Running is one of the few habits that upgrades nearly every system in your body at once. With each stride you’re training your heart to pump more efficiently, sweeping fresh oxygen through your lungs, and challenging muscles and joints so they grow stronger and more resilient. Scientists now see those miles etched at the cellular level too: regular runners tend to have longer telomeres, a sign their cells are ageing more slowly, and studies show just a couple of hours of steady jogging a week can slash cardiovascular‑death risk. Yet the gains aren’t merely physical—running lights up the brain’s reward circuitry, flooding you with endorphins and endocannabinoids that dial down stress, lift mood, and sharpen memory, benefits that accumulate into healthier cognition as the years pass. Factor in steadier blood‑sugar control and a tougher immune system, and running stands out as an extraordinarily efficient prescription for a longer, livelier life.