, it is common for individuals to feel like they need to take a nap during the day to catch up on sleep.
Both yawning and fatigue increase with each successive night of poor sleep, and fatigue is known to impair coordination. This could increase a patient’s risk for motor vehicle accidents, trips, and falls.
Patients who experience fatigue that is not relieved by a few nights of sufficient sleep should see a doctor to check for underlying health issues. While fatigued, patients might want to use public transportation if possible, although far better to determine and resolve the cause and it could also help to avoid operating heavy machinery during this time.
Forgetfulness
Sleep deprivation negatively impacts the brain, and this typically manifests as forgetfulness. Short-term, long-term, and working memory are all affected.
Sufficient sleep enables the brain to form connections that help the patient with information processing and retention. Sleep deprivation disturbs this process, and patients could notice they struggle with routine tasks as a result. For example, they might forget where they put their keys, have difficulty recalling words and completing sentences, or accidentally omit an ingredient from a recipe.
Studies have shown individuals who are dealing with sleep deprivation have to put in much more effort than others to complete basic verbal reasoning tasks, for example.
Forgetfulness associated with sleep deprivation usually improves if the patient starts to get sufficient sleep consistently. Patients who regularly struggle with forgetfulness even with sufficient sleep should have a neurologist evaluate their memory.
Moodiness
Those who experience sleep deprivation for a few nights typically display moodiness. They might be irritable, and they could overreact or become quick-tempered.
In addition, they could seem more troubled than usual by stressful situations, and they might have a lower threshold for what they define ‘stressful.’
Research indicates sleep-deprived individuals tend to report increases in negative moods such as anger, frustration, and sadness, and they also experience a decrease in positive feelings.
Chronic sleep deprivation over weeks, months, or years elevates an individual’s risk of developing clinical depression, anxiety disorders, and other mental health conditions.
Patients who experience moodiness after a night or two of insufficient sleep should try to take a nap if possible, and they may find that their mood returns to normal once they can catch up on sleep.
Individuals who are chronically sleep-deprived may need help from sleep specialists and mental health professionals to improve their sleep quality and treat their anxiety or depression.
Depressive symptoms
Lack of motivation is a frequent symptom of chronic sleep deprivation too – its difficult to strive when you’ve nothing left to give. Individuals might feel overwhelmed by even the simplest tasks at home or work, and they could feel unable to start a task at all.
This lack of motivation may progress to chronic procrastination, and patients could have poor work or school performance. Patients may not be able to focus on their goals, and it may seem impossible to even define their goals.
Lack of motivation is often seen in depressed patients, and sleep-deprived individuals who display this symptom or who have depression may also be more likely to engage in risk-taking, dangerous behaviour in the long term.
They are significantly more likely to experience suicidal thoughts. Individuals who struggle with motivation over a prolonged period may want to keep a journal to document their struggles, and it could also help to see a sleep specialist. Motivation may improve with sufficient sleep. If not medical review should be sought.
Inability to concentrate
Sleep deprivation is strongly linked to an inability to concentrate. The effects of sleep deprivation on an individual’s short-term memory make it hard for them to organize things, plan, or come up with creative solutions to problems.
Studies show sleep-deprived patients have shorter attention spans than those who are not sleep-deprived. Sleep deprivation causes individuals to be less alert, and patients often develop impairments in judgment and reasoning skills.
Decision making becomes challenging, and patients are easily confused. They are less able to correctly assess the risk associated with certain situations, and they might make poor choices as a result. Work evaluations, school grades, relationships, and family life could all suffer due to an inability to concentrate.
There is a known association between quality sleep deprivation and attention deficit hyperactivity disorder symptoms.
Patients who notice this symptom regularly may want to consider having a sleep study. For most individuals, concentration issues caused by a few nights of sleep deprivation will improve once they achieve adequate quality sleep.
This is true of children and the “Walmart Syndrome” where kids play up, but often due to sleep deprivation (in the UK it’s “Tesco syndrome”!)
SLEEP DURATION AND MORTALITY: THE FUTURE
Both short and long duration of sleep are significant predictors of death in prospective population studies yet many questions remain regarding the sleep-mortality relationship.
A better understanding the physiological/psychosocial connections between amount of sleep and shortened lifespan is critical. Simply documenting this relationship is no longer sufficient – we must explore possible mechanisms and pathways as well develop targeted interventions that can positively alter this relationship.
Research programs should investigate long and short sleep separately, as both are associated with increased mortality risk but the pathways may vary.
Therefore, increased research needs to phenotype habitual long and short sleepers, to better characterize these groups in terms of prospective and/or objective sleep, psychological functioning, performance, and health status, including obesity, cardiovascular functioning, glucose tolerance, etc.
Sleep quality should be considered more carefully in addition to simply sleep duration. Sleep duration alone is an insufficient measure for characterizing sleep. For example, short sleep is not the same as sleep insufficiency. Studying sleep disturbance, alone and with sleep duration, will better elucidate the public health implications of sleep.
Potential mechanisms and pathways to mortality should be explored and clarified. While this paper presents some evidence for some of these pathways, they need to be explored in greater detail.
As an example, studies exploring social determinants of sleep are necessary. Studies of attitudes and beliefs about sleep, passed through society, culture and family, will help clarify the components of a social-ecological model of sleep.
Additionally, studies of health outcomes such as obesity, cardiovascular disease, and metabolic dysregulation, associated with habitual sleep parameters (verified with objective methods) will clarify which health outcomes are truly associated with habitual sleep.
Individual variation in sleep duration needs must be better understood. For some, 7-8 hours appears insufficient, and for some, 7-8 hours appears excessive. There has been little consideration of individual differences regarding sleep duration preferences and how these preferences are related to health outcomes.
Current investigations into individual differences associated with susceptibility to sleep loss are beginning to clarify this issue.
Community-based intervention studies are needed to better understand mechanisms that underlie this relationship and reduce mortality risk. For example, one intervention could include increasing sleep time to prevent obesity. We are not aware of any intervention studies that show weight loss in response to changes in sleep behaviour, although there clearly are connections in neurotransmitter, physiologic functioning and behavioural response to sleep deprivation.
It is important to recognise that sleep deprivation is not only the result of not spending enough time in bed asleep, although clearly this is one reason. Anything affecting sleep quality (obstructive sleep apnea and snoring) or insomnia (physiological or emotional) will also cause the same effects and must therefore be screened for.
Conclusions – Does quality sleep help you live longer?
Statistical evidence supports that adequate sleep for that individual, which is 7-8 hours per night; provides the best chance of maximizing your longevity from a sleep standpoint. Studies indicate that sleep longer or shorter than this ‘ideal’ show a tendency toward a reduction in average longevity.
What can we do to sleep better and live longer?
