Christopher J. Ruhm is an American economist, academic and author. He is a professor of public policy and economics at the University of Virginia and is a professor emeritus at the University of North Carolina at Greensboro.[1] (wikipedia)
When the economy heats up, people often end up working more overtime.
Heart attack fatalities rise when the economy strengthens.
During that period of time chances are you are working so much you are not exercising, haven't had a chance to join a gym, you're eating out a lot, maybe smoking more.
This is a group that's more heavily involved in the workforce and may be more affected by changes.
