Geert Kleinnibbelink

Chapter 5 116 ABSTRACT Background and objectives. Acute exercise leads to an immediate drop in blood pressure (BP), also called post-exercise hypotension (PEH). Exercise in hypoxia is related to additional vasodilation, potentially contributing to more profound PEH. Therefore, we investigated the impact of hypoxia versus normoxia on the magnitude of PEH. Secondly, we examined whether these changes in PEH relate to the BP-lowering effects of 12-week exercise training under hypoxia. Methods . In this prospective study, twenty-one healthy individuals (age 22.2±3.0 years, fourteen male) performed a 45-minute high-intensity running exercise on two different days in a random order, under hypoxia (fraction of inspired oxygen (FiO 2 ) 14.5%) and normoxia (FiO 2 20.9%). BP was examined pre-exercise (t=0) and at t=15, t=30, t=45 and t=60min post-exercise. Afterwards, subjects took part in a 12-week hypoxic running exercise training program. Resting BP was measured before and after the 12-week training program. Results . Acute exercise induced a significant decrease in systolic BP (SBP, P=0.001), but not in diastolic BP (DBP, P=0.113). No significant differences were observed in post-exercise BP between hypoxic and normoxic conditions (SBP, P=0.324 and DBP, P=0.204). Post-exercise changes in SBP, DBP and MAP significantly correlated to the 12-week exercise training- induced changes in SBP (r=0.557, P=0.001), DBP (r=0.615, P < 0.001), and MAP (r=0.458, P=0.011). Conclusion . Our findings show that hypoxia does not alter the magnitude of PEH in healthy individuals, whilst PEH relates to the BP-lowering effects of exercise. These data highlight the strong link between acute and chronic changes in BP.