VOL: 97, ISSUE: 36, PAGE NO: 40
Christopher Humm, MSc, BA, RGN, is a part-time staff nurse and writer
The importance of sleep to an individual’s physical and psychological well-being has been recognised for thousands of years. The English author Aldous Huxley (1894-1963) wrote: ‘That we are not much sicker and much madder than we are is due exclusively to that most blessing and blessed of all natural graces, sleep.’
Despite its importance, the formal study of sleep is a relatively new science. Although much research has been carried out over the past 40 years, precise theories about the mechanism, nature and function of sleep have proved elusive.
Research evidence suggests that sleep is induced by complex neurochemical mechanisms that occur in a number of brain structures and are mediated by neurotransmitters, including serotonin and noradrenaline. The function of sleep has given rise to a number of theories (Box 1).
Sleep is also influenced by circadian rhythms. These are innate cyclical rhythms that affect most human physiological systems, including hormone secretions and body temperature. There is evidence that the internal ‘body clock’ is situated in the brain area known as the suprachiasmatic nucleus (SCN).
The SCN receives information about the light-dark cycle from the retina and transmits it via the pineal gland to the body. The pineal gland secretes the hormone melatonin, normally during the hours of darkness. Melatonin is implicated in the control of the sleep-wake cycle, and when it is administered orally it enhances sleep. There is evidence that circulating melatonin concentrations decrease in old age and that the time of its secretion is delayed (Sharma et al, 1989).
The decrease in melatonin that occurs in older people appears to be associated with the weakening of circadian rhythms and an increase in sleep disturbance. It also calls into question the widely held belief that older people require less sleep. Perhaps it is the ability to sleep that diminishes in old age and not the need for sleep
The electroencephalograph (EEG), which measures the electrical activity of the brain, has clearly shown the existence of the stages of sleep (Box 2).
Sleep can be divided into two distinct electrophysiological states:
- Non-rapid eye movement;
- Rapid eye movement (REM).
REM sleep is characterised by rapid brain activity and is associated with dreaming. There is an autonomic response of rapid eye movement, fluctuating heart, respiratory and blood pressure rates and increased gastric secretions.
Arousal is difficult during REM sleep and it is believed that this is the stage where mental restoration occurs. If woken during REM sleep, 80% of people report they have been dreaming (Roth and Dement, 1989).
A person will normally go through the stages of sleep several times during the night. The cycle usually takes about 90 minutes, with the length of time spent in REM sleep increasing through each cycle. Stages three and four are prevalent during the first part of the night but become shorter as the night progresses. REM sleep increases later in the night.
The architecture of sleep changes with increasing age and studies of older people have revealed definite differences in EEG characteristics compared to other age groups. The main ones are:
- Less time spent in slow-wave sleep (the restorative component) and a decrease in the amplitude of the slow waves;
- A decreased number of eye movements during REM sleep, suggesting that it is less intense and that less time is spent in REM sleep;
- Increased frequency of daytime napping (25% of 70-year-olds nap compared with 45% of 80-year-olds);
- An increase in the number and duration of awakenings and a reduced arousal threshold for noise.
The changes in sleep patterns associated with advancing years are consistent with subjective complaints of sleep disturbance reported among older people (Swift and Shapiro, 1993). These include dissatisfaction with the quality of sleep and increased complaints of insomnia.
Disturbed or poor-quality sleep can have an adverse effect on other disorders and is characteristic of a number of physical and psychological complaints. Many medical conditions common to older people may also have an impact on sleep. Examples include rheumatism and arthritis, which cause pain, and nocturnal dyspnoea and angina, which may be caused by left-ventricular failure or nocturnal tachycardia. Bladder detrusor muscle instability or prostatism, both of which may cause nocturia, are age-related complaints, as are sleep apnoea, restless leg syndrome and night cramps (Swift and Shapiro, 1993).
There is evidence to support the theory that sleep aids the healing process, and the relationship between sleep and the immune system has been described as intimate (Dotto, 1990). When an individual is asleep, energy expenditure is reduced and the level of stored energy rises, leading to protein synthesis. There is also an established link between sleep and psychiatric disorders. Conditions such as anxiety, depression and dementia can have an adverse effect on sleep. For example, 90% of people with depression have some sleep abnormality (Crisp and Shapiro, 1993).
Complaints of insomnia must always be taken seriously, not only because they affect general well-being but also because they may be the first symptom of an underlying physical or psychiatric disorder.
Given the evidence, the role of the nurse in assessing, planning and implementing a care regime that maximises an older person’s opportunity to sleep becomes vitally important. A comprehensive night care plan is essential. It is important to take an accurate medical, psychological and social history, noting anything that may affect sleep. Information obtained from relatives can be useful as a resident could be experiencing negative emotions which he or she is reluctant to reveal.
A sleep history should be taken, including preferred bedtimes, usual time of sleeping and waking and the preferred time to get up.
Sleep environment is also important and residents should be given a choice of lighting, ventilation and bedlinen in their rooms.
Night-time in a nursing home can be lonely for residents, particularly in the weeks after admission. Staff should be aware of this and make time to discuss any fears residents may have.
Included in the night care plan should be details of preferred positions for sleeping and whether or not a resident is able to adjust his or her position during the night. Other ways to ensure sleep are to avoid alcohol and tobacco, particularly before bed, and increase daytime activity. There is evidence that exposure to bright light can strengthen natural circadian rhythms and enhance sleeping patterns.
Once a successful individual sleep routine has been established it should be maintained as it may strengthen the sleep-wake pattern, helping to minimise disruption.Creating the optimum individualised sleeping environment is the first and most important step in promoting healthy, drug-free sleep.
There is evidence that older people have an altered perception of sleep and can underestimate the amount of sleep they have had. As part of the sleep assessment, a record should be kept of the times that a resident goes to sleep, the length of time spent asleep (as well as the frequency and possible cause of any disturbances), and his or her usual waking time. Medical advice should be sought if sleep problems persist.
The management of staff workload associated with residents getting up in the morning is important. This may require a movement away from traditional practices and regimes where staff get all residents up and dressed early in the morning, regardless of their personal preference.The same applies to the time patients retire at night.
After lunch there is a postprandial dip in body temperature. This is a popular time for a nap and, again, establishing a routine may be helpful. When considering residents’ sleeping patterns, the importance of individuality cannot be overemphasised and staffing levels should be taken into account to ensure that residents are given any help they need when they need it.
There are many reasons for sleep disturbances in older people and accurate assessment ensures that problems are identified, enabling any treatment to be implemented. This article simply scratches the surface of a complex subject in which further research is required, research that could well be done by nurses.
Nursing is an activity that takes place over 24 hours and practitioners should be aware that their responsibilities do not stop when a client goes to bed at night.