Sleeping is a major component of health, and sleep disorders increase the risk of major diseases, including cardiovascular disease.¹⁾ A previous study reported associations between sleep disorder and heart failure, coronary heart disease, and irritable bowel syndrome.²⁾ Sleep problems are well known to affect the quality of life,³⁾ including poor response to health that indicates a decrease in subjective health perception. Furthermore, sleep disorders, including insomnia, daytime sleepiness,⁴⁾ short sleep duration, and long sleep duration,⁵⁾ are associated with decreases in subjective health perception. Sleep quality is also associated with decreased quality of life, including subjective health perception.⁶⁾

Subjective health perception involves recognizing one’s health status; this information can then be used to assess an individual’s general health status.⁷⁾ In addition, regardless of the actual state of health, if the subjective health perception is poor, the level of daily activity is low, which could negatively affect the state of wellbeing.⁸⁾

In contrast, it is well-known that sleep patterns change with age,¹⁾ that aging is a major cause of sleep disorders, and that various factors are related to sleep disorders in older adults.⁹⁾ They have decreased deep sleep, difficulty falling asleep, increased arousal while sleeping, and decreased total sleeping duration.¹⁰⁾ These observations suggest a high prevalence of sleep disorders in older adults.¹¹⁾ Thus, these individuals with a high prevalence of sleep problems may also have a high possibility of reduced subjective health perception, which may ultimately affect the actual health status.

This study assessed the relationship between sleep habits and subjective health perception rather than the quality of sleep and sleep disorders, which have been evaluated in previous studies. Sleep habits generally differ between weekdays and weekends. In most cases, weekend sleep duration is relatively longer, as reported by the Korean National Health and Nutrition Examination Survey (KNHANES),¹²⁾ and may do so even after retirement. Moreover, as older adults are more likely to live according to traditional gender roles, sleep habits may also differ according to sex. Thus, the purpose of this study was to clarify the association between sleep habits and subjective health status in older adults.

This study investigated the associations between sleep habits and subjective health perception. A previous study reported that sleep duration affected the quality of life at all ages, as assessed by the European Quality of Life-5 Dimensions (EQ-5D) index.¹⁴⁾ Inconsistent with the results of our study, previous studies reported an association between the quality of life and sleep patterns. However, previous studies also reported that responses to the EQ-5D were related to subjective health status.^15,16) This trend was expected to be prominent in older adults who often have an overall lower quality of sleep.¹¹⁾ We observed different associations between sleep habits and health perceptions between sexes in the present study.

In this study, weekday and weekend sleep durations were associated with subjective health perception in men but not in women. Subjective health perception is how an individual perceives his or her health, which may differ from their actual health. However, negative subjective health perceptions are associated with an increased prevalence of depression or stress-related symptoms;^17,18) thus, subjective health perception is considered an objective indicator of health.¹⁹⁾ In this study, men with sleep durations of 9 hours perceived their subjective health to be significantly compared that in men with 7 hours of sleep duration on both weekdays and weekends. However, compared to 7 hours of sleep duration, we observed no significant difference in subjective health perception for other sleep durations. Older adults have a higher prevalence of sleep disorders;^10,11) thus, the impact of insufficient sleep duration on subjective health perception could be greater in this population than in younger populations. In other words, if older adults perceive that they are lacking sleep, their subjective health perception is likely to be worse compared to those in younger populations.

Many factors affect positive subjective health perception; among these, a sleep duration that is not too long and not too short is important,⁵⁾ which is consistent with our results. However, subjective health perception was not related to sleeping or waking times in men in our study. Lifestyle determines sleeping or waking time, and these are considered insignificant if the sleep duration is sufficient.

In women, sleep duration, sleeping time, and waking time were not related to subjective health perception. The prevalence of sleep disorders is higher in older women than in older men.^20,21) Thus, sleep disorders may negatively affect the relationship between sleep habits and subjective health perception compared to that in individuals without sleep disorders. Therefore, sleep habits are unlikely to be a significant factor for subjective health perception in older women with sleep disorders. Also, sleep patterns of older women might be affected by both social and familial roles, meanwhile these in older men are more likely to be affected by only social roles, in Korean cultural perspective. Additionally, alterations in sleeping patterns may differ between older adult men and women. In older adult men, a lack of deep sleep is a major problem, while sleep latency was a predominant sleeping problem in older women.²²⁾ Consequently, insufficient sleep duration was related to poor subjective health perception in older men lacking deep sleep.

We observed associations between weekday and weekend sleep duration and subjective health perception in men. These results may inform the regulation of health policy in this population. Generally, 8 hours is considered a sufficient sleep duration in adults, although one study reported 7 hours to be sufficient.²³⁾ Older men with a lack of deep sleep may not perceive their subjective health to be high despite having a sufficient sleep duration (7–8 hours); in this study, those with 9 hours of sleep duration perceived their health to be good. Subjective health perception is not a substitute for actual health status but is helpful as an objective indicator to predict the actual health status.^24,25) Additionally, one study reported that poor perception of subjective health increased the risk of suicide and decreased daily life activities.^8,26) Thus, older men may not sleep enough due to sleep disorders, or if they did sleep, their sleep duration was less than 8 hours. Their subjective perception could also be deteriorating, leading to an increased risk of disease. Therefore, sleep duration should be assessed in the initial medical examinations of older men. If the sleep duration is insufficient, sleep hygiene should be managed or pharmacologic intervention should be considered. Further study is needed regarding the effects on older adult women.

This study has a few limitations. First, due to the cross-sectional design, the observed relationships established did not establish causality. Prospective studies are needed to clarify the causality of subjective health perception and sleep habits. Second, data on medical history and sleep patterns were obtained through a questionnaire; thus, missing variables or overstatement are possible. The question used to estimate sleep duration, “when do you usually go to bed and when do you wake up?” was very simple and might not reflect the average duration of sleep. Third, we analyzed only sleep habits as represented by sleep duration, sleeping time, and waking time, but not sleep quality, which was not considered is as important as sleep pattern. Despite these limitations, the strength of this study was that the study population may represent the Korean older population. Moreover, to our knowledge, this is the first study to assess the relationship between sleep habits and subjective health perception in this population.

In conclusion, weekday and weekend sleep durations were related to subjective health perception in older men. Additional studies are needed to determine how sleep habits, including sleep quality, affect the subjective health perception of older adults.