Dr Darren Mansfield
MBBS, FRACP, FJFICM, PhD
Director Epworth Sleep Centre
Self reported sleep disturbances are common among peri and post menopausal women. In a British population based study of 1498 women, the odds ratio for self reported sleep disturbance was 3.4 for post menopausal compared to premenopausal women; and 1.5 for peri versus pre menopausal women(1). However, among women presenting to a menopause clinic, where symptoms of menopause are likely to be substantially higher than in the general community of age matched women, the prevalence of self reported disturbed sleep is as high as 77%.
A number of other population based studies examining the association between menopause and sleep disturbance have shown that the link between menopause and sleep disturbance disappears when controlling for confounding influence such as age, socio-economic status and depression. However the more recent Wisconsin sleep cohort study(2) has provided the largest sample size of pre and post menopausal women with a cross sectional analysis of both subjective and objective sleep disturbance. In a sample population of 589 women in which confounding influences were carefully controlled for, the odds ratio of overall dissatisfaction with sleep among postmenopausal women was 2.2 when compared with premenopausal women. Although one would predict the high rate of disturbed sleep among patients attending menopause clinics to be related directly to menopausal symptoms, in particular vasomotor symptoms, no clear relationship between specific menopausal symptoms and disturbed sleep was observed in this study.
The Wisconsin sleep cohort study examined objective measures of sleep with single night polysomnography. No relationship with self reported sleep disturbance was identified. In fact a trend toward improved objective sleep measures was seen in post menopausal women for parameters such as total sleep time, sleep efficiency (percent of time asleep for the time in bed) and percentage of overall sleep in slow wave (deep) sleep. The subgroup of post menopausal women on hormone replacement therapy did not appear to differ in self report of disturbed sleep or objective measures of sleep quality.
The explanation for the discrepancy between self reported sleep disturbance and objective measures of sleep quality is not forthcoming. The lack of significant correlation for vasomotor symptoms and self reported disturbed sleep, points to the answer that a causal relationship between menopause and disturbed sleep may not be common. At the very least, assumption has led this relationship to be overstated.
One must therefore have some understanding of common causes of sleep disturbance to ensure an underlying sleep disorder unrelated to the menopause is not overlooked. This requires one to be able to take a brief sleep history and be familiar with practices likely in impact on sleep quality.
Sleep hygiene refers to the impact of lifestyle on sleep quality.
Stimulants and sedatives. Ingestion of stimulants such as caffeine, even in small quantities (two coffees per day) are capable of influencing objective measures of sleep. Other stimulants such as nicotine are also important as is the enquiry about illicit drugs. Sedatives including alcohol, prescription hypnotics and many antidepressants may increase duration of sleep but may adversely affect sleep quality by diminishing slow wave and rapid eye movement (REM) sleep.
Naps. A napping history is important to elicit. Brief naps of the order of 10-15 minutes do not adversely affect sleep quality or duration when taken around periods of circadian sleepiness (ie 10am and 2pm). In some patients with daytime sleepiness, naps of this nature are encouraged. Naps of greater duration or later into the evening (later than 6.00pm) impact on overnight sleep quality and are best avoided.
Sleep wake cycle. A well reinforced sleep wake cycle is an important part of sleep hygiene. It is encouraged that people with sleep difficulties go to bed and arise at similar times each day. People who are prone to sleeping in are more prone to sleep difficulties. The most commonly presented example is sleep difficulties among shift workers which are common and not easily overcome if lifestyle modifications are constrained by the occupation.
Determining sleep requirements. Ensuring patients get enough sleep is an important part of assessing sleep hygiene. Yet patients rarely present with symptoms of sleep deprivation due to excessive work related or social commitments affecting sleep duration without the patient being unable to self diagnose this. However some patients require less than average sleep yet try to follow social norms for going to and getting out of bed (eg 10.30pm to 6.30am). As individuals age sleep requirements fall yet social habits often mean that time in bed does not alter. This can allow sleep to disintegrate with the patient complaining of waking repeatedly over night. Sleep restriction protocols instigated by a sleep therapist can be very helpful in this group.
Exercise. Although exercise has not been rigorously studied, evidence suggests that sleep quality and duration can be improved by regular vigorous exercise. Sleep onset is associated with a fall in body temperature. One theoretical benefit of evening exercise is that the rise during, and subsequent fall in body temperature may facilitate sleep onset. Hot showers before bed may provide a similar potential effect.
Psychophysiological insomnia syndromes. This is one of the most common forms of insomnia. As the name implies, there is a psychological basis to this disorder. In this group of patients, difficulty with sleep onset or maintenance is conditioned or "learned" following an initial destabilizing influence on sleep. Patients often report fatigue the following day however daytime sleepiness is less common. Patients usually report that they previously slept well prior to a specific incident or period in their life. Although there may be psychological recovery from the initiating event, poor sleep persists through conditioning and is propagated by negative thoughts about sleep, frustration at the inability to sleep and consequent high anxiety states. Patients may respond to direct psychological strategies such as relaxation techniques and cognitive behavioral therapy. Clinical psychologists with specific interest in sleep disorders are the most appropriate choice of referral.
Phase shift insomnia. This is a disturbance of the circadian rhythm leading to sleep onset and offset being inappropriately timed. Delayed sleep phase presents with either a description of sleep onset insomnia or inability to get out of bed at the appropriate time in the morning, or both. This syndrome can be separated from other causes of sleep onset insomnia by enquiring about the preferred sleep onset and waking times. Exposure to appropriate timed bright light in the morning can effectively push sleep onset forward and overcome the problem. Melatonin may also alter the circadian rhythm although is less efficacious than light. Advanced sleep phase is less common and frequently associated with depression. Patients describe becoming sleepy in the evening associated with early morning wakefulness. Evening bright light can push back the sleep wake cycle and if necessary therapy for underlying depression may help.
Disorders of sleep fragmentation. Sleep apnoea is a condition of repetitive occlusion of the upper airway during sleep. Stereotypically it is a male predominating disorder although increasingly it is recognized to be prevalent among post menopausal women. A history of snoring or witnessed apnoeas by others is suggestive of the disorder although accounts of the patient and witnesses are often not reliable. Some patients complain of frequent wakening during the night but in contrast to the insomnia syndromes daytime sleepiness is common. Enquiry of sleepiness should mostly be directed to passive situations such as reading, watching TV, meetings or seminars, going to the movies or driving a car. Sleepiness usually must be very severe before active situations produce sleepiness. An overnight polysomnography is usually required to establish the diagnosis of sleep apnoea.
Summary. Although the perception of sleep deteriorates around the menopausal transition there is no clear evidence of a causal explanation for this and objective measures of sleep quality are generally not impaired. In response to complaints of disturbed sleep in this group of women a more intensive search for an underlying sleep disorder is required, rather than assuming it is a feature of menopausal symptomatology per se.. Also, it is important to recognize that HT may not ameliorate sleep disturbance.
References:
1. Kuh DL, Wasorth M, Hardy R. 1997. Womens's health in midlife: the influences of the menopause, social factors and health in earlier life. Br J Obstet Gynaeco 104;923-33
2. Young T, Rabago D, Zgierska A, Austin D, Finn L. 2003. Objective and subjective sleep quality in premenopausal, perimenopausal and postmenopausal women in the Wisconsin Sleep Cohort Study 26; 667-72
Content Updated July, 2006
