The Bike Goes Nowhere

Hey {{first name | reader}},

It’s Tuesday, which means your weekly fitness check-in. Welcome to Week #36.

I attended my first spin class in three months. The first thing the instructor said was, “Where have you been?”

“Vacation” was the wrong answer. He took it as an invitation to turn up the resistance.

I had talked myself into believing that all those tourist miles were the only cardio I needed. Fifty minutes on a bike to nowhere set me straight.

I was a dedicated runner for many years, and I still have dreams involving 5Ks. Until my Achilles agrees to participate, however, spin class and very short sprints are what I’m left with. There are worse fates.

I’ve been told that an hour of indoor cycling can burn up to 600 calories. I’m sure this is true for someone. It has never been true for me.

An intense fifty-minute class gets me to 400 calories on a good day—or at least persuades my watch to display the number 400. Exercise-calorie estimates are imprecise enough that I’ve stopped treating them as an accounting system.

The number is also the least interesting thing I get from the class.

Cycling lets me reach the intensity of a hard run without repeatedly striking the ground. It works my quads, glutes and hamstrings; the changes in resistance and pace challenge both aerobic fitness and the ability to produce short, hard efforts. My core keeps me stable when the resistance gets heavy, although I would not go so far as to call sitting on a bicycle a full-body workout. My arms remain largely decorative. A 2019 review of the indoor-cycling research found that cycling drove improvements in aerobic capacity, blood pressure, and body composition — though the underlying studies were thin enough that 'promising' is a fairer word than 'proven.'

The greatest benefit may be that I don’t have to think.

The instructor picks the music and tells me when to sprint, when to climb and when to maintain a steady pace. My favorite instructors pick good music and don’t talk much, which allows me to zone out while still doing exactly what I’m told.

Except when I’m visiting my sister in New York, I lift weights alone. Spin class injects a little community into an otherwise solitary training week.¹ I take the same classes at the same times. The instructors recognize me. Some of the other regulars do too. When I disappear for three months, I get questions.

That is accountability without requiring a spreadsheet, a streak or a motivational quotation. I simply have to walk into a room where people expect to see me.

Question: Which is better: indoor or outdoor cycling?

Answer: Like most workouts, the better one is the one you’ll actually do.

Beyond an occasional Bay Wheels rental when I’m in a hurry to cross San Francisco, I don’t ride outside much. Every regular cyclist I know here has been hit by a car, and I have a tendency toward inattention. For me, sticking to indoor cycling is also a longevity strategy.

That said, one of my favorite vacations was a bicycle tour through Tuscany. I ate rich Italian food in copious amounts for a week while cycling more than forty miles a day.²

Indoor cycling is predictable: no traffic, darkness, rain, navigation or surprise potholes. It also makes intervals easy. The instructor can take you from a hard climb to a sprint without waiting for the landscape to cooperate.

Outdoor cycling adds balance, steering, terrain and the pleasure of actually going somewhere. Depending on the route, it may include long stretches of coasting or sustained efforts far beyond the length of a spin class. There is no universal winner on calorie burn; that depends on how long and how hard you ride.

Tuscany wins on scenery. The windowless spin studio wins on not being struck by a delivery truck.

Myth: Spinning will make your legs big.

Reality: It might make them slightly bigger. It probably won’t transform them against your will.

My mother hated indoor cycling because she believed it would give her enormous thighs. No amount of science could persuade her otherwise. Mothers are not always open to peer review.

Cycling can build some muscle, particularly when the resistance and training volume are high. But substantial muscle growth generally requires sustained overload, enough food and—most inconveniently—time. A couple of weekly spin classes are more likely to improve your endurance and make your legs stronger than to produce a dramatic change in their size.

Whether someone considers muscular legs “too big” is not a scientific question anyway. My mother had already reached her conclusion.

Hard intervals rely heavily on carbohydrates, which is good news for those of us who never needed much persuasion to eat pasta.

Cook the pasta in salted water according to the package directions. Add the asparagus or broccoli during the final two to three minutes of cooking.

Before draining, reserve about half a cup of pasta water.

Heat the olive oil in a large frying pan over medium heat. Add the garlic and red-pepper flakes and cook for about thirty seconds, just until fragrant. Add the drained pasta and vegetables and toss. Add a splash of pasta water if it needs loosening.

Finish with Parmesan. This is also good cold, although I usually eat the leftovers directly from the refrigerator while deciding what to make for dinner.³

A 2026 systematic review looked at 21 studies examining why adults keep attending group fitness classes: “Perceived Capability, Social Belonging, and Behavioral Adherence in Adult Group Fitness Classes” (Behavioral Sciences, 2026).

Self-efficacy—roughly, believing that you can keep doing the thing—had the most consistent relationship with attendance. Social connection and instructor behavior also appeared to matter, although the results varied by setting and by how researchers measured them. Enjoyment alone was a less consistent predictor.

The evidence is mostly observational, so it doesn’t prove that knowing the instructor will make you show up. It does, however, provide some scientific support for the class where people ask where you’ve been.

Choose one class and book the same time for the next three weeks.

Not whichever class happens to fit your schedule that day. Pick the one you can realistically repeat—the one where the instructor may eventually recognize you and someone might notice if you skip.

The first goal is not to love every minute. It is to become a person who expects to be there.

Stay strong,

{{first name | reader}}

P.S. The bike may go nowhere, but apparently I have to keep showing up to find out whether I do.