If you're struggling with fitness, one of the best things to do is spend some time with kids. You'll notice that they move far more than you do. But if you can, it's good to try to keep up with them. They're going to exhaust you, but don't let yourself blame your age for your lethargy. The difference in your energy level isn't all about age, but about socialization.

“Sit down!” “Sit still!” “Can't you just be quiet!” All of these things that we say to our children, we say when we want peace and quiet, or when we ourselves want to rest. But it is often in those moments when it would be good for adults to be active and use that time to exercise their bodies.

And yet, adults often expect children to walk at the same pace they do or to move as quickly as they do. Whether it's putting on their coats or taking a walk, when kids want to take their time, they do.

And that too, is a natural form of body wisdom, because bodies, as you've learned, also need time to use low amounts of energy. So a walk down the block that takes a half hour because of how interesting all the weeds look peeking through the sidewalk cracks? That's natural, too.

So, if you can spend a day or two with some young kids (without a TV nearby, of course), try to keep up with them and, at the same time, try to slow down with them. See how you feel at the end of the day. Chances are you'll feel energized and yet tired. Children, if they haven't yet been overly socialized, move as much as they need to, and when they are given the opportunity, they take great care of their bodies.