I’ve never experienced altitude sickness. I’ve been to Colorado a handful of times, but I didn’t particularly notice the difference. Of course, that doesn’t prevent me from texting a friend before I head into Well-Fit Performance in West Town: “If you don’t see me tomorrow, it’s because I died at altitude training, FYI.”

That might be a tad melodramatic, but as I wait for my class to begin, I’m legitimately nervous that I might puke, or faint, or both, because while I’ve never gotten sick up in the air, I’ve also never done high-intensity interval training at an elevation of 10,000 feet.

Well-Fit, a training center for multisport participants (think triathletes), opened the Midwest’s first altitude room early last year. The 500-square-foot space doesn’t look like anything special: With four treadmills and six bikes, you could easily mistake it for a small cardio gym. But this room has less oxygen, simulating the conditions at 10,000 or even 15,000 feet above sea level. The body learns to absorb and process oxygen better when it’s in short supply, which means athletes who work out like this might then cruise through races in the flatlands.

For a 36-year-old woman who isn’t training for anything in particular, the workout here should still be a greater bang for my exercise buck. Since my body is working extra hard to make up for the lack of oxygen, I’ll torch more calories and get in shape faster — or so I’m told.

My class is led by Well-Fit owner Sharone Aharon, a former member of the Israeli secret service and an eight-time Ironman competitor. He’s fired up — manipulating the air that athletes breathe is his version of fun. Our class consists of three women, and we all choose the treadmills over the bikes. Sharone leads us in 30 minutes of sprint intervals. I notice that maybe my breath seems shallower. “I’m a little gaspy,” I tell Sharone when he asks how I’m feeling. But I also think it might be in my head. If I hadn’t known about the oxygen thing, I’m not sure I would have noticed. My sense is that Sharone may be taking it easy on me — the usual clientele here uses phrases like “threshold pace” and “oxygen saturation” in everyday conversation.

At the end of class, I feel fine — or at least the same amount of fine I feel when I sprint normally. I’m tired and sweaty, but there is no vomiting. There is no fainting. It was, pretty much, a typical workout. If I were looking to qualify for the Boston Marathon, I might stick with it for the month or so it takes to see results, but as a regular gal just trying to stay in shape, I like my oxygen at full blast.

At the end of class, I feel fine — or at least the same amount of fine I feel when I sprint normally. I’m tired and sweaty, but there is no vomiting. There is no fainting. It was, pretty much, a typical workout. If I were looking to qualify for the Boston Marathon, I might stick with it for the month or so it takes to see results, but as a regular gal just trying to stay in shape, I like my oxygen at full blast.