Passage Summary: Mondays are the most common days for heart attacks, which people usually blame on the stress of going back to work. However, even people who don't work—like retirees—are more likely to have heart attacks on Mondays.

Reasoning: Heart attacks peak on Mondays, usually attributed to work-week stress, yet even unemployed retirees show this same Monday spike.

Analysis: We have a classic 'Monday Mystery' here. If the stress of the workweek is the culprit, retirees should be exempt from the Monday spike, yet they aren't. To resolve this paradox, we need a factor that makes Monday stressful or physically taxing for everyone, regardless of whether they have a boss to answer to. Look for an answer that introduces a social or environmental trigger that hits retirees just as hard as the 9-to-5 crowd.