Assessing the ‘active couch potato’ phenomenon in cardiac rehabilitation: rationale and study protocol

Freene et al. BMC Health Services Research (2016) 16:75 DOI 10.1186/s12913-016-1313-x STUDY PROTOCOL Open Access Assessing the ‘active couch potato’ phenomenon in cardiac rehabilitation: rationale and study protocol Nicole Freene1* , Borja del Pozo Cruz2 and Rachel Davey3 Abstract Background: There is little evidence of whether or not those who have attended cardiac rehabilitation (CR) are meeting the physical activity guidelines recommended for secondary prevention of cardiovascular disease. In healthy individuals, there is evidence, that even if individuals are meeting the physical activity guidelines, the harmfulness of too much sedentary behaviour remains (active couch potato (ACP) phenomenon). Currently, there appears to be no evidence of the ACP phenomenon in those attending CR. The aims of the study are to examine the level of physical activity and sedentary behaviour in those with coronary heart disease (CHD) who have attended CR, and to investigate the potential independent associations between these behaviours and cardio-metabolic health, health-related quality of life, exercise capacity, anxiety and depression. Methods: A prospective cohort study will be conducted in Australia over 12-months. Baseline data from this study will contribute to an international, multi-centre cross-sectional study (Australia, New Zealand, United States of America, South Africa, Spain, and Portugal). Adults currently enrolled in a 6-week phase II cardiac rehabilitation program with stable CHD and receiving optimal medical treatment +/− revascularisation will be recruited. Outcome measures will be taken at baseline (commence CR), 6 weeks (complete CR), 6 and 12-months. Physical activity and sedentary behaviour will be measured using accelerometry and two questionnaires (Active Australia Survey, Past-Day Adults’ Sedentary Time questionnaire). Health outcomes will include body mass index, waist-to-hip ratio, lipid profile, blood glucose level, quality-of-life (MacNew), exercise capacity (6-min walk test), anxiety and depression (Hospital Anxiety and Depression Scale). Discussion: There has been limited investigation of the physical activity levels and sedentary behaviour of individuals with CHD attending CR. There are no studies assessing the relationship of these behaviours with health outcomes over the short and medium-term. As in healthy individuals, physical activity and sedentary behaviour may have independent effects on cardiovascular risk factors in people with CHD, which may contribute to recurrent cardiovascular events. If this is so, reducing sedentary behaviour may be a feasible first-line, additional and more achievable strategy to improve the health of those with CHD, alongside traditional recommendations to increase the time spent in moderate-to-vigorous intensity physical activity. Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12615000995572 Keywords: Coronary heart disease, Sedentary behaviour, Physical activity * Correspondence: 1 Physiotherapy, Faculty of Health, University of Canberra, Canberra ACT 2601, Australia Full list of author information is available at the end of the article © 2016 Freene et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Freene et al. BMC Health Services Research (2016) 16:75 Background Heart disease is the leading single cause of death of men and women in Australia, and is prevalent worldwide [1, 2]. It is estimated that 34 % of all heart attacks in Australia are repeat events [3]. Not only are repeat cardiac events more likely to be fatal, they result in a higher burden of disease cost than initial events, with the total economic cost of repeat cardiac events in Australia amounting to $8.4 billion in 2010 [3]. Internationally, it is recommended that all those with coronary heart disease (CHD) be offered cardiac rehabilitation (CR), a secondary prevention program. It is widely recognised that CR decreases mortality, improves risk profiles, decreases hospital admissions, increases medication adherence and improves quality of life [4–7]. CR programs are usually exercise-based, consisting of either regular exercise alone, or a combination of exercise with education and psychological support. Moderate-intensity aerobic exercise, or physical activity, is considered a core component of CR [5, 8]. CR participants are encouraged to increase their moderate-intensity aerobic physical activity slowly and gradually, aiming to accumulate a minimum of 30 min on most, or all, days of the week, throughout life [8]. However, little is known about how much physical activity these individuals undertake outside of the CR program. It is not clear whether CR participants’ are meeting the physical activity guidelines as recommended for secondary prevention, with some indication that only 8.4 min per day of moderate-to-vigorous intensity physical activity (MVPA) is achieved in the first 12 months following diagnosis of CHD [9–11]. In healthy individuals, there is evidence that even if you do enough physical activity to meet the recommendations, by sitting too much (sedentary behaviour), the harmfulness of too much sitting time remains (the ‘active couch potato’ (ACP) phenomenon) [12]. The few prospective studies that have attempted to research this phenomenon have reached the same conclusion: meeting the public health guidelines regarding physical activity (150 min moderate-to-vigorous intensity aerobic physical activity per week) may not necessarily protect against the possible harmful effects from excessive sedentary behaviour [12, 13]. It appears that the more sedentary you are, the more likely you are to die from any cause, with sedentary behaviour recently being considered an independent risk factor for cardiovascular disease and all-cause mortality [14–16]. There is also some evidence that those with cardiovascular disease or diabetes are more likely to die from any cause if they sit for too long, independent of physical activity [17]. Therefore, it is important to take into consideration sedentary behaviour when working towards secondary prevention in those with CHD, intending to prevent further cardiac events. Page 2 of 6 To our knowledge there are limited studies assessing the effect of physical activity on health outcomes in people with CHD, with no identified studies assessing the effect of sedentary behaviour [18]. The general aim of the current study is two-fold: a) t (...truncated)