The physical stress of marathon running can promote exercise-induced muscle damage, reducing muscle force production, elevating blood cytokines, and driving systemic inflammation. Consequently, despite having high cardiorespiratory and neuromuscular fitness, marathon runners are susceptible to lower extremity muscle injuries, cardiac dysfunction, and arrhythmia, particularly as running intensity escalates. A recent study shows that supplemental omega-3 fatty acids ameliorate some of the harmful effects of endurance running.

The study involved 24 male long-distance runners. Half of the runners received 3,000 milligrams (mg) of omega-3s (852 mg EPA; 1,602 mg DHA) daily for three weeks, and the other half took a placebo. After the third week of supplementation, the participants performed a downhill running exercise test. The researchers measured the participants' cardiac markers, inflammatory cytokines, and blood lipids and assessed their Omega-3 Index, a measure of omega-3 concentrations in red blood cell membranes.

They found that the participants' Omega-3 Indices increased from 3.9 to 4.8, roughly 23 percent relative to baseline when they took supplemental omega-3s. Markers of cardiac injury (troponin and creatine kinase isoenzyme MB) and the inflammatory cytokine TNF-alpha decreased. Participants' HDL cholesterol levels also increased.

These findings suggest that supplemental omega-3s ameliorate some of the harmful effects of endurance running, possibly due to omega-3s' potent anti-inflammatory properties. Learn more about the health effects of omega-3s in this episode featuring Dr. Bill Harris.