Aerobic exercise and breast cancer survivorship

Breast cancer is the most common malignancy among females. Although considerable progress in disease detection and treatment has greatly improved survival, this entails the endurance of sequential treatment combinations. Such treatments are associated with cancer related fatigue (CRF), a debilitating form of fatigue that often persists for months or years post treatment, and a reduction in cardiovascular health that increases the risk of cardiovascular disease. Such factors, combined with the risk of breast cancer recurrence negatively affect patient survivorship. Consequently, interventions that target fatigue, cardiovascular health and risk of breast cancer hold benefit for this population. Aerobic exercise previously shown to promote cardiopulmonary fitness, reduce fatigue and specific breast cancer risk factors is one such intervention. However, due to a failure within the literature to control exercise intensity, and monitor interim time points rather than pre and post test measures, there is a paucity of data regarding the most appropriate exercise prescription for the patient. Therefore, the purpose of this thesis is to extend the existing body of knowledge with novel data regarding the effectiveness of a standardised aerobic exercise prescription upon survivorship (cardiovascular health, fatigue and breast cancer risk), to help elucidate the benefit of moderate intensity aerobic exercise for this group. Study 1: The aim of this investigation was to examine the feasibility of a progressive, moderate intensity, aerobic exercise intervention at improving cardiovascular health within a healthy subset of the population, to determine if the aerobic exercise intervention would be viable within a group of breast cancer survivors. It also had a secondary aim to investigate if the intervention could be implemented within working hours without disrupting the working day for the promotion of occupational health. As the study demonstrated a significant improvement in peak cardiopulmonary capacity (V0 [sub]2 peak) and submaximal oxygen utilisation, alongside a high adherence to the exercise training, efficacy and feasibility was provided for the use of the exercise intervention in breast cancer survivors to improve cardiopulmonary fitness and cardiovascular health. It also confirmed that this exercise intervention could be incorporated into working hours without disrupting the working day. Study 2: The aim of this investigation was to evaluate the effect of the aerobic exercise intervention upon the cardiovascular health and fatigue of breast cancer survivors. There was a significant improvement in V0[sub]2 peak and a trend for a reduction in C-reactive protein (CRP) indicating that the intervention could provide protection against cardiovascular disease. There was also a reduction in fatigue highlighting improved patient well-being, although there were no significant changes in the pro-inflammatory markers associated with fatigue (lnterleukin-6 and TNF-[alpha]). Regarding exercise prescription, the four week follow up period, in the absence of additional exercise prescription showed that while no deconditioning occurred there were no further adaptations in cardiopulmonary fitness. Study 3: The aim of this investigation was to evaluate the effect ofthe aerobic exercise intervention upon cardiovascular health, IGF-1, IGFPB-3 and the molar ratio in healthy pre-menopausal women. There was a significant improvement in V0[sub]2 peak, submaximal oxygen utilisation, resting heart rate, IL-6, alongside a trend for a reduction in CRP, supporting an improvement in cardiovascular health and a reduction in risk of cardiovascular disease. There was also a significant reduction in IGF-1, but as there was no change IGFBP-3 or the IGF-1:IGFBP3 molar ratio the benefit of the aerobic exercise intervention at improving IGF profile within healthy pre-menopausal women remains equivocal. These investigations provide novel data for the benefit of progressive moderate intensity aerobic exercise upon the survivorship of women who have recovered from breastcancer. In particular, interim time point analysis within all studies highlights the need for progressive aerobic training, to continue adaptation for the optimisation of health related benefit. As moderate intensity aerobic exercise had no adverse effects, and received high study adherence within breast cancer survivors, future research that examines the effect of higher intensity aerobic exercise training is now required to evaluate if there are additional health related benefits for the patient.