The association between elderly people’s sedentary behaviors and their health-related quality of life: focusing on comparing the young-old and the old-old

Elderly people aged ≥65 years in South Korea constitute 13.8% of the total population, and this share is expected to increase to more than 40% by 2060 [1]. The interest in improving quality of life by improving the health of the elderly and preventing diseases is inevitably increasing because the increase in the elderly population results in increasing social costs. Health-related quality of life (HRQoL) refers to perceived physical and psychosocial health or well-being [2]. Recent evidence suggests that sedentary behavior is inversely associated with HRQoL [3].

Sedentary behavior is defined as any waking behavior characterized by low-energy expenditure while in a sitting or reclining posture [4]. It has been reported that longer durations of sedentary behavior lead to higher obesity, type-2 diabetes, reduced bone density, cardiovascular diseases, and mortality [5‐7]. Particularly in the case of elderly people, approximately 60% of their waking hours are spent sitting, and they are the group that has the longest durations of sedentary behavior [8].

A review of the literature on the influence of sedentary behavior on HRQoL indicated that high level of sedentary behavior is significantly related to low level of HRQoL, and some studies [9, 10] have indicated that reducing sedentary behavior significantly improves HRQoL. Research, however, has mostly been conducted on adolescents or adults, and investigation of the effect of sedentary behavior on people’s HRQoL over the age of 65 is limited. In particular, concerns have been raised [11] that studying elderly people with a wide age range (65–95 years of age) may lead to overlooking the differences in health status and problems between the young-old (aged 65–74 years) and the old-old (aged≥75 years). As evidence for the potentially neglected differences, the average healthcare cost of elderly people aged ≥75 years is almost twice as much as that of the young-old, and the old-old are significantly more physically, mentally, and financially vulnerable than the young-old [12]. Accordingly, Negarten, Moorn, and Low [13] proposed classifying the elderly under the age of 75 years as the young-old and those who are 75 years or older as the old-old. As recent studies have found that the average life expectancy has increased to 86 for men and 91 for women in the UK [14], there is a need to evaluate HRQoL, an indicator of the elderly aging process, separately for the young-old and the old-old [15]. Though some studies have verified the association between HRQoL and sedentary behaviors of the elderly [16], few studies have addressed the more refined characteristics of old age by distinguishing between the young-old and the old-old. To close this gap, the present study aimed to examine the association between sedentary behavior and HRQoL by classifying the elderly into the young-old and the old-old to assess whether sedentary behavior affected the two groups differently.

On average, participants spent 7.9 h/day in sedentary behaviors. Young-old spent 7.7 h/day on average while the old-old spent 9.0 h/day on average.

The major findings of the study can be summarized as follows. First, overall, participants spent 7.9 h/day in sedentary behaviors on average, with 7.7 h/day in the young-old, and 9.0 h/day in the old-old. This is longer compared with the reported average sitting time of 5.8 h/day in adults aged 18–65 years in 20 countries [19]. Although it seems somewhat shorter than the reported 8.5 h/day in elderly people in the U.S. [20], it is longer than 6.0 h/day in England [21] and 7.4 h/day in Spain [22]. One possible reason for the Korean elderly’s longer sitting time in comparison to their international peers is thought to be that more than 90% of the Korean elderly spend most of their leisure time watching TV or playing Korean games such as hawtu, baduk, and janggi, which are played sitting down at senior centers [23]. However, these sedentary social and cognitive activities are also related to the wellness of the elderly and low risk for dementia [24]. Therefore, future studies should not only consider the length of time spent sitting but also the social and cognitive activities performed during those sedentary periods. In addition, sedentary time of the elderly may differ according to country, with the possible influences of culture or ethnicity on the overall life habits of the elderly including sedentary behavior; however, cross-country analysis on the topic is rare. Some research has revealed the influence of environmental factors such as residential areas [25] including rural areas and cities, welfare facilities for the elderly [26], resting places [27], and housing structures [26] on sitting time of the elderly. Accordingly, further research needs to be conducted on environmental and cultural factors that influence the sedentary behavior of the elderly.

Second, the present study found that sedentary time is longer among the old-old than the young-old. This finding is consistent with previous research [8, 16], and Shiroma, Freedson, Trost, and Lee [28] also reported that as age increased by 1 year for elderly aged ≥65 years, total daily sedentary time per year increased by approximately 5%. This is due to the increased mobility impairment as aging progresses from young-old to old-old [25]. Compared to the young-old who are comparatively healthy, active, and independent, the old-old spend a long time sitting due to the fact that they are the age group to be most directly affected by mobility disorders resulting from chronic health issues such as arthritis and pain [29]. Therefore, interventions to minimize the number of chronic illnesses in the old-old who have mobility disorders are needed to ensure that the elderly people are healthy and able to maintain independent body functions. In addition, consistent management and implementation are necessary in promoting preventative programs that can prevent the development of diseases among the elderly people with chronic diseases.

Third, there were significant differences only in the pain/discomfort and anxiety/depression areas of quality of life between the effect of general characteristics on HRQoL in the young-old and the old-old. The young-old people had larger differences in quality of life relating to pain/discomfort based on gender and whether or not they were bedridden in comparison to the old-old. Additionally, there were significant differences in pain/discomfort and anxiety/depression due to marital status only in the young-old. Because the young-old often have jobs, pain/discomfort problems can have a bigger impact on the quality of life relating to financial activities and health [30]. In addition, the young-old have a higher chance to receive help, share emotions, allow financial help, and interact socially through their spouse which can have a positive impact on HRQoL such as lessening the anxiety, depression, and discomfort felt [31]. The reason that there were no significant differences in HRQoL relating to other general characteristics in the old-old could be that the old-old tend to find meaning in existence itself and adapt to and find joy in the current situation despite cognitive and functional limitations, financial situation, and isolation from society and family [32]. However, the research results on the quality of life differences due to general characteristics such as gender, financial situation, and existence of spouse between the young-old and the old-old are not consistent. Therefore, a more definitive study in the future is needed to identify the changes and affecting factors.

Fourth, the results of the current study show that daily sitting time in the elderly and the five sub-areas of HRQoL had a significant positive correlation. This is similar to other related studies on elderly people [16]. In particular, the current study found that the association between sedentary activity and HRQoL was stronger in the young-old than in the old-old. Also, in comparison to the young-old, the HRQoL areas of usual activities, anxiety/depression, and mobility were highly related to sedentary activity in the old-old. The reason behind these results may be that the old-old experience decreased mobility and increased cognitive problems such as dementia due to chronic illnesses, which may pose problems with usual activities and thus increase sedentary activities [32]. The results can also be explained by the fact that the decrease in mobility and cognitive functions have a direct effect on sedentary activities and self-efficacy, and self-efficacy in turn can exacerbate anxiety and depression and affect the psychological quality of life [33]. In addition, TV or computer usage which comprise a large portion of sedentary activities can hinder social relationships including reducing family time and thus can negatively affect the quality of life by increasing anxiety and depression [34]. Accordingly, in planning healthcare services for elderly with mobility difficulties, services meant to reduce sedentary behavior and maintain physical activities should be developed with consideration of the level of activities. In addition, sedentary time should be integrated into movement behavior guidelines for the elderly, who would benefit from sitting less, breaking up their sitting time, and moving more.

Lastly, comparisons between the young-old and the old-old indicated that the latter have higher odds of problems in all five dimensions of HRQoL with increase in sedentary time. On the other hand, the young-old had higher odds of self-care and usual activities problems, but no statistical significant influence on mobility, pain/discomfort, and anxiety/depression. The reason why sedentary time had no impact on mobility, pain/discomfort, and anxiety/depression of the young-old but affected the old-old may be that the young-old are relatively healthy, active, and living independently [35]. According to a study by Choi [36], only 7% of South Korean elderly aged between 65 and 74 need assistance in personal daily activities, but the proportion rapidly increases after age 75 years, with 40% or more of the old-old aged ≥85 years reported to be in a dependent state. Furthermore, factors such as chronic diseases, deterioration of financial situation, isolation from society and family, and cognitive impairment have been reported to cause depression with increase in age [32]. That is, the old-old are more prone to anxiety and depression due to increased sedentary behavior caused by activity limitations, which are aggravated by socioeconomic responsibilities, loss of independent functioning in everyday life, and alienation from family. Therefore, the old-old would have more accessibility to services if community-based health promotion programs offered activities to reduce sedentary behavior. This would be beneficial not only because of the old-old elderly’s lower education and socioeconomic levels compared to the young-old, but also due to their decrease in physical functioning. Accordingly, when visiting healthcare services are provided for the old-old with consideration of cohabiting family, services meant to reduce sedentary behavior and promote physical activities should be developed with consideration of the level of activities.

The results of the current research have revealed associations between sedentary activity and health-related areas of quality of life as the elderly get older. Therefore, it is necessary to identify influencing factors of the sedentary behavior of the elderly, develop intervention programs to reduce sedentary behavior, and strengthen welfare systems and policies for the elderly within the community. Research to confirm the effectiveness of these interventions and strategies is also needed. The present study is limited in that the causality among variables cannot be determined due to its cross-sectional design. In addition, sedentary behavior was measured by a self-reported questionnaire, rather than accurate measurements. Future research can obtain objective measurements using instruments such as accelerometers and compare results with the self-reported survey results. Longitudinal research is also needed to further investigate the health-related outcomes including quality of life measures by evaluating the length and social and cognitive aspects of each sedentary activity type. Furthermore, research is called for to identify the environmental and cultural factors that may affect the sedentary behavior of the elderly and to monitor causality of sedentary behavior and life quality for an extended period. Lastly, ongoing interventional studies are needed to improve health-related quality of life in relation to the sedentary behavior of the elderly.