Omega-3 fatty acids have long been ascribed a positive cardiovascular function. However, the plasma measurements invariably ignore 40% of the blood specimen, cells that engage in continuous exchange with their environment. In our study, we included all components of the circulating blood. Erythrocyte or red-blood-cell (RBC) n-3 fatty acid status has been linked to cardiovascular disease and death. A low omega-3 index is an independent risk factor for cardiovascular disease and mortality. We tested the hypothesis that acute, maximal exercise would influence the relationship between RBC and serum fatty acids. RBC fatty acids profiling was achieved using targeted HPLC-MS mass spectrometry. Healthy volunteers performed maximal treadmill exercise testing using the modified Bruce protocol. Central hemodynamics were monitored and maximal workload was assessed in metabolic equivalents (METs). Venous blood was obtained for RBC lipidomics. With the incremental exercise test, no fatty acid-level variations were found in RBCs, while heart rate and arterial blood pressure increased significantly. No changes occurred in the omega-3 quotient, namely the percentage of eicosapentaenoic acid and docosahexaenoic acid in RBC fatty acids in the RBC membrane. Nonetheless, maximal (13.50 ± 1.97 METs) exercise intensity led to a decrease of RBC lauric acid (C12:0) in the recovery period. These data suggest that despite significant hemodynamic effects, short-term maximal exercise is insufficient to alter RBC n-3 and other fatty-acid status, including the omega-3 quotient, in healthy individuals. RBC lauric acid deserves further scrutiny as a potential regulator of cardiovascular and metabolic functions.
Keywords: Erythrocytes; exercise; fatty acids; lipidomics.
© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.