poor cardiovascular reaction, intense sweating, shortness of breath are all verry dangerous. i got all of these every time. i think keeping healthy and having a general sence of well being is a must for safe steroid use. i cant give you a real scientific explination as to what tren does to cause these symptoms. but i bet you cant tell me one reason why it would be ok, safe, or healthy for a 30 yo man to be out of breath from walking out to his truck. and sweating from sitting in his 68 digree house whatching tv.