Exercise in Patients With Breast Cancer and Healthy Controls: Energy Substrate Oxidation and Blood Lactate Responses

Abstract

The aim of this study was to compare select aspects of exercise energy metabolism in patients with breast cancer with that of healthy controls across a variety of exercise intensities. Posttreated patients with breast cancer were matched with healthy women based on age, physical fitness level, and menopausal status. Subjects participated in low-, moderate-, and high-intensity submaximal exercise sessions that corresponded with 40% of maximal oxygen consumption (Vo 2max ), 60% Vo 2max , and 70% Vo 2max . Oxygen consumption and respiratory exchange ratio were taken during submaximal exercise sessions to determine substrate oxidation rates for carbohydrate (CHO) and fat. Blood lactate and blood glucose were also measured before and after each of the submaximal exercise sessions as indices of CHO metabolism. Results indicate that the patients with breast cancer had a significantly (P ≤ .05) lower CHO oxidation rate and higher fat oxidation rate at all exercise intensities compared with healthy women. The patients with breast cancer had a significantly (P ≤ .05) lower blood lactate response to exercise across all intensities compared with the healthy women. Glucose responses tended (P < .08) to be more elevated in patients with cancer both before and after the exercise sessions. The findings indicate that posttreated patients with breast cancer have augmented fat metabolism and a reduced CHO-based energy metabolism during submaximal exercise. It is unclear whether these changes are the result of the patient's cancer or their treatment regimen for the cancer.

Adrenal Hormone and Metabolic Biomarker Responses to 30 min of Intermittent Cycling Exercise in Breast Cancer Survivors

“…Therefore, the purpose of this study was to compare the catecholamine, cortisol, free fatty acid, glucose, and lactate responses to an acute bout of moderate-intensity intermittent exercise in breast cancer survivors and healthy controls. Whereas the previous studies by Evans et al [11] and Tosti et al [40] show that some aspects of glucose and fat metabolism appear to differ between breast cancer survivors and physically similar healthy controls, they did not investigate physiological mechanisms. Therefore, this current study aimed to expand the metabolic profile that was examined and to explore if changes in free fatty acid, glucose, and lactate levels may be driven by the neuro-endocrine responses of the catecholamines and cortisol.…”

“…For breast cancer survivors however, energy substrate utilization during aerobic exercise appears to differ from those of healthy individuals. Evans et al [11] and Tosti et al [40] found that blood lactate levels (a product of glucose metabolism) were significantly lower in breast cancer survivors compared to physically similar healthy controls across various aerobic exercise intensities. Furthermore, Tosti et al [40] observed that as exercise intensity increased, fat oxidation rates were significantly higher and carbohydrate oxidation rates were significantly lower in breast cancer survivors compared to healthy controls.…”

“…Evans et al [11] and Tosti et al [40] found that blood lactate levels (a product of glucose metabolism) were significantly lower in breast cancer survivors compared to physically similar healthy controls across various aerobic exercise intensities. Furthermore, Tosti et al [40] observed that as exercise intensity increased, fat oxidation rates were significantly higher and carbohydrate oxidation rates were significantly lower in breast cancer survivors compared to healthy controls. The exact mechanisms driving these differing responses are unclear but could be related to cancerassociated endocrine changes in glucose and free fatty acid metabolism.…”

“…Previous work by Evans et al and Tosti et al examined metabolic biomarker responses to 9-min bouts of continuous acute aerobic exercise at 40 %, 60 %, and 70 % of estimated VO 2max in breast cancer survivors and healthy controls [11,40]. Evans et al observed that breast cancer survivors exhibited significantly lower blood lactate levels in response to the exercise bout at 70 % of esti-mated VO 2max , whereas Tosti et al observed that post-exercise blood lactate levels in the breast cancer survivors were significantly lower lactate levels across all 3 exercise intensities [11,40]. Moreover, Tosti et al reported that the breast cancer survivor group experienced significantly higher lipid oxidation and lower carbohydrate oxidation rates across all 3 exercise intensities, and that breast cancer survivors displayed less of a decrease in blood glucose levels post-exercise compared to controls [40].…”

Effects and potential mechanisms of exercise training on cancer progression: A translational perspective

“…As summarized in Table 3 and 24 studies to date have investigated the effects of structured exercise training on changes in circulating concentrations of host-related factors in persons with cancer (Allgayer et al, 2004, 2008a; Evans et al, 2009; Fairey et al, 2003, 2005a,b; Galvao et al, 2010; George et al, 2010; Irwin et al, 2006, 2007, 2005, 2009; Janelsins et al, 2011; Jones et al, 2012b; Ligibel et al, 2008; Na et al, 2000; Payne et al, 2008; Pierce et al, 2009; Schmitz et al, 2005; Segal et al, 2003, 2009; Tosti et al, 2011; Yuasa et al, 2009; Zeng et al, 2011). …”