Acute and chronic effects of high-intensity interval and moderate-intensity continuous exercise on heart rate and its variability after recent myocardial infarction: A randomized controlled trial

•High-intensity interval training (HIIT) but not moderate-intensity continuous exercise (MICE) tended to acutely increase heart rate during sleep after a day of training in patients after recent ST-elevation myocardial infarction.•Resting heart rate tended to chronically decrease with MICE but increase with HIIT.•Low-frequency power during standing after an orthostatic challenge was increased with MICE but decreased with HIIT.•Heart rate recovery remained unchanged with MICE group but tended to deteriorate with HIIT.