For 26 years as a plastic surgeon, I have given my patients the same advice after surgery: Listen to your body. Pain, fatigue, and swelling are not inconveniences. They are signals. They are the body’s language, guiding us toward healing or warning us when we have gone too far. What I have learned this year, at 65, is how difficult that advice can be to follow. In January, I was training on my Peloton treadmill, preparing for three races scheduled at the start of the year.