oppose the statement waterboarding can be performed in ways that leave no lasting physical damage requires a reliable medical source which i doubt you will find for the simple reason that it is impossible to perform any physical act of violence in a way that guarantees no physical damage what if the victim has a weak heart or genetic susceptibility to heart attack an accurate statement might be waterboarding may or may not result in lasting physical damage or even death depending on the severity of the attack and victim's constitution and disposition