Author(s): WANG, J., KHOR, W., Institution: CHANG GUNG UNIVERSITY, Country: TAIWAN, Abstract-ID: 430

INTRODUCTION:
Hypertension is a major risk factor for cardiovascular diseases. Ischemic preconditioning (IPC) has evolved from a pre-exercise ergogenic tool to a medical cardioprotective strategy. Therefore, this study aims to compare the effects of different IPC regimens on hemodynamic properties and cardiovascular protection to determine the optimal exercise strategy for individuals with prehypertension.
METHODS:
Twenty sedentary men (10 with prehypertension and 10 with normal blood pressure) underwent IR5 (5x3-minute bilateral limb block at 220 mmHg), IR2 (2x3-minute bilateral limb block at 220 mmHg), and IM2 (2x3-minute 30% maximal voluntary contractions) in randomized order before a submaximal (70%VO2max) exercise test. The exercise responses of heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and vastus lateralis muscle oxygenation, including Δdeoxyhemoglobin (ΔHHb), Δtotal hemo-globin (ΔtHb), and Δtissue saturation index (ΔTSI) were determined in this study.
RESULTS:
Compared to IR2 and IM2, IR5 significantly reduced the exercise-induced increase in SBP. Furthermore, the reduction in exercise-induced MAP elevation by IR5 was only observed in prehypertensive subjects. In exercise trials, IR5 increased ΔtHb and mitigated the decrease in ΔTSI, but did not alter ΔHHb. Conversely, IR2 and IM2 induced similar deoxygenation during vascular occlusion, but did not affect exercise hemodynamics and oxygenation parameters.
CONCLUSION:
IR5 effectively reduces the exercise-induced elevation of blood pressure and improves muscle oxygenation during exercise. Therefore, IR5 is a safe and effective non-pharmacological strategy for lowering hypertension and reducing cardiovascular risks during exercise in prehypertensive males.