Anatomy of a winter cyclist

With arctic winds and single-digit temperatures, it’s the kind of week that makes most commuters grateful for heated cars and trains. The exception: winter bikers, the brave and brazen few who don’t seem bothered by this frigid weather. They are the holdouts who keep pedaling to work as if their fingers are freezer-proof. But what does it take to commute by bike and arrive with your extremities intact in a week like this?

Kate Ziegler has a few ideas.

On Thursday, easily the coldest morning yet this winter, Ziegler, 29, cycled the four miles from her home in Jamaica Plain to her office near South Station, as she does almost every workday.

“If you dress up to go outside in this weather, you might as well move around while you are out there,” she said.

Ziegler works as an operations coordinator at Mintz Levin, a law firm. For Thursday’s zero-degree ride, she picked from an overflowing drawer of athletic clothes she has assembled over the years.

Let’s start with her head: A balaclava is pretty much non-negotiable. It’s a full-face mask that keeps the skin warm in chilly winds. Also, ski goggles, to keep the eyes thawed.

Then a combination ski and bike helmet, chosen because it has removable padding for added warmth — unlike a regular cycling helmet. Next up (or down, actually): two scarves.

The trick for core and arm warmth? Layers. Lots of them. Close to the skin, topped with a windbreaker jacket, and then an outer shell. On the legs: Ziegler tights, covered with running pants, then covered with snug biking pants.

“All of these should be synthetic, for faster drying,” Ziegler said. “No matter how cold it is, you may break a sweat.” There’s a shower at her office, she added, “but I only need it on hot summer days.”

Ziegler doesn’t like big boots on pedals so she uses nylon sneakers, with a wind protector over them.

For her fingers, Ziegler swears by fleece-lined ski gloves or Lobster Claw gloves (like mittens, but with the index finger free). On Thursday, she slipped in little hand warmers, to give her hands an extra boost. “Good gloves cost around $60. They are the only thing you need to invest in,” she said. “Everything else can be done with layers.”

At work, Ziegler leaves the bike out front and loads herself — and all that gear — into the elevator. In her 38th-floor office, she picks from a collection of business suits. On Fridays, most either go home or to a dry cleaner. “Colleagues are sometimes surprised how well I clean up,” she said, laughing.

Ziegler has been biking year round for eight years. Early on, others at her office would see her in the elevator and send her to the loading dock, thinking she was a bike courier. “I’d respond: No, really, I work here. You have a meeting with me at 11 a.m. Now most people have gotten used to me looking like a ninja.”

“When you bike through the winter,” she adds, “this may be most important: Don’t ever care what you look like.”