Breast Augmentation

One-sided swelling after exercise usually points to fluid accumulating within the implant pocket, sometimes called a seroma, or to muscle irritation from repetitive motion aggravating the capsule around the implant. The chest wall and pectoralis muscle take real mechanical load with each running stride, and if there's any low-grade fluid collection or capsule inflammation, that repetitive motion can make it more noticeable. This is worth an in-person exam rather than guesswork. Your surgeon can check for a fluid collection with ultrasound, which also happens to be one of the FDA-accepted methods (along with MRI) for evaluating implant integrity if there's ever a question of rupture. For new fluid buildup appearing well after surgery, your surgeon will also want to rule out BIA-ALCL, a rare implant-associated lymphoma, especially if you have textured implants. A short break from running often lets things settle down if it's simply reactive swelling. If the swelling is new, rapidly progressive, or accompanied by pain or firmness, don't wait it out. See your plastic surgeon promptly for an exam and imaging to sort out fluid, capsule issue, or implant problem.