Objective To compare effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on platelet function in patients undergoing cardiac rehabilitation, as hyper-reactive platelets are involved in atherogenesis and atherothrombosis.
Methods In this single-centre parallel group randomised controlled trial, male patients after an acute coronary syndrome under dual antiplatelet therapy performed MICT or HIIT+MICT for 12 weeks. Main outcome was platelet reactivity measured by the half-maximal concentration (EC50) of platelet agonist thrombin receptor-activating peptide-6 (TRAP-6) in terms of P-selectin expression. EC50 was determined at baseline, after 6 and 12 weeks, each time at physical rest and on exertion.
Results 82 patients were randomised to MICT or HIIT+MICT. Mean (95% CI) baseline EC50values at physical rest were 6.7 µM (6.3 µM to 7.0 µM) TRAP-6. After 6/12 weeks, 36/33 MICT and 34/28 HIIT+MICT patients were examined. HIIT+MICT patients had 0.9 µM (0.4 µM to 1.4 µM)/0.5 µM (−0.1 µM to 1.0 µM) higher EC50values than MICT ones, and the propensity of their platelets to form aggregates with monocytes was significantly lower after 12 weeks. Short-term strenuous physical exertion was generally associated with platelet activation and an EC50reduction of 0.7 µM (0.6 µM to 0.8 µM). HIIT+MICT patients tended to be fitter after 12 weeks. No serious harms were observed.
Conclusions Including HIIT in cardiac rehabilitation seems to confer additional benefits compared with MICT alone, which should be confirmed in clinical trials with hard endpoints. Exertion-induced platelet activation and hyper-reactivity occur despite dual antiplatelet therapy.
Trial registration number NCT02930330; Results.
- cardiac rehabilitation
- cardiac risk factors and prevention
- inflammatory markers
- coronary artery disease
- vascular biology
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Contributors SH established methods, designed the trial, analysed data, prepared figures and wrote the manuscript. AA designed the trial. BF performed platelet function tests. MS-L performed and analysed exercise tests. MH performed and analysed exercise tests. HO supervised exercise training sessions and screened patients for eligibility. AG designed the trial and performed the main statistical analyses. RP designed the trial. IV established platelet function tests. All authors revised the manuscript critically. All authors have given their final approval of the version to be published.
Funding This work was supported by the Austrian Heart Funds and the Medical Science Fund of the Mayor of Vienna (grant number 15136), both granted to SH and the Anniversary Fund of the Austrian National Bank (grant number 15946) granted to IV.
Competing interests None declared.
Ethics approval This trial was approved by the local ethics committee (Federal State Upper Austria, vote E-35–15).
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.