The first rule of cross-country skiing is fitness — have it. If your heart is opposed to beating 180 times in one minute, then Nordic skiing might not be for you.

Every time we’ve gone to Nordic centers, with their seemingly gentle, rolling grounds that lack the fight-or-flight slopes the chair lifts climb at resorts, we see those poor people who, avoiding one poison, inadvertently pick another. I’m no good at downhill skiing, they say, so I thought I would try this. If this idea has crossed your mind and you’re not already training for a 10K or triathlon, save yourself the trouble of a day of lactic acid and start your apres-ski early with an Irish coffee in the lodge.

Case in point: the first time I donned my tights for some classic XC skiing (this is a European endurance sport, so Lycra is a prerequisite), I was lifting at the gym three times a week and cycling about as often. I was 24, had visible ab muscles and solid, not saggy, triceps. But when I hit that first oh-so gradual hill on a green trail, I was sucking wind and stripping off clothes in the 30-degree weather.

(I’m pretty sure I sunburned the insides of my nostrils that day. Snow is reflective, I learned.)

This brings me to the second rule of XC skiing, which is going uphill — get used to it. Not only are you required to go uphill, you do so with smoothly waxed planks attached to your feet. If you want to stop to take a break, you have to awkwardly position yourself at an angle that doesn’t destroy the tracks or let you slide backwards. This is only if no one is behind you. So you really just want to keep going up, which is where that high heart rate comes in.

Where do I order that Irish coffee?

Jeremy is an endurance freak of nature. He’s done competitive endurance sports his entire life. So of course, Jeremy read that skate skiing — the ultimate aerobic way to punish yourself on skis, even more so than classic XC — is a great way for cyclists to cross-train in the winter, and was hooked before he’d even tried it. He practically drooled the first time we saw skate-skiers elegantly gliding along the middle of the groomed trails. They’re thin, efficient and graceful, like watching the Tour de France on snow.

The season ended shortly after that first glimpse, and Jeremy never got his chance to skate that winter. So after a four-year exile in Missouri, he had an undeniable jones to get on skate skis when we moved back to Colorado last year. In December, we went to Summit County for a few days, and we took a skate-skiing lesson together.

This brings me to the first rule of skate-skiing, which we learned is balance — have some. Not the yoga kind, where you stand in tree pose for a few minutes. I can do that. This is the sliding, ice skating kind of balance, the kind of balance that requires core strength. If you do not have core strength, you will quickly learn the second rule of skate-skiing, which is look cool — or get out of the way.

Rule #2 is particularly difficult when you’ve just performed a face-plant at the bottom of an embarrassingly short downhill hump, nay, a molehill. I managed this move during our private lesson. Our instructor kindly walked me through pulling the tips of my skinny skis out of the snow and handling my unwieldy poles, which were nearly as tall as me.

It is also hard to abide with Rule #2 when, at the end of the day, fatigued, ankles swelling defiantly against your ski boots, another instructor at the Frisco Nordic Center breezes up to help you (read: take pity on you) because:

“You’re kind of doing a Frankenstein lurching thing here. Try doing this.”

And glides away, poles nowhere to be found, with ease and grace.

So it is with some reluctance that I’m going with Jeremy to Devil’s Thumb Ranch tomorrow. Devil’s Thumb has miles of XC trails. Jeremy can skate to his heart’s content. I’m going to try shuffling along the grooves in classic XC skis again. My ankles will thank me, but I doubt I’ll look cool. There’s a high chance of lurching, even in classic skis, and the Lycra doesn’t fit quite as well as it did when I was 24. But this reminds me of the first rule of getting older:

Who cares?