I have long known (though I’ve yet to give up trying) that it is almost impossible to motivate smokers to quit for good by regaling them with the health hazards of tobacco. And now I’ve been told by readers of last week’s column, “Even More Reasons to Get a Move On,” that repeated sermons on the health benefits of physical activity may get some folks started but are unlikely to keep them at it.

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And it’s true that for many people, future health benefits may just be too abstract and speculative to overcome inertia and take up walking, running, swimming, cycling or working out in the gym. So here is a little secret. What really keeps us devoted exercisers going, even in the face of myriad obstacles, is much more tangible…Continue