Effect of self-tailored high-intensity interval training versus moderate-intensity continuous exercise on cardiorespiratory fitness after myocardial infarction: A randomised controlled trial.

Marcin T; Trachsel LD; Dysli M; Schmid JP; Eser P; Wilhelm M

Annals of Physical & Rehabilitation Medicine. 65(1):101490, 2022 Jan.
VI 1

BACKGROUND: Whether high-intensity interval training (HIIT) is more
efficient than moderate-intensity continuous exercise (MICE) to increase
cardiorespiratory fitness in patients with acute coronary syndrome at
moderate-to-high cardiovascular risk is controversial. The best approach
to guide training intensity remains to be determined.

OBJECTIVE: We aimed to assess intensities achieved with self-tailored
HIIT and MICE according to perceived exertion and to compare the effect on
cardiorespiratory fitness in patients early after ST-elevation myocardial
infarction (STEMI).

METHODS: We included 69 males starting cardiac rehabilitation within 4
weeks after STEMI. After a 3-week run-in phase with MICE, 35 patients were
randomised to 9 weeks of HIIT (2xHIIT and 1xMICE per week) and 34 patients
to MICE (3xMICE). Training workload for MICE was initially set at the
patients’ first ventilatory threshold (VT). HIIT consisted of 4×4-min
intervals with a workload above the second VT in high intervals. Training
intensity was adjusted weekly to maintain the perceived exertion (Borg
score 13-14 for MICE, >=15 for HIIT). Session duration was 38min in both
groups. Peak oxygen consumption (VO2) was measured by cardiopulmonary
exercise testing pre- and post-intervention.

RESULTS: Both groups improved peak VO2 (ml/kg/min) (HIIT +1.9, P<0.001;
MICE +3.2, P<0.001, Cohen’s d -0.4), but changes in VO2 were not
significantly different between groups (P=0.104). Exercise regimes did not
differ between groups in terms of energy expenditure or training time, but
perceived exertion was higher with HIIT.

CONCLUSIONS: Self-tailored HIIT was feasible in patients early after
STEMI. It was more strenuous but not superior nor more time-efficient than
MICE in improving peak VO2.