STRONGER HEART AND LUNG ANATOMY
Both your heart and lungs benefit from progressive and safe overloading, just as your musculoskeletal system does. To achieve 'cardiovascular' overloading, rhythmic movement of your limbs must occur and this should induce some degree of breathlessness and, depending on the intensity, a build-up of lactic acid, usually, in your leg muscles.
N.B. Boxing will also challenge your heart and lungs due to the rapid and rhythmic movements of your upper body.
The really important aspect to achieving safe and effective cardiovascular gains is to monitor your heart rate during various cardiovascular activities. In this way you can challenge your heart and lung anatomy both safely and effectively.