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Running Won't Widen Your Waist: Myth Busted
14 May
Summary
- Running does not cause bulky midsection muscles.
- Aerobic exercise promotes fat loss, not muscle gain.
- Temporary waist changes may be due to inflammation.

Experts are debunking a viral myth suggesting that running causes a wider waist. Fitness influencers have promoted the idea that running builds thicker midsection muscles, leading to a boxier torso. However, scientific evidence indicates this is untrue. Running engages core muscles but not in a way that leads to hypertrophy, or significant muscle bulk, which typically requires heavy resistance and intense, consistent training.
Instead, running is a low-resistance, endurance-based exercise primarily for burning calories. Research suggests regular aerobic activity, including running, generally results in decreased waist size and overall body fat. While elite athletes may have different physiques, their training differs significantly from recreational runners. Any perceived temporary waist increase after a run is likely due to factors like post-run inflammation or water retention, not muscle gain.