Exercise Training in Chronic Kidney Disease: Impact on Cardiovascular Risk Factors

Cardiovascular disease is the leading cause of morbidity and mortality in people with chronic kidney disease (CKD). Cardiovascular disease in CKD is usually attributed to traditional cardiovascular risk factors and / or novel risk factors specific to kidney disease. Several risk factors may potentially be modified through exercise training to reduce cardiovascular complications.

The aims of this thesis were to characterise the ExTra CKD population by providing baseline data in terms of demographics, aerobic and functional capacity, cardiac output measurements, markers of inflammation and iron metabolism, to evaluate the reliability of brachial artery flow mediated dilation (BA-FMD) to assess endothelial function, to establish readily available methods in assessing aerobic capacity (VO_2Peak) (a prognostic biomarker of survival in this patient population) and to assess the effects of 12 weeks of aerobic exercise (AE) or combined aerobic and resistance exercise (CE) on four interconnected risk factors namely aerobic and functional capacity, endothelial function, chronic inflammation and iron metabolism.

VO_2Peak values in the present cohort were similar to those reported in cardiovascular disease cohorts and lower than values reported in healthy age matched counterparts (Chapter 3). Additionally, hepcidin-25 (a key regulator of iron homeostasis) and haemoglobin levels in the present cohort were significantly different to age matched controls (Chapter 7). BA-FMD showed good inter-operator reliability with regards to scan interpretation, however no changes were shown following exercise (Chapter 4). Chapter 5 demonstrates that VO_2Peak can be estimated using an incremental shuttle walking test and the Duke Activity Status Index with similar accuracy as expensive laboratory based cardiopulmonary exercise tests.

Estimated VO_2Peak calculated using the equations in Chapter 5 improved following both CE and AE (Chapter 6). Despite the known anti-inflammatory properties of exercise, no changes in inflammatory profile were shown following exercise. Interestingly, hepcidin-25 was reduced following exercise (Chapter 7).