The cardio guide

How do you get fit on a bike, indoors and out?

By GyroscopeUpdated November 15, 20267 sources

Ride at a pace where you can talk but not sing, and count every minute toward your week. On flat ground the CDC counts riding under 10 mph as moderate and anything faster as vigorous. Once a week, make a ride hard with a few short sprints, which a stationary bike makes easy. Ride to work if you can, wear a helmet, and lift weights too, because a bike does little for your bones.

People tend to think about cycling in one of two ways. Either it’s the serious kind, with clip-in shoes and 50-mile Sunday rides, or it’s a gentle pedal that barely counts. Most riding sits in between, and it’s some of the most useful exercise there is, since you can do a lot of it without pounding your knees and it gets you places. The catch is that a bike makes it easy to coast, so you have to know what effort you’re at.

How hard is a bike ride?

The CDC uses speed. “Bicycling slower than 10 miles per hour on level terrain” is moderate, and “bicycling faster than 10 miles per hour” is vigorous. Hills, wind and a heavy bike move that line, so the talk test is still the better guide on any given day.

The Compendium of Physical Activities measures how hard things are in METs, the energy of an activity against sitting still. Here’s where cycling falls in its 2024 edition.

A leisurely 9.4 mph ride is 5.8 METs, comfortably brisk. A general session on a stationary bike is 6.8, and riding to work at your own pace is 6.8, both into the range where a minute counts as two. Even an e-bike with high assist, the setting where the motor does most of the work, is 4 METs, still inside the moderate band. On light assist it’s 6.

Does riding to work count?

It counts, and it looked like one of the best ways to get your minutes. In 2017, researchers followed 263,450 UK adults for about 5 years and compared how they got to work. People who cycled had 41% lower risk of dying from any cause than people who drove or took public transport, and lower rates of heart disease and cancer too.

In a separate study of 80,306 British adults, people who cycled for exercise had 15% lower risk of death than people who didn’t. Both studies followed people who chose to cycle, so part of the difference may come from the kind of people who ride. But a commute has a big advantage over a gym session: you do it whether you feel like it or not.

What should you do on a stationary bike?

Most indoor riding is steady, and that’s fine. A stationary bike also happens to be the best tool for short hard efforts, because there’s no traffic, no hill to find and nothing to fall off.

In 2016, researchers put sedentary men on bikes three times a week for 12 weeks. One group rode 45 minutes at a steady pace, which with the warm-up and cool-down made a 50-minute session. The other group did 3 all-out sprints of 20 seconds, with two minutes of easy pedaling between them, in a 10-minute session. Their fitness (peak oxygen uptake) rose by 19% in both groups. The sprint group did about a fifth of the exercise, and the groups were small, but it shows how much a few hard seconds can do.

The sprints really are all-out, the kind you can’t hold for long, so they’re for people who are already riding comfortably and have no heart symptoms. Steady or intervals? has gentler interval patterns to start with.

A picture from daily life

A bike is like a car with a gearbox. Low gear on a flat road, you can cruise for an hour and chat the whole way. Put it in a big gear up a hill and the engine roars within a minute. You choose how hard the ride is every few seconds, which is why the same bike can give you an easy recovery spin on Tuesday and the hardest 20 seconds of your week on Thursday.

Is an e-bike cheating?

We’d ride whichever bike gets you out the door most days, and turn the assist down as the hills get easier.

Do you need a helmet?

Yes, every time you ride on the road. In a 2017 review covering over 64,000 injured cyclists, wearing a helmet in a crash or a fall went with 51% lower odds of a head injury, 69% lower odds of a serious one and 65% lower odds of a fatal head injury. A stationary bike is the one place you can skip it.

Does cycling build strong bones?

It doesn’t do much for them. A 2012 review of 31 studies found that road cycling doesn’t seem to build bone, and that adult road cyclists who trained a lot had low bone density in places like the lower spine. The likely reason is that the bike holds your weight, so your bones don’t get the loading they get from walking, running or lifting. Mountain biking and mixing cycling with other sports looked better. If cycling is your main exercise, lifting twice a week covers what the bike misses (how to get stronger bones on strength.guide).

What we still don’t know

The commuting and sport studies followed people who chose to ride, so they show lower risk in groups and can’t promise anything to one person. The sprint trial was small and only in men. And nobody has measured whether indoor and outdoor riding differ for health at the same effort. For most people, the answer is to ride the one that fits their week.