Effectiveness of high intensity interval training on cardiorespiratory fitness and endothelial function in type 2 diabetes: A systematic review

Christos Kourek; Eleftherios Karatzanos; Vasiliki Raidou; Ourania Papazachou; Anastassios Philippou; Serafim Nanas; Stavros Dimopoulos

doi:10.4330/wjc.v15.i4.184

Effectiveness of high intensity interval training on cardiorespiratory fitness and endothelial function in type 2 diabetes: A systematic review

World J Cardiol. 2023 Apr 26;15(4):184-199. doi: 10.4330/wjc.v15.i4.184.

Authors

Christos Kourek^{1

2}, Eleftherios Karatzanos¹, Vasiliki Raidou³, Ourania Papazachou⁴, Anastassios Philippou^{1

5}, Serafim Nanas¹, Stavros Dimopoulos^{1

6}

Affiliations

¹ Clinical Ergospirometry, Exercise and Rehabilitation Laboratory, 1 Critical Care Medicine Department, Evangelismos Hospital, Athens 10676, Greece.
² Department of Cardiology, 417 Army Share Fund Hospital of Athens, Athens 11521, Greece.
³ Clinical Ergospirometry, Exercise and Rehabilitation Laboratory, National and Kapodistrian University of Athens, Athens 10676, Greece.
⁴ Department of Cardiology, "Helena Venizelou" Hospital, Athens 10676, Greece.
⁵ Department of Physiology, School of Medicine, National and Kapodistrian University of Athens, Athens 11527, Greece.
⁶ Cardiac Surgery Intensive Care Unit, Onassis Cardiac Surgery Center, Athens 17674, Greece. stdimop@med.uoa.gr.

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic syndrome characterized by insulin resistance and hyperglycemia that may lead to endothelial dysfunction, reduced functional capacity and exercise intolerance. Regular aerobic exercise has been promoted as the most beneficial non-pharmacological treatment of cardiovascular diseases. High intensity interval training (HIIT) seems to be superior than moderate-intensity continuous training (MICT) in cardiovascular diseases by improving brachial artery flow-mediated dilation (FMD) and cardiorespiratory fitness to a greater extent. However, the beneficial effects of HIIT in patients with T2DM still remain under investigation and number of studies is limited.

Aim: To evaluate the effectiveness of high intensity interval training on cardiorespiratory fitness and endothelial function in patients with T2DM.

Methods: We performed a search on PubMed, PEDro and CINAHL databases, selecting papers published between December 2012 and December 2022 and identified published randomized controlled trials (RCTs) in the English language that included community or outpatient exercise training programs in patients with T2DM. RCTs were assessed for methodological rigor and risk of bias via the Physiotherapy Evidence Database (PEDro). The primary outcome was peak VO₂ and the secondary outcome was endothelial function assessed either by FMD or other indices of microcirculation.

Results: Twelve studies were included in our systematic review. The 12 RCTs resulted in 661 participants in total. HIIT was performed in 310 patients (46.8%), MICT to 271 and the rest 80 belonged to the control group. Peak VO₂ increased in 10 out of 12 studies after HIIT. Ten studies compared HIIT with other exercise regimens (MICT or strength endurance) and 4 of them demonstrated additional beneficial effects of HIIT over MICT or other exercise regimens. Moreover, 4 studies explored the effects of HIIT on endothelial function and FMD in T2DM patients. In 2 of them, HIIT further improved endothelial function compared to MICT and/or the control group while in the rest 2 studies no differences between HIIT and MICT were observed.

Conclusion: Regular aerobic exercise training has beneficial effects on cardiorespiratory fitness and endothelial function in T2DM patients. HIIT may be superior by improving these parameters to a greater extent than MICT.

Keywords: Cardiorespiratory fitness; Endothelial function; Exercise; High intensity interval training; Peak VO2; Type 2 diabetes mellitus.