Discover everything about CAROL in our Ultimate CAROL Bike Resource. VIEW NOW.

The bike that gets you fittest, fastest.


Get the most effective workout in just 5 minutes with CAROL Bike - short and easy to fit into your life.


AI-personalized workouts tailored to you – simple to perform and suitable for any age and fitness level.


Scientifically proven to deliver superior health and fitness benefits in 90% less time compared to regular cardio.

Your shortest, most effective workout.

Reduced Exertion HIIT (REHIT) and AI-personalization make CAROL Bike unique.​ Just 2x20-second sprints create the most powerful training stimulus.

Your results, backed by science.

Developed in collaboration with leading exercise researchers to create the shortest, most effective workouts.

Get Fitter

Improve your fitness by 12% in just 8 weeks.

Live Younger

Improving your VO2max by 12% is like turning the clock back on your age by 10 years.

Live Healthier

Reduce your risk of type 2 diabetes by 62%—and blood pressure by 5%.

Next-level HIIT

Why Reduced Exertion HIIT (REHIT) is the most effective workout.

Maximum Metabolism

You’ll burn more calories on a 15-minute CAROL ride, than a 30-minute run.

Time to thrive

Make the most of your time with CAROL Bike's short and efficient REHIT workouts.

More on Science

Hear it from our riders.

Everett Myers
3 months

"I’ve been training for a half marathon and since adding CAROL Bike to my daily routine in the past 2 weeks, my VO2max has gone up 5% already."

Everett Myers
Fitness score
Dr Gabriela Moreno
3 months

"My CAROL Bike has been great to help me achieve greater fitness and power without the time investment but with all the fun!"

Dr Gabriela Moreno
Fitness score
Phil Cox
3 months

"It's easy to fit a quick 5-minute workout in, especially if you don't need to shower after your workout!"

Phil Cox
Fitness score
Ann Meyers
3 months

"It is a keystone health habit builder that not only makes you feel better but makes you more conscious of acting in healthier ways throughout the day."

Ann Meyers
Fitness score
Peter Bauman
3 months

"Dropping 2.6% bodyfat in ~8 weeks for someone who prioritizes a healthy lifestyle is no easy feat. I’d go so far as to label it as a gamechanger."

Peter Bauman
Fitness score
Germany Mayfield
3 months

"If you’re looking for a quick, effective biohack to improve your cardiovascular health, increase your endurance in an efficient way... this seems to be the move."

Germany Mayfield
Fitness score
Ally Sinyard
3 months

"CAROL has been a really great way for me to keep active, for me to keep moving without putting too much stress on my body."

Ally Sinyard
Fitness score

The ultimate CAROL Bike resource

Your 1-stop guide for all things CAROL, presented by our co-founder Ulrich Dempfle. Explore in-depth insights into REHIT workouts, unique CAROL features, habit-building strategies, a selection of tailored workout routines, and much more.

A simple habit, that works.

Just 2x20-second sprints, 3x a week. Scientifically-proven to be the most effective cardio workout—a moment of effort you can always master.

A Simple Habit

New riders hit an average of 3.2 rides a week, in their first 100 days.

15 Minutes a Week

CAROL Bike’s science-backed workouts. The short, smart, simple fit for your life.

AI-Personalized Ride

CAROL Bike’s AI algorithm calibrates every moment on the bike to you.

Your Progress

CAROL Bike’s Fitness Score lets you track how your fitness is improving.

Your Favorite Apps

Seamlessly connect to apps like Zwift, Kinomap, Peloton Digital and more.

Endless Entertainment

CAROL Bike integrates with entertainment apps like Netflix, Disney+, YouTube and more.

More on Habit

Good habits start here.

Order CAROL Bike now, try it for yourself—and build a habit that lasts.

100-Day Trial

Feel the benefits of CAROL Bike for yourself risk-free for 100 days. And if it’s not for you, return it and get a full refund.

Fitness Advisors

All our experts have MScs in Exercise Science—here to help you achieve your fitness goals.

Free Delivery

If you live in the mainland US, get your new CAROL Bike delivered for free in 7-14 days.

Real riders, real results.

Our riders are at the heart of everything we do. Discover the real impact of CAROL Bike straight from those reaping the benefits every day.

From our community, who know us best.

Hear how our community of scientists, fitness thought-leaders and self-optimizers make the most of every workout with CAROL Bike.

Biohacker Approved

Dave Asprey, the father of biohacking on CAROL Bike: “This is real!”

More on Community

Intelligent design, explained

CAROL Bike is the only bike fully optimized for Reduced Exertion HIIT (REHIT)— making it simple, effective, and safe. It provides the shortest, most effective workouts suitable for any age and fitness level - while offering greater versatility and choice than most other smart bikes.

Optimal design

Learn about the rationale behind our key design choices.


Fully commercial-grade exercise bike. Built for professional gyms.


Heavy-duty, powder-coated steel frame.

Instant Resistance

AI-controlled, motorized resistance applied instantly.


Silent, friction-free magnetic brake.

Power Measurement

The highest accuracy standard for professional gym equipment.


Ergonomic handlebars with 5 different grip positions.


Designed for maximum comfort.


Optimal distance between pedals of 170 mm.


Dual-sided toe cage and SPD click pedals, to maximize rider efficiency.


Forged steel 170 mm crank arms.


Silent poly-V belt with automatic belt tensioner, 1:8 gearing ratio and freewheel safety clutch


Composite flywheel with steel core and brushed aluminum outer ring.

Power Requirements

100 V to 240 V


11.5” IPS touchscreen with 2K resolution (2000 x 1200)



MediaTek® Helio G99 Octa-Core Processor



Integrated ARM Mali-G57 MC2 GPU






128 GB internal storage



Quad Speakers, Optimized with Dolby Atmos®



WiFi 6E: 802.11 a/b/g/n/ac/ax



Bluetooth 5.2



Wired ethernet via USB-C adaptor (not included)


Operating System

Android 13



A wide range of apps available via Google Playstore:​

  • Group classes with Peloton Digital​
  • Virtual rides and races with Zwift, Kinomap, Rouvy, and more​
  • Entertainment with Youtube, Netflix, Disney+ and more​
  • News with CNN, Fox, NBC and more


45.5″ x 22″

Bike Weight

120 lb

Rider Requirements

Height: 4’7″ – 6’7″

Max weight: 330 lbs

Space Requirement

45.5″ x 45.5″

CAROL membership gives you and 7 other riders the full CAROL experience.



Our AI algorithm calculates your optimal resistance, for maximum results—so every second matters.


20 Workouts

Choose from 20 scientifically-proven workouts and fitness tests. With more added as the science advances.


Multiple Riders

Home membership gives access for up to 8 riders.

Commercial membership tiers start at 24 riders.



Personalized dashboard with comprehensive performance metrics like Fitness Score; so you can accurately track how your fitness is improving.


OTA Updates

CAROL Bike automatically adds new features, functionality and performance with over-the-air software updates.



Home membership is $19.99/month (excl. sales tax).

Commercial memberships start from $49/month (excl. sales tax).


Customer support available via phone, chat, or email.


If you live in the mainland US, Canada or UK, get your new CAROL delivered for free.

100-Day Home Trial

Try CAROL at home for 100 days. And if it’s not for you, return it and get a full refund.

Paid Assembly

Get your CAROL bike delivered fully assembled for $199.

DIY Assembly

With 7-step assembly, and support via phone, chat or email on-hand—setting up CAROL is simple.

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