When he exercised, Mark Nachtsheim tried to ignore the tightness he felt in his throat and the difficulty he had breathing.

 

At 47, the Gnesen Township man knew he was in good condition. He ran five miles four times a week. He lifted weights. A volunteer on the coaching staff of Duluth East High School’s football team for more than a decade, he was studying for a new career as a strength and conditioning specialist. He never smoked. His family had no history of heart disease. He had high cholesterol, but given his overall health his doctor didn’t see it as a major concern.

 

But that tightness didn’t let go.