The effect of Active Plus, a computer-tailored physical activity intervention, on cognitive functioning of elderly people with chronic illness(es) – study protocol for a randomized controlled trial

Chronic illnesses in elderly people have a major impact on society. The older a person becomes, the more likely they develop one or more chronic illnesses, such as cardiovascular disease, osteoarthritis and diabetes [1‐4]. These chronic illnesses are associated with, among others, depressive symptoms, cognitive functioning problems, and mobility limitations [5‐7]. Eighty percent of the elderly population living in developed countries suffer from a chronic illness and 50–75% have to deal with multiple chronic illnesses [4, 8, 9]. Therefore, the demand for healthcare among elderly people is large and will increase even further in the future due to the aging world population [3]. Most countries experience growth in the number and proportion of older people in their population. The number of people aged 65 years or over is expected to nearly triple by 2050, rising from 542 million globally in 2010 to about 1.5 billion in 2050 [10]. More importantly, worldwide the population aged 60 or over is growing faster than all younger age groups. Since the number of elderly people increases and the potential labor force remains the same or even declines, the costs of health care will increase [11].

Chronic illnesses in the elderly not only have a major impact on society, but also on their individual degree of independence and quality of life [12]. Elderly people may suffer not so much from the illnesses themselves, but from the limitations as a result of these chronic illnesses [13]. These limitations, such as mobility restrictions, stand in the way of an independent life and can lead to loneliness [14]. Consequently, the World Health Organization [15] focuses its policy framework on active aging by which chronic illnesses and reduced mobility should be prevented on the one hand, and vitality, self-reliance, participation in society and quality of life should be optimized on the other hand [3]. This should culminate in elderly people living independently for as long as possible; and good health is a prerequisite for this [16]. The functioning of the elderly can be optimized by a change in lifestyle, of which physical activity (PA) is an important component [3].

Engaging in regular PA has great health benefits [17]. It is effective in controlling weight, strengthening muscles and bones, improving mood and the ability to do daily activities and preventing falls. Additionally, there is indisputable evidence of the effectiveness of regular PA in the prevention of several chronic diseases (e.g., cardiovascular disease, diabetes, cancer, hypertension, obesity, depression and osteoporosis) and premature death [18].

Furthermore, there is preliminary evidence to suggest that PA is beneficial for cognitive functioning (CF). An increasing number of scientific studies show that PA has a positive influence on CF in general [19]. However, not all PA programs show this result [20, 21]. In the aging brain, sufficient PA correlates with a reduced risk for cognitive decline [22]. Several review articles state that executive functions appear to benefit most from PA [23‐25]. Executive functions are higher-order cognitive processes that are necessary to control cognitive behavior. These processes include planning, working memory, inhibition, mental flexibility, as well as the initiation and monitoring of action [26]. Without these functions, well-organized behavior is not possible. However, the underlying mechanisms on how PA may protect against cognitive decline are still somewhat unclear, although elevated neurotrophin levels, improved vascularization, facilitation of synaptogenesis, decreased systemic inflammation, and reduced disordered protein deposition may play a role [19]. Studies have shown that adding any moderate intensity PA program in later adulthood is beneficial for cognitive performance, especially for very sedentary older adults [27]. All things considered, by engaging in regular PA, one can therefore actively contribute to a healthy brain.

Notwithstanding the increasing body of evidence for the importance of regular PA, most elderly people do not reach the recommended guidelines [28]. These guidelines state that adults should be active for at least 150 min at a moderate-intensity spread over a few days per week and perform resistance training at least 2 days per week. Data from the U.S. Department of Health and Human Services indicate that more than 80% of adults do not meet these guidelines for both aerobic and muscle-strengthening activities [29]. Comparable numbers are shown in a study in the Dutch population; only 33% of the elderly of 65 years or over meet the guidelines [30].

Within the elderly population those with chronic illnesses are most sedentary and perceive many PA related barriers [31]. Although a few PA programs exist for elderly with chronic illnesses (e.g. Coach2Move [32], Strong-for-Life [33], Life-P [34]) most programs are not easily accessible, often not attended by elderly with chronic illnesses and often only reaching already active elderly [35]. Moreover, the programs are often face-to-face and high demanding [36].

Active Plus is an existing proven effective personalized PA program for elderly people which provides the target group with 3 personalized PA advices (online and print delivered) in 4 months [37]. Preceded by a questionnaire (e.g. on current PA and perceived PA beliefs and barriers) a computer-tailoring program generates personalized advice, tips and exercises that are sent to the user. Active Plus raises awareness of PA, and guides PA initiation and maintenance. The program is tailored to patient and disease specific situations and needs [38]. Previous research in a general population of people aged over 50 years showed in the Active Plus group in 1.5 h per week more moderate to vigorous intensity PA after 1 year compared to controls [37, 39, 40], even in elderly people with limited mobility [41, 42]. Active Plus is highly cost-effective, reduces disease incidence and potentially reaches many elderly people with a chronic illness and limited mobility at very low costs [43‐45].

As the program Active Plus has strong indications for long-term effects on moderate to vigorous PA in the elderly with chronic illnesses and limited mobility, we hypothesize that Active Plus improves cognitive functioning in this target group. In a meta-analysis and systematic review on effects of exercise on cognitive function in chronic disease patients by Cai [46] a positive overall effect of exercise interventions on cognitive function was found. However, 22 out of 35 included studies only included patients with Alzheimer’s disease or Mild Cognitive Impairment. Other included studies targeted their intervention to only one individual chronic illness (i.e. cancer, heart failure). To our knowledge, the effects of PA on CF in an elderly population which suffers from a broad range of chronic illness(es) have not yet been tested. Furthermore, the interventions included in the meta-analysis were site-situated, which is high demanding, more expensive, and mainly focused on exercise, while a computer-tailored PA intervention like Active Plus has a strong focus on stimulating daily PA [35, 36]. Therefore, the primary objective of the present Active Plus study is to investigate the short-term (6 months) and long-term (12 months) effects of the Active Plus program on CF of people aged 65 years or older with chronic illness(es) through a clustered randomized controlled intervention trial (RCT). This paper describes the protocol for this objective and the other objectives below.

PA is complex behavior consisting of type of activity, duration, frequency, and intensity [47]. There are some indications that the beneficial effects of PA on CF are independent of these characteristics of PA [46]. However, another meta-analysis [48] showed that only a duration of > 45 min to ≤60 min per session at a moderate-to-vigorous intensity on as many days per week was beneficial for CF. Therefore, it is unclear what characteristics PA should have to be effective on CF in clinical practice. To provide more insight in this matter, we will study as another primary objective the relationship between the necessary type, frequency, duration and intensity of PA to increase CF or slow down its decline in the elderly with chronic illness(es) (ECI). To test PA behavior, we use both self-report questionnaires and accelerometers. Self-report questionnaires are known for overestimating PA, however they measure different constructs than accelerometers [49]. Therefore, both ways of measuring PA are administered in this project.

As mentioned before, elderly people with chronic illnesses have a lesser individual degree of independence and quality of life [12], and experience more feelings of loneliness [14]. Sufficient levels of PA and CF are important for self-reliance and a good health related quality of life (HRQoL) [3]. However, being sufficiently physically active is a great challenge for this target group [31]. Therefore, a secondary objective is to study the effects of the Active Plus intervention on self-reliance, HRQoL and loneliness.

To our knowledge, this is the first study that will investigate the effectiveness of an online computer tailored PA program on CF in people aged 65 years or older who suffer from a broad range of chronic illness(es). Until now, most research on the effects of PA on CF is done with people who suffer from one specific chronic illness and results are equivocal [46]. However, the population of people aged over 65 often suffer from a broad range of chronic illnesses and often have more than one illness [9]. Therefore, the results of this study are expected to be more generalizable to the general elderly population than previous research.

The Active Plus intervention stimulates PA in daily life and takes place in a real life setting. We already know Active Plus is effective in preventing the development of somatic diseases (e.g. diabetes) [43]. The effects on CF of such an easily accessible program that focusses on PA in daily life are not tested yet, as opposed to strenuous exercise programs that are site-based. However, such programs would be very beneficial to broadly reach elderly with chronic illness(es). Until now, the interventions used to investigate the effect of PA on CF in elderly with chronic illness(es) are often intensive site-situated [35, 36]. It is unmanageable and financially unaffordable to approach the complete target group with intensive face-to-face programs [35, 36]. Active Plus would potentially be a very cost effective solution [43‐45].

This study will not assess effects longer than 1 year after the baseline measurement and start of the intervention due to practical implications. However, it might be that cognitive effects of Active Plus are only visible after a longer timeframe, because it improves the cognitive reserve capacity and in this way prevents cognitive decline over a longer time. Nonetheless, other studies showed intervention effects on CF already after 6–12 months [19].

A great strength of this study is that the change in PA is measured both objectively with an accelerometer and with a self-report questionnaire. Questionnaires provide detailed insight regarding type of PA (e.g. household PA, leisure time PA), frequency and duration of specific PA behaviors. Such specific information is useful in targeting PA interventions and cannot be obtained from accelerometers. However, self-report PA questionnaires are known for their overestimation of PA which might occur due to misclassification of activities, double reporting, recall bias, and social desirability [74]. Accelerometers measure the quantity and intensity of movement. Although accelerometers result in objective PA measurements, they also have their limitations; they do not provide information on the type of activity and they are limited in the measurement of swimming/water-based activities, cycling, step/inclined activity, or strength exercises [74‐77]. By using both methods we will gain optimal insight in type, frequency, duration and intensity of PA that is needed to increase CF or slow down decline of CF.