To treat a herniated disc with physical therapy, start with gentle stretching exercises to improve flexibility and relieve nerve pressure. Focus on core-strengthening exercises like pelvic tilts and bridges to support the spine. Gradually incorporate exercises that improve posture and stability, such as planks and bird-dogs. Avoid activities that aggravate pain, and apply heat or cold therapy to manage discomfort. Over time, progress to low-impact aerobic activities like walking or swimming to enhance mobility and spine health.