Geert Kleinnibbelink

Chapter 5 130 Our finding contrasts with a previous study that investigated PEH in hypoxia following resistance exercise. 21 In this study, healthy youngmales showed significantly lower SBP and DBP levels 10, 20 and 30minutes post-resistance exercise in hypoxia (FiO2 13.0%) compared to normoxia. 21 A key difference with our study is that they examined resistance exercise, compared to endurance exercise in our study. Whilst this difference in exercise mode may explain cross-study findings, former within-subject comparisons support the hypothesis that the mode of exercise (resistance vs endurance) does not alter the magnitude of PEH. 33, 34 However, none of these previous comparisons have taken hypoxia into account. In addition, in the study of Horiuchi et al. post-exercise recovery was performed under normoxia, making any comparisons with the previous investigations difficult, due to the persistent influence of hypoxic stress on autonomic and haemodynamic post-exercise responses. Future work is required to better understand the potential difference in effect size of PEHbetween the different modes of exercise under hypoxia and recoverymodalities. Correlation post-exercise hypotension versus BP changes to training The anti-hypertensive effects of regular exercise training for the general population are well known. This study further explored the relation between PEH and the long-term benefits of regular exercise training. The decrease of ~5mmHg in mean BP after 12-weeks of exercise trainingmay seemmarginal, but actually exceeds that of most previous studies examining the benefits of exercise training on BP in healthy individuals. 35 Within this context, it is important to realize that larger anti-hypertensive effects may be observed in those with (borderline) hypertension. 35 Importantly, we were able to link PEH, observed during the first session of high-intensity running exercise, to changes in resting BP after 12-weeks of exercise training. This observation provides further support that acute changes in BP after exercise ultimately relate to long-term changes. 8-10 An important addition to this knowledge, is that the correlation disappearedwhenwe related PEH (taken after hypoxic exercise) to post-training BP assessed under normoxia. This suggests that the BP responses to acute and chronic exercise training, despite the similar magnitude of PEH, are related through distinct pathways. From a personalised exercise perspective, this observation means that those with the largest decline in PEH under normoxia, even when exercise training is performed under hypoxia, can expect the largest decline in resting BP (under normoxia). This may contribute to further personalise strategies to lower BP.