An increasing number of studies have been devoted to reducing SB in patients with CVD, reflecting a favorable trend in SB and CVD. This scoping review summarized the characteristics, types, delivery modes, and outcome measures of the interventions to reduce SB in patients with CVD. Most eligible interventions were conducted within the last five years, possibly due to increased awareness among researchers of the correlation between SB and diseases and relevant guidelines in recent years. Overall, reducing SB time in patients with various types of CVD is feasible, with sound short-term effects postintervention.
First, regarding the evidence of intervention characteristics, few included interventions followed a theoretical framework [30, 36, 37]. Previous evidence has demonstrated the importance of a social and behavioral science-based theoretical foundation for public health and health promotion interventions [40]. Even so, behavior change interventions are often designed without theory application. Only three of the interventions we reviewed were developed based on theories [30, 36, 37]. Likewise, only 22.5% of the 235 studies in a recent meta-analysis explicitly employed behavior change theory [41]. There has been controversy regarding the benefits of theory application to interventions [42]. Our review suggests that whether a theoretical basis is provided has no significant impact on intervention efficacy. Prestwich et al. also reported that extensive application of theories might not improve the effectiveness of health behavior interventions [43]. Perhaps selecting the appropriate framework among many theories and designing intervention components step-by-step is challenging. Therefore, more methodologically rigorous studies are needed to determine the necessity of theoretical frameworks in SB intervention.
Then, we identified three intervention types, of which healthy lifestyle promotion and risk factor management were more comprehensive than the other two. It is intended to affect SB alongside other combined domains (e.g., smoking, nutrition). Nevertheless, all three types of intervention focused on reducing SB time through individual efforts, while other dimensions of the SB-related factors needed to be supplemented. For instance, Chastin et al. pointed out other modifiable factors that require a concerted effort by the public or others, such as public policy, interpersonal relationships, and the environment [44]. The interventions we reviewed were mainly conducted in home or community settings; it may be perceived as more accessible to extend healthcare support to extensive, remotely located cardiac patients [45]. However, for reasons such as disease episodes or treatment needs, CVD patients have been found to have a higher in-hospital SB level [46]. Therefore, supportive intervention programs can be constructed in the hospital setting to reduce SB and promote the recovery of physical function after discharge.
This review also found that some types of interventions targeting SB also included some elements of PA promotion. However, interventions targeting changes in SB rather than PA are the most successful interventions for SB reduction [47]. Unlike the definition of SB, physical inactivity is usually considered to not meet the physical activity guidelines [48, 49]. Individuals who meet recommended PA goals may be sedentary for prolonged periods during their remaining waking hours, while others who do not regularly engage in regular PA may be less sedentary because of their working environment or lifestyle. Therefore, SB’s intervention goals and strategies should differ from those for PA.
Reducing and breaking sedentary time is recognized as a goal in CVD prevention and management [50]. The results we reviewed showed significant improvements in SB after interventions. Interestingly, we found that these were mainly measured by changes in total sedentary time, with less focus on breaks in SB, such as the number of sit-to-stand transitions. However, sedentary patterns and total sedentary levels are equally important and should be addressed independently [51]. In other studies, SB intervention components had specific goals (e.g., 30 sit-to-stand transitions, SB interruption through exercise) and obtained significant results [52, 53]. Such sit-to-stand shift patterns can contract muscles, increase postural blood flow, and influence the biological processes of disease formation [53]. A cohort study found that participants with shorter sedentary durations, i.e., “shortened sitters” (< 15–30 minutes), had significant improvements in triglycerides, total cholesterol/HDL-C ratio, and LDL-C/HDL-C ratio compared to those with shorter average sedentary bout duration [54]. Similarly, Huang et al. significantly reduced BMI, body fat percentage, and HbA1c for every ten breaks in sitting time measured using accelerometers [55]. The above suggests a beneficial association between regular breaks in SB time and CVD risks. Especially in CVD patients, for safety and convenience reasons, brief sit-to-stand transitions may be easier to maintain in the long term. Therefore, future intervention goals should consider sedentary patterns in patients with CVD throughout the day as an equally important indicator as total sedentary time, with a detailed design and specification of the target behavior change pattern.
Another highlighted point is that the interventions delivered in this review extensively use the internet or mobile technologies. Technology-assisted interventions provide a helpful mode of information communication, activity tracking, and individualized interaction in this review but need to be improved in sustainability. A recent review indicated that the potential effects of using mobile technologies to decrease sedentary time were short-term and failed to clarify the sustained clinical effects [56]. Only three technology-based interventions we reviewed were measured at follow-up, but none observed significant, sustained effects [30, 35, 38]. The poor sustainability of the interventions may be related to the majority of the study population being elderly CVD patients. Ahmad et al. showed that older adults might confront barriers such as a lack of technical skills, perceived ability, and professional involvement regarding advanced technologies [57]. Therefore, the need for continuous postintervention guidance from implementers for technology-based interventions poses challenges to its long-term effectiveness. Future interventions should assess and support the technical skill level of participants and, if needed, provide additional training for those with limited mobile technology experience [58].
Moreover, multiple BCTs have been used to regulate SB as part of interventions to modulate behavior [59]. Among these, we recognize self-monitoring as a popular technique for SB interventions, similar to other research [60, 61]. Notably, this does not mean that the purposeful use of a single BCT can be more beneficial for behavior change. Schroé et al. reported that combinations of different BCTs are more practical for reducing SB [62]. Furthermore, although many techniques have already been used in the intervention we reviewed, some researchers did not mark them explicitly according to the BCT list. In contrast, each intervention designed by Balducci et al. was clearly labeled with the BCT on which it was based [20]. Based on the above discussion, we strongly recommend the use of BCTs as a rich source when designing multicomponent interventions, even testing possible effective combinations of BCTs to improve SB.
Finally, the differences in SB measurement may limit comparisons of intervention effects between studies. The International Physical Activity Questionnaire (IPAQ) has a few items that specifically evaluate SB (sitting and driving only) [63], and as a self-administered questionnaire, it may also induce recall bias. In addition, the validity of IPAQ measurements varies by target group characteristics and regions [64, 65]. In contrast, as objective and feasible alternatives, smart trackers or monitoring devices can record accurate data, including sedentary time, intensity, and patterns. However, contextual information regarding how the behavior occurred needs to be included. The respective limitations of both measurements should be rationally recognized. It is suggested to use intelligent trackers to monitor SB for the whole day and combine them with the subjective report to obtain comparable results [66].
Limitations
Although we used a rigorous methodology in conducting this review, some limitations remain. Studies that explicitly address SB interventions are limited, as “sedentary behavior” is an evolving concept with many synonyms, and potential omissions of related keywords might exist in retrieval. Many interventions were designed incorporating the concept of "physical activity," but the unclear distinction between SB and PA would have caused mixed recognition and analyses in the selected interventions. Further limitations include the heterogeneity of the selected study designs, so the intervention results for SB were not reported in a standardized approach. Future review researchers need to strictly differentiate the terminology concepts if there are more studies available and attempt to choose a standardized way to report the results of SB issues to improve the quality of the evaluation.
