Does Swimming Make You a Better Runner? What the Research Shows

Distance running is mostly an aerobic sport. Your performance is tied closely to how well your heart, lungs, and blood deliver oxygen to working muscles, often measured as VO2 max. Swimming trains that same central system hard. When you swim with effort, your heart rate climbs, your cardiovascular system adapts, and many of those adaptations, including increased blood volume and a stronger heart, carry over to any aerobic activity, running included.