Why These 3 Simple Pinterest-Popular Fitness Rules Actually Work

Do a quick search for "fitness" on Pinterest and scroll through and you'll likely see tons of pins that have been circulating for years with thousands of share that promote the same fitness rules: never miss a Monday, never go 3 days without exercise, and work out at least 3 days a week (oh, and there's a fourth one that's more of a motivational tool and less of a rule: never give up).