Should 15,000 Steps a Day Be Our New Exercise Target?

Based on our discussion of the Quantified Self and other ways to track data about ourselves, I read this article and found it to be quite relevant (also see other related links).

It begins by noting that the 10,000 daily steps, incorporated as a goal into many activity monitors today, has not been scientifically validated as a way to lessen disease risk. So how much exercise might be needed in order to avoid heart disease has remained very much in question?

In a new study, which was published this month in The International Journal of Obesity, researchers at the University of Warwick in England and other institutions decided to examine postal workers in Glasgow, Scotland.

The Glaswegian mail carriers generally cover their routes on foot, not by driving, and spend many hours each day walking, the scientists knew. But the mail service’s office workers, like office workers almost everywhere, remain seated at their desks during the bulk of the workday.  [So for the same group of employees, there are those who walk a lot and those who sit a lot. -sw]   This sharp contrast between the extent to which the workers move or sit during the day could provide new insights into the links between activity and health, the scientists felt. 

The researchers began by recruiting 111 of the postal-service workers, both men and women, and most between the ages of 40 and 60. None had a personal history of heart disease, although some had close relatives with the condition.  They then measured volunteers’ body mass indexes, waist sizes, blood sugar levels and cholesterol profiles, each of which, if above normal, increases the chances of cardiac disease.

The variations turned out to be considerable. Some of the office workers sat for more than 15 hours each day between work and home, while most of the mail carriers barely sat at all during working hours.   But the greatest benefits came from the most exaggerated amounts of activity. Those mail carriers who walked for more than three hours a day, covering at least 15,000 steps, which is about seven miles, generally had normal body mass indexes, waistlines and metabolic profiles. Together, these factors meant that they had, effectively, no heightened risk for cardiac disease.

The implications for what this means and how to get people to walk 4 miles an hour (and steps to achieve that) are discussed in the article.  

How likely is it that people who think 10,000 steps are hard to do will increase it, when they learn it's not enough?  More importantly, why did the industry think 10,000 steps was a good goal?  Did one company start it and the rest followed?