With my knapsack on my back

Another argument with the health promotion mob; The Conversation, http://theconversation.cmail20.com/t/r-l-ykkufuk-wujjdkdo-b/
An article titled

New study shows more time walking means less time in hospital

The inactive people (taking 4,500 steps per day) averaged 0.97 days of hospital care per year. The more active people (taking 8,800 steps per day) needed only 0.68 days of care per year. 

So to save half a day, 12 hours (assuming that the graph is 24-hour days; if it's working days, of course, 4; could I ask for clarification?) in hospital each year one should walk an extra 244 hours over the year.  If you like walking, that's fine; if you don't, it doesn't really sound the best possible tradeoff. I appreciate that it's supposed to be a proxy for other things, but I'd like to see the correlations. 40 minutes a day, after all, is in one perspective "not much"; on the other, it's one-twenty-fifth of your waking life, or something like three years over a lifetime, not something to be quite so casual about. 

And another request for clarification. The article says that 

The inactive people (taking 4,500 steps per day) averaged 0.97 days of hospital care per year. 

The popups on the actual graph seems to say that people on 4,000 scored 1.18 and people on 5,000 scored 1.08. 

I am actually surprised that the people on 1,000 are as healthy as they are; they're having a quarter of the exercise as the over-80s, which hardly gets them from the couch to the toilet, and there's still no spike.