The term ‘gym-penis’ has been trending online, with people sharing their experiences of their penis and/or testicles seemingly shrinking during exercise. Gym-goers are discovering that their penis can look significantly smaller after a workout. Cold temperatures can also have a similar effect, potentially explaining why ‘gym penis’ is particularly noticeable in changing rooms and showers. Nustamante assures: “Once your body cools down, your nervous system settles and blood flow redistributes, the penis typically returns to its usual flaccid appearance. When you should get it checked outHowever, persistent changes to the penis or testicles should be checked by a medical professional.