Roam has two treadmills, bikes, rowing and elliptical machines and a convex-shaped treadmill called Skillmill. Credit: Washington Post.

Of all the reasons to sweat at an airport, Baltimore-Washington International Marshall Airport now offers a good one.

Roam Fitness recently opened its first location in BWI's new D/E Connector, which serves domestic and international passengers. The company plans to expand nationwide, likely starting with Charlotte, Pittsburgh and Atlanta; memberships will include access to all locations.

"The next phase is educating the consumer about how it works and how it fits into their travel schedule," said co-founder Ty Manegold. He noted that BWI already prioritizes health and fitness, offering healthy dining options, a bike path and rentals, and the BWI Cardio Trail.

Early one Thursday morning, I headed to BWI with a carry-on-sized backpack to simulate a pre-flight workout.

Roam, located beyond security, is about the size of a typical airport retailer or larger-than-average hotel gym. At the front desk, I signed up for a daily membership on their iPad, which savvy travelers can do ahead of time. Through March, a day pass costs $25, month pass $150 and annual pass $500. Regular pricing begins in April at $40 a day, $175 a month and $600 a year.

"The time is 6:30," the attendant said. "What time would you like me to book your shower?" He reserved a time and assigned me an overhead compartment-sized locker with USB and electrical chargers.

The most common question from passersby: "What happens when I get all sweaty?" Roam has an answer for that, and seemingly everything else.

Loaner clothing and shoes from Lululemon and Brooks come with each membership. You're on your own for socks, which they sell, along with a small selection of clothes if you're squeamish about communal gear.

When the attendant showed me apparel options on the iPad - as though I were shopping - I was happy to select cropped pants, a tank and sneakers in my size. (You can borrow a sports bra too, but I BYO'd.) Before handing me the rented gear, he scanned electronic chips sewn in each item, linking them to my account in case they ended up in my backpack.

Roam has enough equipment for a legit workout, whether you're up for hard-core training or physical therapy. Cardio options include two treadmills, recumbent and standard bikes, rowing and elliptical machines, and a human-powered, convex-shaped treadmill called Skillmill. The gym also has dumbbells from five to 50 pounds (embedded with chips so don't attempt to walk off with these either), a TRX system, yoga mats, Bosu balls, medicine balls, plyometric boxes (used in CrossFit), foam rollers and stretchy tubes.

During my workout, I had the gym to myself, but countless passengers were curious enough to stop by the front desk. Shannon Toback, an Olympic weightlifter who lives in Baltimore, loved the concept. She flies once a month and said she would consider working out before a flight. "I could have trained this morning at 5 a.m., but you don't know what you'll run into with traffic and security," she said. When I told her my day pass included Lululemon clothing, her face lit up. "Offering to dress you if you don't have gear - that's a game-changer."

After my workout, I found my name on a screen by one of the four private shower rooms. Each has a Kohler toilet with a remote controlled bidet and seat-warmer and an automatically lifting cover.

Amazon's Alexa keeps track of your 15-minute time slot (and will tell you the weather or just about anything else you ask). I found the one hook insufficient for my coat, clothes and complimentary towel, and I learned the hard way that setting items on the mind-of-its-own toilet cover isn't a solution.

If you're not careful, you could spend the entire time playing with the toilet and talking to Alexa.

Roam has deodorant, shaving products, mouthwash and cruelty-free shower products and lotion. In the unisex, shared vanity area, I used the hair dryer while an attendant vacuum-sealed my sweaty sports bra and socks into a Ziploc pouch.

She handed back something that looked like it belonged in my freezer but would certainly contain any odor on a flight. I tossed it in my backpack and headed out to the terminal, feeling energized from my workout, refreshed from my shower and sad only that I wasn't boarding a flight to a faraway land.