"The most active group of women spent the equivalent of 420 minutes a week (60 minutes a day) or more engaged in moderate-intensity physical activity."

I did read the article and the primary reported measurement was a total duration over a week which coincidentally could be achieved at 60 mins/day. Frankly, a blanket 60 mins a day seems weird since you need to vary your workout activities. 60 mins a day for me would be complete burnout but I easily out do 420 mins/week.