Faced with deep winter, the unfortunate question becomes, how bad do the jim-jams have to get to drive us out there where we can do the actual running? All you want is a nice relaxing run, and the atmospherics insist on turning it into the next thing to a polar expedition. Deep winter may not always present the most salutary conditions for runners, but think of it this way: change is what keeps us fresh too. Go for a run, change your life. Sometimes it can work better in February than it does in June.

Circumstances can keep you from running where and when you want, but nothing except lack of training can take away your right to run exactly as hard as you want to. The more you run, the more of this freedom you acquire. That's the beauty part.

Even purely recreational runners can come to know what racers know: that the most enjoyable times in running come when you are teetering on the edge of fatigue but hang on a moment longer, and a moment longer, and at some point discover not only that you can bear it but that you can even pick it up a bit. That is the greatest thrill in endurance athletics – a greater thrill, even, than winning. And it is available to the totally non-competitive runner, so long as you're willing to avail yourself to the opportunity – the freedom – to experiment with levels of fatigue.

Daily exercise dosage: thirty minutes of elevated heart rate, taken daily, a magic bullet against the ills of modern life. That's actually how running starts for most of us. If we progress beyond that formula, it is because we discover an appetite that turns running into something more: a challenge, a security blanket, a fulfillment unavailable in otherwise sedentary lives. Dr. Kenneth Cooper has said that if you're running more than fifteen miles a week, you're running for something other than cardiovascular health. Yes. Exactly.

In recent years I've come to realize that the more of the outdoors I get, the more I want. That alone - that growing appetite for being out in the world - is a debt to running that I can never repay.

If you're having trouble staying motivated, seek an attitude adjustment. Stop thinking of exercise as more of that self-improvement stuff and start thinking of it as rescue: private time, a tranquilizer (and energizer), an antidote for the poisons of modern life. Use exercise that way and you don't have to make yourself do it, you have to ration the dosage.