So, speculating on the cardiopulmonary details involved, but ima take a stab at some basics. PEs are clots that have traveled to the lungs. Those clots prevent blood flow. Blood flow pools and becomes stagnant depriving O2 to the lung tissue. Also, the blood backs into the heart, which affects the contractility of the heart and can limit the delivery of O2 to the coronary arteries that feed the heart tissue. I am fearful that being medically cleared does not mean having lungs that perfuse properly and heart tissue that contracts with a normal ejection fraction. TK has had a major cardiac event. Is it possible that we could think of it as having a heart attack?? Again not certain, but these responses that she is lazy, she needs to do HIIT, she needs to watch what she eats, or whatever. It may be she is doing the absolute best she can as she is limited by actual structural damage. These posts go beyond insulting and posters might want to think twice about what they say.