McLellan, H (2024) Exercise training and Cardioprotection: Interaction with Cardiovascular Risk Factors and Disease. Doctoral thesis, Liverpool John Moores University.

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Abstract

Aims and Methods: Physical activity (PA) and/or exercise training can reduce risk of future cardiovascular events in asymptomatic and individuals with established cardiovascular disease. However, there is large heterogeneity in this response. This thesis aimed to examine some of the factors that may contribute to this. Study 1 was a cohort study including 139,930 individuals looking at the role of moderate-vigorous PA (MVPA) on stroke risk in both medicated and nonmedicated hypertensives vs normotensives (median follow up: 6.75 years). Study 2 was a secondary analysis of markers of cardiovascular function in 338 individuals undergoing supervised exercise training (8-26 weeks) stratified on their baseline endothelial function (FMD%). Study 3 examine the acute effects of moderate-intensity continuous cycling exercise on cerebrovascular function in eight individuals with medicated hypertension (55±6 years) and ten control individuals (54±7 years). Results: Study 1 reported lower Hazard Ratios (0.75, P=0.02) in those who did more (Quartile 3), MVPA moderate-intensity PA compared to the lowest quartile of MVPA. The shape of the dose-response was not different between hypertensives and normotensives, but this relationship may be altered by hypertensive medication. Study 2 demonstrated that exercise training significantly improved physical fitness, BMI, blood pressure and total cholesterol, irrespective of initial baseline endothelial function. Study 3 showed that post-acute exercise, absolute cerebrovascular reactivity decreased by 0.6 cm/s/mmHg in the control group but increased by 1.03 cm/s/mmHg in the medicated hypertensive group (P=0.02) with no change in peripheral endothelial function (FMD%). Conclusion: (i) MVPA reduces stroke risk in the total population, which is not affected by the presence of hypertension. Use of anti-hypertensive medication may interfere with the impact of MVPA on stroke risk. (ii) Individuals with reduced and preserved a priori endothelial function status can obtain benefits from exercise in terms of risk factor modification and fitness change. Therefore, exercise has the potential to be beneficial in all clinical groups. (iii) following acute exercise cerebrovascular function appears to be different in normotensive vs hypertensive individuals (iv) overall, exercise is cardioprotective in healthy individuals and those with cardiovascular risk factors, but further work is needed to determine factors that underpin responsiveness to exercise training including the acute stimulus and role of medication.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Hypertension; Cardiovascular Physiology; Cerebrovascular Physiology; Endothelial Function; Acute Exercise
Subjects:	R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport & Exercise Sciences
SWORD Depositor:	A Symplectic
Date Deposited:	01 Jul 2024 14:31
Last Modified:	01 Jul 2024 14:31
DOI or ID number:	10.24377/LJMU.t.00023642
Supervisors:	Dawson, E and Thijssen, D
URI:	https://researchonline.ljmu.ac.uk/id/eprint/23642

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