Rev Bras Fisiol Exerc 2020;19(1):40-53

doi: 10.33233/rbfe.v19i1.3984

REVIEW

Comparison of continuous moderate training with high intensity interval training on variables of the cardiopulmonary exercise test in patients with coronary artery disease: a meta-analysis

 

Francisco Tiago Oliveira de Oliveira1, Paula Guerra Duplat2, Cristiane Maria Carvalho Costa Dias3

 

1Master in medicine and human health by Universidade Federal da Bahia, 2Physiotherapist graduated by Escola Bahiana de Medicina e Saúde Pública, 3PhD in medicine and human health by Escola Bahiana de Medicina e Saúde Pública

 

Received on October 23, 2019; accepted on February 14, 2020.

Corresponding author: Francisco Tiago Oliveira de Oliveira: franciscooliveira@bahiana.edu.br

 

Francisco Tiago Oliveira de Oliveira: franciscooliveira@bahiana.edu.br

Paula Guerra Duplat: fisio.pauladuplat@gmail.com

Cristiane Maria Carvalho Costa Dias: cmccdias@bahiana.edu.br

 

Abstract

Background: The objective of Cardiovascular rehabilitation is reducing the risks of mortality with two training modalities: high intensity interval training (HIIT) and moderate continuous intensity training (MIT). The exercise prescription is performed by cardiopulmonary exercise test. There are differences about which one is the best training for this patient. Aim: To compare the effects of HIIT and moderate continuous training on the variables of the cardiopulmonary exercise test (CPX) in patients with coronary artery disease. Methods: This is a systematic review of randomized clinical trials on coronary artery disease. This study was registered on PROSPERO. The search was executed on the databases: Medline, Scielo, Lilacs and Pedro. The selection of studies was a two-phase process: Reading of title and abstract and reading of full article. The data extraction was performed by the transcription of information. The methodological quality was evaluated by the PEDro scale and the risk of bias scale. The statistical analysis was performed using the RStudio software by random effect model and was applied the Q-Cochran test to evaluate the statistical heterogeneity. Results: 10 clinical trials were included. The methodological quality assessed by PEDro generated scores of four to nine, and the bias risk scale detected a low risk of bias. For the variables:  VO2peak (p = 0.04), Ventilatory Threshold (p = 0.05), HR max (p = 0.01), SBP max (p = 0.02), the HIIT proved to be more effective. The other variables did not present differences between the two modalities. Conclusion: HIIT showed to be the most effective training modality for the increase of VO2max, Ventilatory Threshold, SBP max and HR max.

Keywords: coronary heart disease; high intensity interval training; moderate continuous training.

 

Resumo

Comparação do exercício de moderada intensidade contínuo com exercício intervalado de alta intensidade nas variáveis do teste cardiopulmonar em pacientes com doença arterial coronariana: uma metanálise

Introdução: A reabilitação cardiovascular tem o objetivo de reduzir os riscos de mortalidade e dentro dessa intervenção há duas modalidades de treino: treinamento intervalado de alta intensidade (HIIT) e o exercício moderado contínuo (MIT). A prescrição de exercício é realizada pelo teste cardiopulmonar. Há divergência sobre qual a melhor modalidade de exercício para este paciente. Objetivo: Comparar os efeitos do HIIT com os do exercício contínuo nos parâmetros do teste cardiopulmonar em pacientes com doença arterial coronariana. Métodos: Trata-se de uma revisão sistemática de ensaios clínicos randomizados em coronariopatas. Registrou-se o estudo na PROSPERO. Foram realizadas as buscas nas bases de dados Medline, Scielo, Lilacs e Pedro. A seleção de estudos foi realizada em duas etapas: leitura de título e resumo e leitura do artigo na íntegra. A extração dos dados foi realizada pela transcrição das informações. A qualidade metodológica foi avaliada pela escala PEDro e escala risco de viés. A análise estatística foi feita com o programa RStudio pelo modelo randômico e o teste Q-Cochran para avaliar a heterogeneidade estatística. Resultados: Foram incluídos 10 ensaios clínicos. A qualidade metodológica avaliada pela Pedro gerou notas de quatro a nove, e a escala risco de viés detectou baixo risco de viés. Para as variáveis: VO2pico (p = 0,04), limiar ventilatório (p = 0,05), FC máx (p = 0,01), PAS máx (p = 0,02), o HIIT mostrou ser mais eficaz. As demais variáveis não apresentaram diferença entre as duas modalidades. Conclusão: O HIIT mostrou ser a modalidade treinamento mais eficaz para o incremento do VO2máx, limiar ventilatório, PAS máx e FC máx.

Palavras-chave: doença arterial coronariana; treinamento intervalado de alta intensidade; exercício.

 

Introduction

 

The Coronary Artery Disease (CAD) is one of the leading causes of death in the world [1,2]. Currently in the Brazilian scenario, there has been an increase in the number of deaths from cardiovascular diseases (CVD) in recent years; in 2017 alone, an estimated 383,961 deaths were caused by the disease [3]. The increase in the number of deaths in the last five years directly affected the country’s economy with the increase in the number of surgical hospitalization, consultations with the cardiologists, costs with medicine and social security. In this context were created strategies for reduction of those costs [4].

The cardiovascular rehabilitation has the aim to increase the functional capacity and quality of life beyond reducing the risk of morbidity and mortality and hospitalization [5-7]. The cardiopulmonary exercise test (CPX test) is the gold standard method for functional evaluation and to determine the CD severity. In addition, data extracted from the test are useful to guide the clinical prescription of exercise in cardiovascular rehabilitation. Among the most relevant are Heart Rate Maximum (HR max), Maximum oxygen consumption (VO2max) and Ventilatory Threshold (VT) [8-12].

Among the types of aerobic training in the cardiac rehabilitation program the high intensity interval training (HIIT) and moderate continuous intensity training (MIT) are used. The interval training is executed with periods of high intensity (70% of VO2max) interleaved by periods of moderate or low intensity (25% a 40% do VO2max) [13]. The continuous training consists in a constant effort and is executed with moderate intensity in stable state [14-16].

The professionals have divergent opinions on which is the best modality of exercise for the treatment of CAD, and there is a gap about the effect of HIIT and MIT in the other variables evaluated on the cardiopulmonary exercise test. Based on this fact, it is necessary to synthesize the existing results in the literature to allow its extrapolation to other populations and encourage new clinical research. Thus, the aim of this study is to compare the effects of HIIT and moderate continuous training on the variables of the CPX test in patients with coronary artery disease.

 

Methods

 

This is a systematic review with meta-analysis and Guideline PRISMA guidelines will be followed [17]. This study was registered in the database PROSPERO with the code: CRD42017069574.

 

Eligibility criteria

 

This review included randomized clinical trials carried out in patients with coronary artery disease, whom performed the cardiopulmonary exercise test and compared the effects between HIIT and moderate continuous exercise performed in clinical environment (Phase II). It excluded study protocol and research about rehabilitation in patients with CAD associated to other diseases like stroke and peripheral arterial obstructive disease.

 

Search strategy

 

The search was initially performed by two blind researchers, with the same strategy and then the articles selected were evaluated together. When there was disagreement between the two researchers, a third researcher was called for definition. We searched the databases Medline (Accessed via Pubmed), Scielo, Pedro and Lilacs, through the strategy PICOS. MeSH Thesaurus and DeCS were used to find the descriptors and their synonyms.

There are the descriptors included on the search strategy: ((((((((((((((((((((((((artery disease, coronary) OR artery diseases, coronary) OR coronary artery diseases) OR disease, coronary artery) OR diseases, coronary artery) OR coronary arteriosclerosis) OR arteriosclerosis, coronary) OR coronary arteriosclerosis) OR atherosclerosis, coronary) OR atherosclerosis, coronary) OR coronary atherosclerosis) OR coronary atherosclerosis) OR arteriosclerosis, coronary) OR coronary diseases) OR coronary heart disease) OR disease, coronary) OR diseases, coronary) OR coronary heart diseases) OR diseases, coronary heart) OR heart disease, coronary) OR heart diseases, coronary)) AND ((((((((((((((high intensity interval training) OR high-intensity interval trainings) OR interval training, high-intensity) OR interval trainings, high-intensity) OR training, high-intensity interval) OR trainings, high-intensity interval) OR high-intensity intermittent exercise) OR exercise, high-intensity intermittent) OR exercises, high-intensity intermittent) OR high-intensity intermittent exercises) OR sprint interval training) OR sprint interval trainings) OR hiit) OR intermittent training) OR aerobic interval training)) AND (((((((moderate continuous intensive exercise) OR continuous training at moderate intensity) OR aerobic continuous training) OR moderate continuous training) OR continuous training) OR moderate-intensity continuous training) OR continuous moderate exercise). The search was filtered with the filter: Clinical trial without restriction of year and language.

 

Data collect

 

The selection of the studies was performed in two moments. In the first moment: reading the title and summary of the article and in the second moment: reading the complete article. The data was extracted through transcription of the information and a file was created, containing the identification of the article (author and year), methodology and results. To obtain additional information, we consulted a researcher experienced in the area and searched the references of the articles collected.

The methodological quality of the studies was independently assessed using the PEDro scale and the bias risk scale [18,19]. The items evaluated were: randomization technique; blinding technique; intention-to-treat analysis; and reporting losses or exclusions.

 

Statistical analyses

 

The dependents variables are: Maximum Oxygen Consumption (VO2max), Ventilatory Threshold (VT), Oxygen Pulse, Inclination of the ventilatory equivalent of carbon dioxide (VE/VCO2 slope), respiratory exchange ratio (VO2/VCO2), Workload, Maximum Blood Pressure and Maximum Heart Rate; and the independent variables are exercise intensity, training modality, number of participants, age, sex BMI, ejection fraction.

The program RStudio version 1.0.143 for Windows was used for elaboration, data analysis and construction of the Forest Plot chart. Statistical heterogeneity was assessed by visual inspection of the confidence interval and by the Q-Cochran test and chi-square test (c2). Data was analyzed using the random effect model.

 

Results

 

Ten studies were included in this meta-analysis. Among the samples collected, there were a total of 678 patients with a diagnosis of stable CAD, according to the eligibility criteria of the clinical trials. Participants exercised at least three times a week for 45 minutes for a period of 12 weeks. The researchers used different methods for the prescription of physical exercise, the variables used were: the percentage of VO2max, VO2 relative to the anaerobic threshold, percentage of HR max and peak power of work.

 

 

 

Flow diagram 1 - Search strategy results

 

 

Table I - Description of characteristics of the clinical trial population in patients with CAD (See PDF)

 

Table II - Description of clinical trial protocols included in systematic review and their respective results (see PDF)

 

 

The methodological quality of the studies was evaluated by the PEDro scale and by the risk of bias scale. In the PEDro scale, the lowest score was: 4 and the highest score was: 9. The risk of bias was assessed by the bias risk scale. The results of the scale detected low risk of bias among the studies included in the review.

 

Table III - Evaluation of the methodological quality of the studies included in the meta-analysis

 

 

The cut-off point adopted by the authors to consider the study of high methodological quality was ≥ 7.

 

 

Figure 1 - Evaluation of the risk of bias through the risk of bias scale of the studies included in the meta-analysis

 

Submitted below are the results of the quantitative synthesis through the graphical analysis.

 

 

Figure 2 - Graphical analysis of the variable: VO2 peak

 

 

Figure 3 - Graphical analysis of the variable: VO2 peak, only with the articles of high methodological quality

 

 

Figure 4 - Graphical analysis of the variable: Ventilatory threshold

 

 

Figure 5 - Graphical analysis of the variable: ventilatory threshold, only with the articles of high methodological quality

 

 

Figure 6 - Graphical analysis of the variable: maximum heart rate (HR max)

 

 

Figure 7 - Graphic analysis of the variable: maximum heart rate, only with the articles of high methodological quality

 

Discussion

 

This meta-analysis is unique in comparing the effects of HIIT and continuous moderate intensity exercise (MIT) on the various variables evaluated in the cardiopulmonary test. In the design of the clinical trials after the interventions, a comparison was made between the parameters evaluated in ergospirometry before and after the exercise. This study found that in subjects with CAD, there was a superiority of HIIT over MIT for the following parameters: VO2 peak, Ventilatory Threshold (VT), and HR max.

The VO2 peak is considered the main variable in the cardiopulmonary test, because it has a strong correlation with survival, quality of life and the evaluation of the functional capacity. This same result was found in other studies conducted in patients with CAD, acute myocardial infarction (AMI) and heart failure (HF) [30,31]. With these results, the social and cultural paradigm that cardiopathy patients can only perform low-intensity aerobic exercises is undone.

The first ventilatory threshold, also called anaerobic threshold or aerobic threshold is a very important variable obtained in CP. This point is defined as the first ventilation tipping point for carbon dioxide (CO2) elimination due to lactate buffering by sodium bicarbonate. The earlier this point occurs during an incremental test, the lower an individual's ability to perform sustained aerobic activities [32-34], which corroborates the results of the present study.

The representative variables of cardiac function as HR max were increased for individuals who underwent HIIT [9,33,34]. However, a meta-analysis published in 2017 when comparing HIIT with MIT in cardiac patients did not find any difference between the exercise modalities for maximal heart rate and blood pressure. This result was justified by the short time of intervention and the comprehensive number of the cardiopathic population [34].

Of the studies included in the sample only three showed to be of high quality, and, when performing a secondary analysis only with these clinical trials, a change was contacted in the results contained in the general quantitative synthesis, because there was no difference between the modalities of exercise for variables: VO2 peak, VT, HR max. This phenomenon can be explained by the reduced sample size between the studies, which suffered a variation of 8 to 36 participants and by the protocol chosen to perform the test, which used two distinct instruments: the cycler and the treadmill and few studies were included in this secondary analysis. The largest deficits found in the other seven studies contemplated in this research were the non-description of randomization techniques, absence of the technique of blinding and loss of participants above 15%.

Thus, it is necessary to carry out better studies, and a deficit of research with the Brazilian population of heart patients is pointed in the literature. This review presents as probable limitation the time bias and information bias due to the methodological quality of the studies, and the strengths of this study are: systematic methodology, comprehensive search in the literature, presence of meta-analysis, evaluation of methodological quality of clinical trials and explicit and reproducible eligibility criteria.

 

Conclusion

 

High Intensity Interval Training proved to be the most effective training modality for increment of VO2max, ventilatory threshold and maximum heart rate in patients with coronary artery

 

Acknowledgements

 

I thank the Grupo de Pesquisa em Fisioterapia Cardiovascular e Respiratória da Bahiana (Gepfir) for welcoming and contributing to this work.

 

References

 

  1. Cesar LA, Ferreira JF, Armaganijan D, Gowdak LH, Mansur AP, Bodanese LC et al. Diretriz de Doença Coronária Estável. Arq Bras Cardiol 2014;103(2Supl2):1-59.
  2. Moran AE, Forouzanfar MH, Roth GA, Mensah GA, Ezzati M, Murray CJL. Temporal trends in ischemic heart disease mortality in 21 world regions, 1980 to 2010 The Global Burden of Disease 2010 Study Andrew. Circulation 2014;129(14):1483–92.
  3. SBC SBDC. Cardiomêtro. Mortes por doenças cardiovasculares no Brasil. Available from: http://www.cardiometro.com.br/anteriores.asp
  4. Sá A, Siqueira E, Siqueira-Filho AG, Gerardin M, Land P. Análise do impacto econômico das doenças cardiovasculares nos últimos cinco anos no Brasil. Arq Bras Cardiol 2017;39-46. https://doi.org/10.5935/abc.20170068
  5. Claudio A, Nóbrega L, Castro RRT, Negrão CE, Stein R, Serra SM. Diretriz de Reabilitação Cardíaca. Arq Bras Cardiol. 2005;84(5):431–40. https://doi.org/10.1590/S0066-782X2005000500015
  6. Rabelo D, Araújo CGS. Reabilitação cardíaca com ênfase no exercício? uma revisão sistemática. Rev Bras Med Esporte 2006;12:279-85.
  7. Muela H, Bassan R, Serra S. Avaliação dos benefícios funcionais de um programa de reabilitação cardíaca. Rev Bras Cardiol 2011;24(4):241–50.
  8. Serra S. Considerações sobre ergoespirometria. Arq Bras Cardiol 1997;68(4):301–4.
  9. Negrão CE, Barretto ACP. Cardiologia do Exercicio. 3o. São Paulo: Manole; 2010. 725 p.
  10. Dourado VZ. Exercicio físico aplicado a reabilitação pulmonar. 1a ed. Rio de Janeiro: Revinter; 2011. 348 p.
  11. Herdy AH, Ritt LEF, Stein R, Araújo CGS, Milani M, Meneghelo RS et al. Cardiopulmonary exercise test: fundamentals, applicability and interpretation. Arq Bras Cardiol 2016;467-81. https://doi.org/10.5935/abc.20160171
  12. Gomes ELFD, Silva DS, Costa D. Testes de avaliação da capacidade física em pediatria. Fisioter Bras 2012;13(6):469-75. https://doi.org/10.33233/fb.v13i6.586
  13. Gillen JB, Gibala MJ. Is high-intensity interval training: a time-efficient exercise strategy to improve health and fitness? Appl Physiol Nutr Metab 2014;39(3):409-12. https://doi.org/10.1139/apnm-2013-0187
  14. Herdy AH, López-Jiménez F, Terzic CP, Milani M, Stein R, Carvalho T et al. Diretriz sul-americana de prevenção e reabilitação cardiovascular. Soc Bras Cardiol 2014;103(1):1-30. https://doi.org/10.5935/abc.2014S003
  15. Alves VLS, Guizillini S, Umeda IIK, Pulz C, Medeiros WM. Fisioterapia em Cardiologia. 2a ed. São Paulo: Ateneu; 2014. 387 p.
  16. Zuhl M, Kravitz L. HIIT vs continuous endurance training: battle of the aerobic titans. Fit J 2012.
  17. Moher D, Liberati A, Tetzlaff J, Altman DG. Principais itens para relatar revisões sistemáticas e meta-análises: A recomendação PRISMA*. Epidemiol Serv Saúde 2015;24(2):335-42. https://doi.org/10.5123/S1679-49742015000200017
  18. Pedro E. Escala de PEDro – Português (Portugal) 1. 2009;1-7. https://www.pedro.org.au/wp-content/uploads/PEDro_scale_portuguese(portugal).pdf
  19. Carvalho APV, Silva VGA. Avaliação do risco de viés de ensaios clínicos randomizados pela ferramenta da colaboração Cochrane. Diagn Tratamento 2013;18(1):38-44.
  20. Rognmo Ø, Hetland E, Helgerud J, Hoff J, Slørdahl SA. High intensity aerobic interval exercise is superior to moderate intensity exercise for increasing aerobic capacity in patients with coronary artery disease. Eur J Cardiovasc Prev Rehabil 2004;11(3):216-22. https://doi.org/10.1097/01.hjr.0000131677.96762.0c
  21. Warburton DER, Mckenzie DC, Haykowsky MJ, Taylor A, Shoemaker P, Ignaszewski AP et al. Effectiveness of high-intensity interval training for artery disease. Am J Cardiol 2005;95(9):1080-4. https://doi.org/10.1016/j.amjcard.2004.12.063
  22. Currie KD, Dubberley JB, McKelvie RS, MacDonald MJ. Low-volume, high-intensity interval training in patients with CAD. Med Sci Sports Exerc 2013;45(8):1436-42. https://doi.org/10.1249/MSS.0b013e31828bbbd4
  23. Currie KD, Bailey KJ, Jung ME, Mckelvie RS, Macdonald MJ. Effects of resistance training combined with moderate-intensity endurance or low-volume high-intensity interval exercise on cardiovascular risk factors in patients with coronary artery disease. J Sci Med Sport 2015;18(6):637-42. https://doi.org/10.1016/j.jsams.2014.09.013
  24. Keteyian SJ, Hibner BA, Bronsteen K, Kerrigan D, Aldred HA, Reasons LM et al. Greater improvement in cardiorespiratory fitness using higher-intensity interval training in the standard cardiac rehabilitation setting. J Cardiopulm Rehabil Prev 2014;34(2):98-105. https://doi.org/10.1097/HCR.0000000000000049
  25. Cardozo GG, Oliveira RB, Farinatti PTV. Effects of high intensity interval versus moderate continuous training on markers of ventilatory and cardiac efficiency in coronary heart disease patients. Scientific World Journal 2015;2015:192479. https://doi.org/10.1155/2015/192479
  26. Conraads VM, Pattyn N, De Maeyer C, Beckers PJ, Coeckelberghs E, Cornelissen VA et al. Aerobic interval training and continuous training equally improve aerobic exercise capacity in patients with coronary artery disease: The SAINTEX-CAD study. Int J Cardiol. 2015;179:203-10. https://doi.org/10.1016/j.ijcard.2014.10.155
  27. Jaureguizar KV, Vicente-Campos D, Bautista LR, Peña CH, Gómez MJA, Rueda MJC et al. Effect of high-intensity interval versus continuous exercise training on functional capacity and quality of life in patients with coronary artery disease: a randomized clinical trial. J Cardiopulm Rehabil Prev 2016;36(2):96-105. https://doi.org/10.1097/HCR.0000000000000156
  28. Prado DML, Rocco EA, Silva AG, Rocco DF, Pacheco MT, Silva PF et al. Effects of continuous vs interval exercise training on oxygen uptake ef fi ciency slope in patients with coronary artery disease. Braz J Med Biol Res 2016;49:1-7. https://doi.org/10.1590/1414-431X20154890
  29. Pattyn N, Beckers PJ, Cornelissen VA, Coeckelberghs E, Maeyer C, Frederix G et al. The effect of aerobic interval training and continuous training on exercise capacity and its determinants. Acta Cardiol 2017;72(3):328-40. https://doi.org/10.1080/00015385.2017.1304712
  30. Hannan AL, Hing W, Climstein M, Coombes JS, Byrnes J, Furness J. High-intensity interval training versus moderate- intensity continuous training within cardiac rehabilitation? a systematic review and. Open Access J Sports Med 2018;9:1-17. https://doi.org/10.2147/OAJSM.S150596
  31. Hussain SR, Macaluso A, Pearson SJ. High-Intensity interval training versus moderate-intensity continuous training in the prevention / Management of Cardiovascular Disease. Cardiol Rev 2016;24(6):273-81. https://doi.org/10.1097/CRD.0000000000000124
  32. Brum PC, Negrão CE. Adaptações agudas e crônicas do exercício físico no sistema cardiovascular. Rev Paul Educ Fís 2004;18:21-31.
  33. Umpierre D, Stein R. Efeitos hemodinâmicos e vasculares do treinamento resistido: implicações na doença cardiovascular. Arq Bras Cardiol 2007;89(4):256-62. https://doi.org/10.1590/S0066-782X2007001600008
  34. Xie B, Yan X, Cai X, Li J. Effects of high-intensity interval training on aerobic capacity in cardiac patients? a systematic review with meta-analysis. Biomed Res Int 2017;2017:5420840. https://doi.org/10.1155/2017/5420840