An Overview of Exercise Training in Cardiac Rehabilitation Programs in Sub-Saharan Africa : A Systematic Review

Introduction: This study aimed to provide an overview of the research involving exercise training programs in cardiac rehabilitation programs in Sub-Saharan Africa (SSA). Methods: Relevant articles were searched in PubMed, LILACS, Web of Science, and Google Scholar using the keywords and medical subject headings Cardiac Rehabilitation AND Africa South of the Sahara AND (Exercise OR “Exercise therapy” OR “Exercise Movement Techniques”), without limitation concerning the publication date. To be included in the full analysis, the study had to be a controlled clinical trial designed and conducted in SSA, in which patients with cardiovascular diseases (CVD) carried out an exercise training program. Results: The searches resulted in 53 articles, of which 4 met all the inclusion criteria. The trials involved 374 participants with different cardiovascular diseases. The protocols used consisted of aerobic and combined (aerobic and resistance) training programs. Training sessions lasted up to 60 minutes and were held 3 times per week for 8-12 weeks at different training intensities throughout the studies. Conclusions: The current study shows that aerobic and combined training are effective in promoting beneficial effects on various cardio-respiratory variables in CVD patients. However, the effects of training programs on patients with CVD remains insufficiently investigated in SSA. Moreover, there is a lack of studies aiming to design exercise training programs that take into account the socio-economic challenges of the SSA region in the management of the main CVD.


Introduction
Historically, communicable, maternal and perinatal diseases as well as nutritional deficiencies represented predominant public health problems in Sub-Saharan Africa (SSA). 1,2 owever, current data indicates that the region is facing an increasing burden of noncommunicable diseases, such as stroke and heart disease, which constitute the principal components of cardiovascular diseases (CVD). 3,4 his increasing burden of CVD constitutes a consequence of the epidemiologic transition triggered mostly by the regional economic transition. 5Although CVD represents major public health problems in industrialized countries, the SSA region is only in the early stages of such epidemiologic transition.However, current data as well as projections regarding CVD and other major chronic diseases are worrying, as they predict a rise from 28% morbidity and 35% mortality in 1990 to 60% and 65%, respectively, by 2020. 6Young adults residing in urban areas and, increasingly, those in the low socioeconomic strata are mostly affected by CVD, which results in a significant economic challenge at individual, household, family, and government levels. 7Therefore, there is justification for preventive and therapeutic strategies to mitigate observed adverse trends in CVD.Several initiatives such as reduction in dietary salt intake, 8 increased fruit intake, 9 use of mass media, 10,11 and health promoting activities in schools have been shown to be effective approaches for implementing the principles and practice of health promotion.Although the beneficial effects of exercise have been widely demonstrated with various exercise programs, 12 this therapeutic strategy seems to be under-promoted in the rehabilitation of CVD in SSA.This study aimed to determine briefly the state of research involving physical exercise in cardiac rehabilitation in the SSA region through a mini-review of literature.

Search Strategy and Identification of Trials
A literature review allows researchers to access findings on four electronic databases: PubMed, LILACS, Web of Science, and Google Scholar, without limitation concerning the publication date.The following keywords and medical subject headings were used in the search: Cardiac Rehabilitation AND Africa South of the Sahara AND (Exercise OR "Exercise therapy" OR "Exercise Movement Techniques"); the results were limited to articles in the languages of English, Portuguese, or French.One author performed the article search and forwarded the results from each electronic database to the StArt tool (version 2.3.4.2), 13 a systematic review tool support that allows the centralization of databank results, automatic identification of redundant trials, and easiest management of trial selection and extraction processes.Afterwards, two authors independently evaluated the title and abstract of each trial in the databank through the StArt tool and excluded irrelevant trials in accordance with the inclusion criteria.Then, a full-text review was performed.After each selection step (title, abstract, and full-text evaluation successively), both authors checked the agreement of their databanks of accepted trials.In the event of a disagreement, a discussion that involved the third reviewer was conducted.

Study Selection
The studies included met the following criteria.

Study Design
Only controlled clinical trials designed and performed in Sub-Saharan Africa were included.

Participants
Only studies of cardiopathic patients were selected.

Intervention
Patients participated in exercise-training programs with single or multiple components.The intensity, duration, frequency, type, and length of exercise in each article were recorded.

Outcome Measures
Main outcome measures were recorded without any restriction.

Data Extraction
The following data was extracted from the included studies: participants' data (sample size, mean age, studied groups, and clinical status), exercise-training program parameters (intensity, duration, frequency, type, and length of exercise).The result sections were studied and all relevant results related to the training intervention effects on main or clinical outcomes were extracted and interpreted.

Results
The searches of electronic databases resulted in 53 clinical trials, of which 49 were excluded by the title and abstract screening; 4 selected articles remained.

Interventions
The trials included basically two different exercise programs: aerobic 14,15 and combined training. 16,17 aining sessions were held 3 times per week for 8 to 12 weeks at different training intensities.

Effects of Exercise
The effects of training on the main variables are described in Table 1.

Discussion
To the best of the authors' knowledge, this is the first study to investigate the state of research involving exercise training programs in cardiac rehabilitation in SSA.As a preliminary observation, the low number of included articles can be seen as reflecting the scarcity of studies involving exercise training programs designed to manage cardiovascular diseases in sub-Saharan Africa.In most cases, the literature related to cardiac rehabilitation in sub-Saharan Africa consisted of descriptive or epidemiological studies which highlight the emergency represented by the current burden of CVD. 18Moreover, most of the intervention studies International Journal of Medical Reviews.2017;4(3):86-90 focused on assessing the effectiveness of comprehensive strategies for the primary prevention and control of cardiovascular risk factors. 8,9 t should be emphasized that the SSA region is already in the early stages of its epidemiologic transition; 19 thus, it is still a priority to achieve a significant impact on projections regarding CVD and other major chronic diseases by promoting public policies firstly oriented on strategies for the prevention and control of the main cardiovascular risk factors.Within this general context, exercise training programs in the cardiac rehabilitation of CVD patients, as a secondary prevention strategy, get little attention.Briefly, the trials concluded that aerobic and combined (aerobic and resistance) training have been effective in promoting beneficial effects on various cardiorespiratory variables in patients with hypertension (67% of participants), hypertensive heart disease, and chronic heart failure.Evidence showed that these diseases are currently among the main CVD in the SSA region, 20 and according to the available projections, it is expected that their impact will be greater in the coming years. 21evertheless, other evidence indicated an increasing risk for other CVD, such as diabetes 22 and stroke 23 in the SSA region.Therefore, studying, in the SSA region, the contribution of exercise training to improving physiological functions of patients with such diseases could be of great relevance.The trials involved only aerobic 14,15 and combined 16,17 training programs.In addition to pharmacological 24 and non-pharmacological therapeutic strategies, 25 exercise training is an essential intervention for improving physical function in CVD patients.Guidelines are based on vast evidence that demonstrates the effects of exercise protocols on improving specific physiological functions threatened by the CVD process. 26,27 or instance, it has been firmly established that aerobic and resistance training improves arterial stiffness, 28 lipid profiles and inflammatory status 29 , and modifies cardiovascular disease risk factors. 30hus, it can be seen that the results of the trials in the current study are consistent with those of previously reported studies.However, these studies involved exercise training programs which constitute a small part of the known and recommended exercise modalities in CVD management.Moreover, there are no studies aiming to design an exercise training program adapted to local socio-economic challenges.Therefore, investigating the effects of other exercise programs designed according to local socio-economic conditions in order to develop therapeutic methods as secondary prevention strategies in the management of CVD in SSA seems to be a relevant issue.The current review has some limitations.First, the heterogeneity of the included clinical trials (regarding the populations' clinical status, cardiovascular variables, and parameters of the exercise training programs) hindered the performance of a metaanalysis which could accurately determine the magnitude of the improvement in each cardiovascular variable triggered by each exercise training program.Secondly, these findings cannot be extrapolated to other CVD in the SSA region.Furthermore, the studied trials were designed to investigate the effects of aerobic and combined training only.

Conclusions
The findings of this brief review show that the effectiveness of exercise training in cardiac rehabilitation remains under-investigated.Moreover, there is a lack of research aiming to design exercise training programs that take into account the socio-economic challenges of the SSA region in the management of the main CVD.Further studies with higher methodological quality are needed to investigate the effects of different exercise training modalities and their combinations in patients with diverse CVD.

Table 1 .
Characteristics of Selected Studies