Lifelong changes in physical activity behaviour through phase II cardiac rehabilitation? Still steps to take!

Comprehensive cardiac rehabilitation (CR) aims to induce a lifelong healthy active lifestyle in patients with cardiovascular (CV) diseases.1 But, do we succeed in this objective? We have scant data about the effectiveness of CR programmes on physical activity (PA) in the long-term.2 In this study, we aim to add scientific evidence on the sustainability of participating in a CR programme by evaluating PA and cardiorespiratory fitness (CRF) 2 years after completion of phase II CR in a subsample of coronary artery disease patients who participated in the TeleRehabilitation in Coronary Heart disease (TRiCH) study.3 In brief, TRiCH3 was a randomised controlled trial comparing the effects of 3 months of home-based exercise with remote guidance, supervised centre-based exercise or usual care in 90 coronary artery disease patients (61.2 ± 7.6 years, 89% men) graduating from conventional phase II CR. Outcome measures included PA, CRF, CV risk factors and quality of life. A total of 54 (60%) participants (64.8 ± 7.0 years; 82% men; 18 home-based group, 21 centre-based group, 15 usual care) returned for 2-year follow-up measurements of PA and CRF. A Sensewear Mini Armband (BodyMedia Inc., Pittsburgh, USA) was used to objectively measure PA. Outcome measures included number of daily steps and number of minutes spent at moderate and vigorous PA (MVPA) (≥3 metabolic equivalents of task (METs), min/day). A graded cardiopulmonary exercise test was used to evaluate CRF (peak oxygen consumption (VO2)). Mixed-design analyses of variance were applied to assess differences over time, between groups and their interaction. Pearson and Spearman correlations were performed to assess the correlation between (changes in) PA and (changes in) CRF. Analysis of variance or Kruskal–Wallis H-tests were used to assess differences in change of PA across tertiles of participants based on their change in peak VO2. All analyses were done using R software version 3.5.1 (R-foundation, Vienna, Austria). A two-tailed p-value < 0.05 was considered statistically significant. At baseline, all three groups were comparable with regard to age and gender (p > 0.05 for all). Furthermore, we found no differences between returners and non-returners with regard to age, sex, CRF and MVPA at completion of their phase II programme (data not shown). Table 1 shows an overall decrease in daily steps (p-time = 0.007) and minutes of MVPA (p-time = 0.034) from baseline to follow-up. Changes were similar among all groups (p-interaction > 0.05 for all). Overall, step count was approximately 1000 steps/day lower after 2 years, which has previously been shown to be clinically relevant.4 Whereas, guidelines recommend at least 30 min of MVPA per day or 150 min per week,1 van Remoortel et al.5 suggested a minimum of 80 min/day when using a Sensewear Mini Armband to achieve the guidelines. Taking this into account, 83.3% (n = 45) of participants achieved the recommended daily amount of PA at baseline and 70.4% (n = 38) of participants at 2 years of follow-up. Furthermore, we found significant declines in all submaximal indexes of CRF at the first ventilatory threshold (VT1)6 (p < 0.001 for all) but to our surprise, peak VO2 (Figure 1 and Table 1) remained stable. More detailed inspection revealed that 33% of the participants (n = 18) showed a clinically relevant decline in peak VO2 of ≥3.5 ml.kg−1.min−1. As previous observational data showed that an equivalent increase in exercise capacity exerts beneficial effects on mortality, the documented decline could have clinical consequences.8 Correlation analyses documented a moderate relationship between changes in MVPA (r = 0.32, p = 0.022), steps (r = 0.44, p < 0.001) and changes in peak VO2 (ml.kg−1.min−1). When we divided patients into tertiles based on change in peak VO2, significant differences between change in MVPA (p = 0.04) and steps (p = 0.001) were found, with patients who increased their fitness also showing increases in daily MVPA and steps. Differences within and between groups at completion of phase II cardiac rehabilitation (CR) and two-year follow-up. EE: energy expenditure; FU: follow-up; MVPA: moderate to vigorous physical activity; RER: respiratory exchange rate; SBP: systolic blood pressure; VO2: oxygen consumption; VT1: first ventilatory threshold. Wasserman % refers to physical fitness compared with the normal values developed by Wasserman et al.7 Differences within and between groups at completion of phase II cardiac rehabilitation (CR) and two-year follow-up. EE: energy expenditure; FU: follow-up; MVPA: moderate to vigorous physical activity; RER: respiratory exchange rate; SBP: systolic blood pressure; VO2: oxygen consumption; VT1: first ventilatory threshold. Wasserman % refers to physical fitness compared with the normal values developed by Wasserman et al.7 Comparison of peak oxygen consumption over time for all grroups combined. Whereas there is a wealth of high-quality evidence supporting the short-term benefits of participation in CR on health-related CRF measures and PA,9 there is a lack of data documenting sustainable lifestyle modifications following enrolment in a CR programme in the long-term (>12 months).2 Interestingly, CRF was maintained 2 years after completion of CR, with no difference between usual care or a three-month prolonged CR programme (centre-based or home-based). These results are in line with earlier intervention studies showing good preservation of CRF in patients who were readmitted to CR on average 16 months after previous discharge.10 However, it should be acknowledged that the overall study participant is probably fitter and more motivated compared with the average patient completing CR,10 as there is a known selection bias in exercise training studies. Yet at completion of their ambulatory CR programme, both returners and non-returners were similar with regard to CRF and MVPA. Furthermore, our results suggest that just prolonging the exercise component of CR for a short period, either in a supervised setting or by 3 months of remotely guided home-based exercise, is not superior compared with usual care to maintain PA levels in the long-term. After 2 years, a similar decline in PA, assessed as steps and minutes of MVPA, was observed in all groups. This decline is clinically important as Lahtinen et al.11 reported earlier that patients moving from active to inactive at 2 years of follow-up had a 2.4-fold risk of cardiac death. As such, our results emphasise the necessity of continuous telemonitoring or assessing of PA and provision of the necessary professional guidance and feedback to the patients to support a lifelong compliance with an active lifestyle. Indeed, Lunde et al.12 documented that using a smartphone application could already increase PA behaviour and CRF after completion of phase II CR over a period of 1 year. This was in line with a recent meta-analysis documenting small but significant effect sizes for PA following e-health CR13 ( = CR delivered or supported by information and communication technology) and guidelines for the implementation of e-cardiology interventions have been published.14 Yet, the follow-up period in the majority of e-health studies to date has been less than 1 year, so we need well-powered randomised controlled trials to provide evidence on the effectiveness of using these newer technologies to reach our goal of sustained lifestyle modifications. The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article. The author(s) received no financial support for the research, authorship and/or publication of this article.