Reduce sitting and lying: What do we know and what requires further research?

As a result of technological developments during the past century, sitting time has increased dramatically. During the past decade, emerging evidence has shown that a vast amount of sitting time may be as dangerous as smoking, thus showing it to be an independent risk factor for several diseases. This also affects older people, and a recent study showed that sedentary time in older people increased the risk of dependency in daily activities [1]. Older people with reduced health and multi-morbidity are especially vulnerable to inactivity such as sitting and lying owing to a reduced reserve capacity. Studies have shown that leg muscle strength declines twice as quickly as arm muscle strength in older adults. In addition, muscle strength may be reduced with up to 5% per day during long-term bed-rest. Long-term bed-rest also leads to reduced heart capacity and reduced exercise tolerance. These factors are seldom taken into account when organizing care for older people in hospitals and nursing homes. One study has shown that older people who were inactive (mostly bed-rest) during a hospital stay had a six times higher risk of dependency in daily activities and of discharge to another institution, and 34 times higher risk of mortality independent of acute disease, multi-morbidity and demographic factors, compared to those who were active (walking independently on the ward once or twice a day) [2]. In addition, a meta-analysis showed that physical activity during hospital stay, in addition to ordinary care and rehabilitation, reduced the length of stay, the risk of discharge to another institution and the total healthcare costs [3].

We do know that people should be physically active for at least 30 min/day on 5 days/week, but we do not know how much we need to reduce inactivity in sitting and lying in older people to reduce the risk of further physical decline and health problems or to optimize a rehabilitation program. Furthermore, since technological developments in care for older people may lead to a further increase in sedentary behavior, this needs to be taken into consideration in future development and research studies. There are four major challenges that we need to address in the future: (i) to increase knowledge among health and social care workers of the benefits of physical activity and risk factors of inactivity; (ii) to increase and improve teamwork to enhance the care and rehabilitation processes; (iii) to conduct research into the amount of sitting time that poses challenges and increases the risk of further decline; (iv) and to consider the side-effects of technological developments related to care for older people.

The first challenge has been addressed by the EUropean Network for Action on Ageing and Physical Activity (EUNAAPA) by developing a curriculum for those working with older people [4]. The curriculum contains suggestions for topics that should be included in a course that can be given on different levels depending on the prior knowledge of the participants, and is based on the latest knowledge in the area. The second challenge is based on the first, but also needs to be addressed by policy makers, politicians, and health and social care managers when organizing care. The third challenge requires intervention studies with high methodological quality, but also studies developing and evaluating methods to measure inactivity in frail older people. In addition, the heterogeneity among the older population must be addressed in the design and analyses of the studies. The last challenge might be met by introducing measurement of side-effects (e.g. risk of increase in sedentary behavior) in studies concerning technological development and testing, as is already done in pharmacological studies.

Declaration of interest

The author reports no conflicts of interest.