“How does Austria sleep?” self-reported sleep habits and complaints in an online survey

Especially in Western societies, an increasingly high number of people complain about sleep problems. Among clinically relevant sleep disorders, insomnia, which is characterized by problems initiating and maintaining sleep and the feeling of sleep not being restorative, is extremely prevalent. Subjectively, patients suffer from significant distress or impairment in social, occupational or other important areas of daytime functioning. Globally, insomnia is the most commonly reported sleep problem in industrialized countries [1], and numbers seem to have been increasing steadily during the past years [2]. Epidemiological research suggests that its prevalence is between 10 and 35% in the general adult population [3‐6]. Besides subjective suffering, sleep problems are also associated with a significant economic burden resulting from high direct (i.e. due to health-care consultations and treatment) and indirect (i.e. due to absenteeism and loss of productivity) costs [7, 8]. For these numbers to be translated into adequate health-care strategies, it is essential to know about the situation in a specific country. While a study from the Robert Koch Institute [9] presents data from 2010 on the situation among the adult population in Germany, the last appraisal from Austria dates back to 2007 [10]. However, especially given the reported increase in sleep problems during the last years, these numbers are likely to be outdated. Therefore, we opened a web-based survey in March 2018 to obtain a precise appraisal of the sleep quality and sleep habits of the Austrian population. We here present the results of the survey, in which 986 people had participated as of May 2019.

The “How does Austria sleep?” survey provides important insights into sleep behaviour and sleep problems in a convenience sample from the Austrian population in 2018/2019. While general sleep parameters such as sleep duration generally seem to be in line with what has been reported in a previous study [10], we identify an alarmingly high number of participants with sleep problems in a relatively young sample with an above-average educational level. Moreover, these sleep problems are in many cases chronic suggesting that the available treatment options may not be adequate.

In more detail, in this online survey, 73.4% of the respondents reported an average sleep duration between 6 and 8 h per night and 52.4% between 7 and 9 h. However, 46.5% also report that they usually sleep less than 7 h. This suggests that, in this sample, the average sleep duration is comparable to what has previously been reported by Zeitlhofer and colleagues in 2007 [10], although a substantial number of participants also does not sleep enough according to expert recommendations [19]. Generally, a sleep duration between 7 and 9 h has been recommended for adults [19], while short (< 6 h) and long (> 9 h) sleep has been associated with increased mortality and morbidity [20, 21]. Although it is still unclear whether there might be a causal relationship between long sleep duration and mortality, it seems more likely that people who sleep unusually long suffer from chronic diseases or disorders such as sleep apnea resulting in non-restorative sleep [22‐24].

Regarding sleep problems, 45.8% of the sample reported that they currently suffered from sleep problems. The results from the PSQI, a valid and reliable tool to identify sleep disorders, paint an even more alarming picture with only 31% of the participants being identified as “good sleepers”, 41% as “poor sleepers” and 28% even reporting severe sleep problems. More specifically, 23% of the sample reported problems falling asleep, 24% indicated they suffered from early awakenings, and 32% had problems maintaining sleep. A recent but still unpublished study from the Medical University of Vienna [25] suggests a considerable increase in the prevalence of sleep problems compared to the data from 2007, when only 6% reported problems initiating sleep, 9% complained about early awakenings and 26% reported problems maintaining sleep [10]. Although the present sample cannot be compared to these findings directly, it should be noted that the sample in the present survey was rather young (average of 40.9 years; 59.5% < 46 years) and well-educated with a presumably good socioeconomic status (51% academics, 26% higher education). This reflects a combination of characteristics that is usually associated with a decreased risk for sleep problems [26]. Besides this, in our sample, 86% of the respondents indicated they had been suffering from sleep problems for more than 6 months, and an unacceptably high number of 37% had even been suffering for more than 5 years. A possible reason for the high prevalence of sleep disorders could be the subjectively perceived burden. Indeed, approximately 57% of our sample felt burdened, and this was correlated with sleep problems (burdened “yes” vs. “no”, sleep problems “yes” vs. “no”; χ²(1) = 70.96, p < .001). The apparent focus on work-related demands may also have arisen from the fact that the sample was, on average, highly educated with 51% holding a university degree. More specifically, a high educational level often comes with more degrees of freedom and responsibility at work, which may increase perceived strain. For university students, several recent studies have emphasized that they are a highly burdened group at risk for (mental) health problems [27]. Another reason for sleep problems could also be irregular sleep-wake cycles. This effect was only statistically significant in young participants below the age of 30 though.

Besides sleep habits and sleep complaints, we also sought to investigate the use of electronic devices such as smart phones, laptops and e-readers before sleep. Here, 44% indicated they used a device until just before switching off the lights to sleep, and 20% switched it off just between 5 and 10 min before sleep. Critically, on the one hand, it has been suggested that the high proportions of short-wavelength light (i.e. in the “blue” range) of light-emitting diode (LED) screens may be detrimental for sleep by suppressing melatonin and increasing alertness [28‐30]. On the other hand, it may also be psychological features such as the entertaining and emotionally arousing character of electronic devices that are responsible for the negative effects. The extent to which each of these factors contribute is still unknown.

Last, we were also interested in the opinion of the people living in Austria on clock change, which the EU parliament wishes to abolish in 2020. In our sample, 58% would abolish clock change, and, of these, 57.8% would favour perennial daylight-saving or “summer” time (DST). While this slight preference for DST is in line with results from a non-representative EU-wide survey from 2018 [31], the number of those in favour of abolishing clock change was considerably higher in the EU survey compared to ours (i.e. 84% in the EU survey vs. 58% in ours). This may be due to self-selection with a very specific survey such as the one initiated by the EU particularly attracting participants who have a strong opinion on a topic. Interestingly, when we asked how much they suffered from clock change, 76% of our respondents indicated they did not at all or only slightly suffer from clock change. About 69% said they adapt immediately (38%) or within 1–2 days (31%) to the new clock time, and another 21% said they adapt within 3–5 days. This is well in line with the normal adaptation times of the circadian system to trans meridian travel, i.e. one time zone per day as a rule of thumb [32], and suggests that clock change may be less of a burden for many people compared to the impression generated in public debates.

One limitation of the study is that the sample, in contrast to the study by Zeitlhofer and colleagues [10], was not a representative for the Austrian population. In particular, the educational level was above average and a disproportionately high number of women participated in the study. However, in online surveys, representativeness is more difficult to obtain than in studies using face-to-face interviews due to mechanisms of self-selection. This may, unintendedly, also have led to good sleepers generally being less interested in participating in the study resulting in an overrepresentation of participants with sleep problems. Therefore, current efforts aim at inviting currently underrepresented parts of the population to this ongoing survey, for example, in the context of public-relations activities of the Salzburg sleep laboratory and articles in the lay press.

In conclusion, sleep duration was sufficient in about 50% of the respondents but insufficient (i.e. habitually less than 7 h) in 47%. Generally, sleep duration is therefore comparable to what has been reported in 2007 [10]. However, it is unclear to what extent this is a specific characteristic of the present sample. On a less positive note, the prevalence of sleep problems is alarmingly high, even in a sample that would usually be expected to be less prone to sleep problems. The persistence of sleep complaints for an unacceptably long time suggests that the current treatment options are either ineffective or, more probably, not used by patients. This may, for example, be due to limited capacities of sleep laboratories or patients not being satisfied with the options offered to them, which is often sleep medication, although the first-line treatment should be cognitive-behavioural therapy for insomnia [CBT-I; 33]. Other reasons may be that patients do not recognize their condition’s pathological significance, or patients simply not knowing where to seek help. Besides increasing the availability of effective low-threshold therapeutic options, psychoeducational approaches should aim at increasing the sensitivity of the population regarding the detrimental effects of, for example, the use of electronic devices just before sleep.