A Comparison of Hemodynamic Responses to Isometric and Aerobic Exercise: A Randomized Crossover Controlled Study

Introduction Isometric handgrip (IHG) exercise training significantly reduces blood pressure (BP). However, the prescription of isometric exercise remains poor, with continued concerns over safety. This study directly compares real-time hemodynamic responses between isometric and traditionally prescribed aerobic exercise when performed at commonly prescribed and comparable intensities. Methods Seventeen male participants (18–35 yr) were randomized in a crossover study design into aerobic (AER = cycling, 6 metabolic equivalents (METs)) and alternating IHG exercises (4 × 2 min, 30% maximal voluntary contraction). Participants completed three sessions on separate days within 1 wk. After a 1-wk washout, participants crossed over to the opposite exercise arm. Bilateral resting and exercise BP measures were collected at minutes 1, 4, 7, and 10 during exercise and minutes 2, 5, 10, 20, and 30 post-exercise using validated automated sphygmomanometers. Results Systolic BP (SBP), pulse pressure, and rate pressure product (RPP) were higher during AER compared to IHG exercise (P < 0.01), whereas diastolic BP (DBP) was higher during IHG compared to AER exercise (P < 0.01). These findings show that IHG exercise elicits a significantly lower myocardial workload (RPP) compared to AER (P < 0.05). Despite variations in SBP and DBP changes during rest to peak exercise, responses remained within exercise termination criteria. No hypotension was observed for either exercise mode across testing sessions. Conclusion Overall, this study provides additional evidence to encourage the prescription of isometric exercise and further endorsement for its adoption into clinical practice as an exercise mode for managing blood pressure. Given the elevated DBP during IHG exercise, further investigation of end-diastolic left ventricular function is recommended before generalizations about safety can be made.