Nurses commonly ask their patients whether they have slept well to ascertain if their sleep has been disrupted or is disordered. Indeed, the topic of sleep has recently attracted more attention with the realisation that it has a physiological function and that insufficient, as well excessive sleep, can have detrimental consequences for the individual. To date, research evidence suggests that sleep has a role in homeostasis, regulation of the endocrine and immune systems, clearance of neurotoxins, receptor turnover and aspects of cognition (memory, concentration, mood and performance) (Iranzo, 2022; Siegel, 2022).
An overview of systematic reviews published between 2008-2018, which included 4 437 101 participants from across 30 countries and reported on 14 outcomes (mortality, cardiovascular disease, type 2 diabetes, mental health, neurodegenerative disease, cognitive function, falls, accidents/injuries, obesity, biomarkers of cardiometabolic risk, bone health, health-related quality of life, work productivity and physical activity) found that the dose-response curves showed that sleep duration of 7-8 hours per day were most associated with health among adults and older adults (Chaput at el, 2020). The effect of age was not apparent.
‘Circadian rhythms reflect molecular oscillators in the brain, which interact with behavioural and environmental cycles promoting sleep during night time. However, environmental changes such as work, social schedules and light exposure may cause disturbance of ‘normal’ cycles.’
A systematic review of 34 studies undertaken in the Netherlands (200 358 participants), the UK (471 759 participants) and the US (409 617 participants) found that adults (≥18 years) reported a mean of 7.8 hours (± 0.9 hours) in bed and a total sleep time of 7.1 hours (±1.0 hours) (Kocevska et al, 2021). While 24.5% of the population in this review reported sleeping less than the recommended sleep duration for their age, less than 10% of adults in all three countries reported sleep duration outside of the ‘acceptable’ ranges. Sleep efficiency (total time asleep while in bed) appeared to decline into adulthood, although 25% of those over 65 years reported sleeping over 95% of their time in bed. Adult women reported a longer total sleep time (P<0.001) and a marginally lower sleep efficiency (P<0.001) than men. Poor sleep quality was most prevalent among adults spending 6 hours or less in bed and difficulty getting off to sleep was most commonly reported by those spending 9 hours or more in bed. Women were more likely to report symptoms of insomnia irrespective of age compared to men (difficulty getting off to sleep, difficulty maintaining sleep, early morning awakening P<0.001). Women also appeared to use more sleep medication (P<0.001) but snoring was more common in men (P<0.001), although the gender difference narrowed in older ages. Being overweight/obese (obesity is a risk factor for obstructive sleep apnoea) and smoking were associated with shorter total sleep time and may indicate health consequences of less sleep. It is worth noting that there are consistent differences between objective (actigraph) and subjective (diaries and other forms of self-report) data but subjective data are the main source of clinical data and also reflect perceptions of sleep patterns and sleep associated well-being.
Our lives are characterised by a daily rhythm, occurring over 24 hours and alternating between periods of sleep and wakefulness. Circadian rhythms reflect molecular oscillators in the brain, which interact with behavioural and environmental cycles promoting sleep during night time. However, environmental changes such as work, social schedules and light exposure may cause disturbance of ‘normal’ cycles (Meyer et al, 2022). Circadian disturbance is increasingly implicated in the development of a broad range of poor health outcomes such as cardiovascular disease, metabolic diseases, cancer, mood and cognitive dysfunction. Disturbance of normal sleep pattern may not be due to a change in circadian rhythms, but, for example, a disturbance in an aspect of work or social life, sleep-wake disturbance (insomnia, excessive daytime sleepiness, or both), or medical, psychiatric or other sleep disorders. However, a chronic sleep disturbance (if the symptoms have persisted for more than 3 months) may be caused primarily by a change in the circadian system or a lack of alignment between the endogenous rhythm and the desired sleep-wake pattern. The circadian rhythm is the central pacemaker for the human body (Meyer et al, 2022) and provides an escalating signal throughout the biological day, reaching a peak during the wake maintenance zone. In healthy individuals this occurs between approximately 19:00–22:00 hours, after which, the wake-promoting signal rapidly reduces and is accompanied by melatonin release and decreasing body temperature (sleep gate). The circadian wake-promoting signal is at its strongest 2 hours before habitual wake time, coinciding with the lowest core body temperature and cortisol peak. The circadian system also impacts sleep structure so that rapid eye movement (REM) sleep is highest shortly after the lowest core body temperature, and just prior to the cortisol peak. The body's circadian rhythm has a sustaining function, supporting essential physiological and biological processes across a 24-hour cycle. The circadian system and associated physiological rhythms are disrupted by night and some shift working; some individuals can find adaptation of their circadian rhythm very challenging. The Horne-Ostberg (1976) Morning-Eveningness questionnaire measures preferred timing of activities and sleep (i.e. diurnal preference or chronotype), although wearable technologies are increasingly ubiquitous as an alternative to understanding diurnal rhythms.
A variant of insomnia is a delayed sleep-wake disorder when an individual has difficulty falling asleep at a socially appropriate time and struggles to wake when required. This has a prevalence of 0·17–1·53%, decreasing to 0.7% in 40–64 year olds (Meyer et al, 2022). Although the underlying causes are unknown, it has been suggested that it may be related to a delayed opening of the sleep gate. Advanced sleep-wake phase disorder describes difficulty staying awake in the evening and waking very early in the morning and appears to have a very low prevalence (0.04–0.25%), although it is more common in older people and those with dementia (Meyer et al, 2022).
Insomnia is very prevalent, occurring in up to 50% of primary care patients, both independently and alongside other medical or mental health disorders (Perlis et al, 2022). It is also a risk factor in the development or exacerbation of medical and mental health disorders. It is often associated with a range of day time symptoms including fatigue, sleepiness, body aches, mood disturbance, changes in cognition as well as concerns about sleep. Cognitive behavioural therapy (CBT) is the first line of treatment and comprises four foci: stimulus control (restriction of stimuli in the bedroom); sleep restriction (limit time in bed/sleep rescheduling); sleep hygiene (principles of good sleep heath, including regular bed times); and cognitive therapy (reassessment of sleep-related beliefs to reduce sleep worry and related effort) (Perlis et al, 2022). Some CBT programmes also include relaxation or mindfulness training. The trials of CBT to treat insomnia indicate good outcomes up to 24 months. There are pharmacological treatments but they have side-effects and outcomes do not continue when treatment ceases. Treating insomnia where possible makes sense because it is debilitating for the individual and it also has a negative impact upon health and the ability to work effectively (Perlis et al, 2022).
Sleep problems are more common in older people partly because there are age-related changes to sleep (Suzuki et al, 2017). Older people also have more medical disorders, which include: pain; cardiovascular disease; pulmonary disease; gastrointestinal disorders such as constipation; urinary disorders such as incontinence; neurological disorders such as restless leg syndrome; Parkinson's Disease; and mental health disorders including anxiety and depression; all of which may disrupt sleep. Additionally, older people may take daytime naps, go to bed too early, use their bed for other activities such as watching TV, are lonely especially after the loss of a partner, or their medications may be psychostimulants. Good sleep hygiene alongside stimulus control and sleep restriction are recommended before the introduction of pharmacological treatments (Suzuki et al, 2017). Supporting older people to have sufficient sleep is important because the evidence suggests both very short sleep duration (<4 hours) and long sleep (>9 hours; may be an indicator of physical inactivity and loss of muscle mass) are associated with increased risk of falls (Yoshimoto et al, 2021; Goksu, 2023).
Sleep is increasingly attracting both clinical and research interest. The evidence indicates that sleeping an adequate number of hours in a regular pattern is essential for good health. Lack of sleep is not only associated with poor well-being and, when in work adequate sleep is essential for both productivity and safe behaviours, including driving cars safely. Perhaps today's lifestyles do not sufficiently promote good sleep behaviours and as community nurses, we can help our clients, their carers and their families re-set their sleep behaviours.