Introduction: High intensity interval training (HIIT) is now recognized in international clinical-based exercise guidelines as an appropriate and beneficial adjunct to moderate intensity continuous training. (1) Moreover, prescribing precise HIIT intensity based on individual capacities and needs is mandatory to optimize results. However, intensity prescription might encounter some obstacles when it comes to implementing pre-training testing. This study showcases individual exercise prescription in a group of ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) patients to achieve progressive increase of functional capacity and therefore – better health and quality of life as primary outcomes.
Patients and Methods: 16 STEMI and NSTEMI patients (age 58 ± 10 years; height 177 ± 9 cm; weight 86.8 ± 15.4 kg; VO2max 19 ± 5.3 ml min-1 kg-1) underwent 12 weeks of supervised cycling HIIT (4x4 min at 85-95% of HRmax) 3 times per week. Functional capacity (VO2max) and all cardiopulmonary parameters as well as HRmax ware assessed by means of the incremental cardiopulmonary test to exhaustion (CPET) every 4 throughout the training program. Individual training zones were prescribed and adjusted according to the parameters obtained in CPET.
Results: There was a good correlation (r= 0.67) between the predicted HRmax and measured HRmax at the beginning of the training period but a weak correlation (r=0.43) at the end of a 12-week training program. The absolute improvement in VO2peak at the end of the 12-week training was 32% (19.2 ± 5.1 vs 25.5 ± 4.9 mil min-1 kg-1, P<.001).
Conclusion: The “dose” of the exercise can be operationalized and monitored using a specific indicator (or set of specific indicators) of internal load as proxy. In this regard, to maximize safety in clinical populations, it is mandatory to precisely adjust pre-exercise screening and regular monitoring. Modifying the exercise prescription by carefully adjusting the external load in relation to internal parameters, can define an optimal dose for this group of patients.