it effectively turned sedentary 55-year-olds into 30-year-olds when viewed through heart activity monitoring equipment.
Being that heart disease is the leading cause of death for most people in the United States, and cardiac strength is inversely correlated with heart disease, it’s probably one of the most significant studies on exercise ever carried out.
It sounds like you have a drastically different experience with exercise than others, to the point that you might want to talk to someone about it? Very few people get as mentally stressed when exercising as you seem to be describing.