Effects Of High-Intensity Interval Training On Myocardial Oxygen Consumption In Young Men

In recent years, researches suggest that high-intensity interval training (HHT) has superior effects on improving cardiopulmonary fitness in patients with cardiovascular diseases compared with moderate-intensity continuous training (MICT), and it shows better time-efficiency and compliance outcome. However few relevant researches have been done in domestic field of cardiac rehabilitation. The purpose of this study is to observe cardiovascular reactivity, myocardial oxygen consumption and the fatigue degree of young healthy men during HIIT, and make a preliminary discuss on exercise tolerance issues.Methods:16healthy young men were enrolled (age23.3±2.3years). After treadmill test and maximal aerobic power test, all subjects completed one session of HIIT and one session of MICT on different days. In order to eliminate the potential impact of training sequence, half of the subjects were randomly selected to train in different sequence. HIIT intensity was set at100%maximal aerobic power, with15s/15s training and interval ratio, total exercise time32min exclusive of warm-up and cool-down phase; MICT intensity was set at70%heart rate reserve level with energy consumption equal to HIIT session. During the two training sessions heart rate (HR), blood pressure (BP), oxygen saturation (SaO2), Borg's score were recorded and percentage of heart rate reserve (%HRR), rate-pressure product (RPP) were calculated for later data analysis.Results:%HRR during HIIT was68.0%±8.9%(95%CI:66.9%～69.1%), which was at the same level with MICT (p>0.05);2. Systolic blood pressure during HIIT sessions was significantly lower than MICT (140.9±15.2mmHg vs.154.7±14.6mmHg, p<0.001);3. RPP in HIIT was significantly lower than MICT (20971.3±3282.1vs.23393.5±2678.4, p<0.005);4. SaO2during HIIT kept above the95%level, no significant difference was found between the two training sessions (97.0%±0.9%vs.96.8%±0.8%, p>0.05);5. No significant difference in Borg's score between the two training sessions (15.0±1.5vs.14.2±1.7, p>0.05). Conclusion:HIIT induces lower BP level and myocardial oxygen consumption compared with MICT, which prompted that HIIT might be more tolerable than MICT.