Every week, Gretchen Reynolds single-handedly influences how millions of Americans work out. In her popular New York Times column, she debunks myths, spurs conversation, and stirs controversy by questioning widely held beliefs about exercise.

Here, Reynolds consults experts in a range of fields to share paradigm-shifting findings that were previously only available in academic and medical journals, including: 

·        20 minutes of cardio is all you need (and sometimes six minutes is enough)

·        Stretching before a workout is counterproductive

·        Chocolate milk is better than Gatorade for recovery