Lifestyle Interventions to Improve Cardiorespiratory Fitness and Reduce Breast Cancer Recurrence

Abstract

As patients are living longer after a cancer diagnosis, survivorship is becoming increasingly important in cancer care. The sequelae of multimodality therapies include weight gain and decreased cardiorespiratory fitness, which increase cardiovascular risk. Evidence suggests that physical activity reduces the risk of breast cancer recurrence and death. Avoidance of weight gain after therapy also improves outcomes after a diagnosis of breast cancer. Prospective randomized trials must be performed to determine the benefits of specific physical activity and dietary habits for survivors of breast cancer. This review outlines the important physiologic changes that occur with antineoplastic therapy and the important role of exercise and diet.

Evidence of Better Autonomic, Metabolic and Psychological Profile in Breast Cancer Survivors Meeting Current Physical Activity Recommendations: An Observational Study

“…Exercise training represents a pivotal strategy to reduce cardiometabolic and cancer risk both in primary and secondary prevention [23][24][25][26]. Moreover, in breast cancer survivors, it represents a convenient tool to contrast some important side effects of adjuvant therapy such as increased body weight and increased fatigue [42][43][44].…”

“…We recently reported that normal subjects meeting the recommended weekly activity goals have higher fitness indicators (such as VO2max) combined with evidence of an autonomic shift towards parasympathetic prevalence [20]. Breast cancer survivors are generally characterized by a reduced cardiorespiratory fitness [23,24], and its improvement with an active lifestyle may be responsible for the better autonomic profile contributing to a reduced cardiovascular risk. Another important issue to consider is the important link between stress, fatigue and physical activity.…”

“…These findings are important considering that a growing body of clinical evidence shows that low levels of CRF are associated with a high risk of cardiometabolic disease, all-cause mortality and mortality rates attributable to various cancers and that reduced CRF is a potentially stronger predictor of mortality than established risk factors [21][22][23]. Vice versa, high levels of CRF are associated with a reduction in cardiometabolic diseases and even cancer [23,24]. Multiple studies addressed the relationship between exercise and cancer, demonstrating that to be physically active is of pivotal importance in the primary and secondary prevention of cancer [25,26].…”

Rethinking Rehabilitation

“…In accordance with the Fick principle, the reduced V ˙ o 2peak may be the result of cardiac and "noncardiac" peripheral factors that result in decreased convective and diffusive oxygen transport and reduced oxygen utilization by the exercising muscles. 12,41 Specifically, evidence to date suggests that the lower V ˙ o 2peak is due to a lower peak exercise cardiac output 39,45 secondary to a lower peak exercise stroke volume 39,45 and end-diastolic volume index, 45 as peak exercise HR 39,45 and arterial-venous oxygen difference 39 are not significantly different between BC survivors and controls. The finding of normal oxygen extraction despite a lower cardiac output suggests that peripheral vascular and/or skeletal muscle abnormalities that result in decreased muscle oxygen diffusive conductance may also limit V ˙ o 2peak in BC survivors.…”

“…39,40 Accordingly, an important goal is to improve overall health and CRF across the continuum of BC survivorship. 41 A recent scientific statement from the American 44 Exercise testing may be beneficial in identifying initial CRF levels as well as the mechanisms underpinning their reduced CRF. In accordance with the Fick principle, the reduced V ˙ o 2peak may be the result of cardiac and "noncardiac" peripheral factors that result in decreased convective and diffusive oxygen transport and reduced oxygen utilization by the exercising muscles.…”