My parents recently bought a huge trampoline for their back yard. If anyone asks, the party line is that it's for my nine-year-old to enjoy. But, being a responsible parent, I couldn't just turn my son loose on it without testing it to make sure it was safe. So I did my duty-I climbed up with him and jumped.

Ah, a trampoline. No matter how old you are, it takes you back to your childhood. And since my childhood involved fair amounts of gymnastics and cheerleading, I dug through my memory for some jumps and twists from the old days. Though I most certainly looked as out of practice as I was, I was quite happy to leap and bounce around gracelessly.

This lasted for all of five minutes. Panting and gasping for breath, I held onto my side, which was quickly developing a cramp, and climbed right off the darned thing. "This-is-harder-than-I-remember," I puffed to my mother.

Meanwhile, my son-who has the staggering ability to run for miles without stopping, a talent he inherited from my father and which, unfortunately, skipped a generation-was still going strong.

That's when I made the grim decision to take up exercise again.

I do have a fitness routine, but it doesn't involve sweating, which means it does absolutely nothing exercise is supposed to. You see, I have temperature issues; I'm either freezing or sweating, and there's not a lot of in between. This is a common source of amusement for my family; my father jokes that 72 degrees is too cold for me and 73 degrees is too hot. Well, maybe it's less of a joke and more of a statement of fact.

So to get around the whole sweating thing, I took up Pilates a couple of years ago. I can't recommend it highly enough. You just lie on the floor. I want to kiss the man who thought it up.

It's fairly common knowledge that doctors recommend a cardiovascular component as part of an exercise regime, but I really wasn't interested. I had my Pilates, and I didn't want to lose weight, so why bother? After my defeat at the hands of the trampoline, however, I was willing to give aerobics another try.

I have plenty of fitness videos gathering dust in my house, but like most women, I decided I needed to spend money on something new to kick this whole thing off right. So I bought circuit-training videos that alternate weights and aerobics. Even though this particular series of videos is known for its difficulty, I was pretty sure it wasn't anything I couldn't handle.

This might have been the most wrong I've ever been in my life.

I popped the first video into the player and followed along with the warm up. Five minutes into the warm-up-the warm-up!-I had to stop. Not just take a breather; I had to stop entirely. I was stunned and deeply, completely humbled.

But the worst was yet to come. The next day, I rolled out of bed and was only able to hold in a scream because I didn't want to frighten my still-sleeping child. My legs, my arms, and some muscle in my back that I don't even think has a name-everything was excruciatingly sore.

What I learned from this is that just because your pants fit doesn't mean you can avoid exercise. But that's not the lesson I want to pass along. No, my advice to anyone not currently exercising is-don't start. Because once you start, you know how far you have to go to get in shape. Whereas if you're a couch potato, you can pretty easily convince yourself that, despite all evidence to the contrary, you're probably already in pretty good shape. Which really is not the case.

So if you're already exercising, good for you. If not, grab another bag of Doritos and continue your blissful ignorance. But that's just my advice; you might want to get a second opinion on that. TPW