Acute cardiopulmonary responses to strength training, high-intensity interval training and moderate-intensity continuous training

PurposeLong-term effects of exercise training are well studied. Acute hemodynamic responses to various training modalities, in particularly strength training (ST), have only been described in a few studies. This study examines the acute responses to ST, high-intensity interval training (HIIT) and moderate-intensity continuous training (MCT).MethodsTwelve young male subjects (age 23.42.6years; BMI 23.71.5kg/m(2)) performed an incremental exertion test and were randomized into HIIT (4x4-min intervals), MCT (continuous cycling) and ST (five body-weight exercises) which were matched for training duration. The cardiopulmonary (impedance cardiography, ergo-spirometry) and metabolic response were monitored.Results Similar peak blood lactate responses were observed after HIIT and ST (8.5 +/- 2.6 and 8.1 +/- 1.2mmol/l, respectively; p=0.83). The training impact time was 90.7 +/- 8.5% for HIIT and 68.2 +/- 8.5% for MCT (p<0.0001). The mean cardiac output was significantly higher for HIIT compared to that of MCT and ST (23.2 +/- 4.1 vs. 20.9 +/- 2.9 vs. 12.9 +/- 2.9l/min, respectively; p<0.0001). VO2max was twofold higher during HIIT compared to that observed during ST (2529 +/- 310 vs. 1290 +/- 156ml; p=0.0004). Among the components of ST, squats compared with push-ups resulted in different heart rate (111 +/- 13.5 vs. 125 +/- 15.7bpm, respectively; p<0.05) and stroke volume (125 +/- 23.3 vs. 104 +/- 19.8ml, respectively; p<0.05).Conclusions Despite an equal training duration and a similar acute metabolic response, large differences with regard to the training impact time and the cardiopulmonary response give evident. HIIT and MCT, but less ST, induced a sufficient cardiopulmonary response, which is important for the preventive effects of training; however, large differences in intensity were apparent for ST.