Matt, Chris, and Don review a new study suggesting chocolate may reduce your risk for atrial fibrillation (and resist the urge to just declare this one causal without ever reading the paper), discuss the difference between observational studies and randomized controlled trials and ask whether Usain Bolt is fast enough to cause a Doppler shift.

Journal club article:

Chocolate intake and risk of clinically apparent atrial fibrillation: the Danish Diet, Cancer, and Health Study