Writers: take this health challenge & increase your productivity

I find that whenever I start slacking off the daily exercise ("I have too much WORK to do…"), I inevitably start feeling more and more tired and uninspired. I'm trying to get in the habit of doing a power walk a day — by "power walk," I mean a walk that is brisk enough to get me slightly out of breath and sweaty (though the latter's not hard to do in the recent Toronto heat wave, ugh). I used to run, but some knee problems scared me into a lower impact exercise.

Some days, though, I get so...