The shortest,
most effective
cardio
AI-powered workouts proven to give you the benefits of a 45-minute run in as little as 5 minutes.
Shorter, smarter workouts
Effective cardio workouts from just 15 minutes a week
A 5-minute workout 3 times a week. This is cardio without the dread, thanks to the science of reduced exertion high-intensity interval training (REHIT).
Get in the best shape of your life in 8 weeks
In 8 weeks you’ll increase your cardiorespiratory fitness by 12%, reduce your risk of type 2 diabetes by 62% and give yourself an added 2 years of healthy lifespan.
Personalized workouts push you to your limits
CAROL’s AI calibrates and optimizes each ride for you. It’s like having a personal trainer right in your bike — CAROL knows exactly how hard to push you to get results.
Get double the results
Studies have proven that doing three REHIT workouts a week will give you double the health and fitness gains vs. five 30-minute moderate intensity workouts per week.
Get fitter
In 8 weeks, you’ll increase your cardiorespiratory fitness by 12% (measured by VO2max) — and see the difference in your endurance, especially when you get to the top of the stairs
Stay healthy
You’ll reduce your risk of type 2 diabetes by 62%, lower your blood pressure, triglycerides and blood sugar, and add 2 years of healthy life expectancy to your lifespan
Boost your metabolism
REHIT triggers the afterburn effect, burning twice as many calories, minute-per-minute vs. traditional exercise
Book a FREE fitness consultation
Talk with our fitness experts with Masters in Exercise Science to learn more about the science of REHIT and how CAROL can benefit you. Whatever your fitness level or knowledge, CAROL bike can help you reach your fitness goals.
BOOK NOWJoin 17,000+ riders
How it works
1. Science-backed REHIT
Our scientifically proven REHIT workout can be done in as little as 5 minutes. That’s 2x 20-second maximum intensity sprints plus warm up, recovery and cooldown.
2. AI-powered personalization
Your ride is completely controlled and personalized for you by CAROL’s AI. The resistance is set and automated for you — so you can hit your maximum intensity and get faster results.
3. Smart fitness tracking
CAROL’s smart metrics will show you both your actual and target heart rate, cadence and power. After every ride, you’ll get a report of your performance and improvements across the board.
Get started with CAROL today
0% financing options available
Pay over 12 months with 0% financing available through Klarna or Affirm financing.
(US and UK only)
Free delivery and 30-day trial
Experience the benefits of CAROL for yourself, risk-free with free delivery.
(US and UK only)
3-month free membership
Benefit from AI-optimized resistance, detailed performance metrics, and new workouts and features with CAROL membership.
Not another exercise bike
No instructor-led classes
CAROL’s REHIT workout can be done in just 5 minutes. Hop on, get a great cardio workout, and then get on with your day!
A fully automated workout
CAROL’s AI guides and controls your workout. You don’t need to push any buttons or worry about finding the right resistance — every ride is calibrated to maximize your performance and results.
Scientifically-validated results
CAROL’s REHIT workouts were developed by scientists — they’ve been tested and proven to provide the most effective, efficient cardio workout available, both in the lab and in the real world.
Backed by science
CAROL’s revolutionary workout is based in the science of REHIT, Reduced Exertion High-intensity Interval Training.
This is HIIT, taken to the next level. Developed by scientists looking for the most effective, efficient workout possible.
It turns out that two 20-second, maximum intensity sprints are all you need for a great cardio workout. Those two sprints are like a switch — triggering a release of glycogen from your muscles that tells your body it needs to get fitter, now.
Trusted by health and fitness pros
“This is real. You’re spending 1/5th the amount of time on CAROL bike and you’re getting twice the results.”
Dave Asprey
Founder, Bulletproof and Upgrade Labs
— Hear why Dave loves CAROL on Bulletproof Radio
“In our labs, we see insulin sensitivity improve by 25-28% and fitness by 15% within 6 weeks. The CAROL bike reproduces these results in the real world.”
Dr. Niels Vollaard, PhD
REHIT Researcher, University of Stirling
“REHIT workouts generate a meaningful EPOC (excess post-exercise oxygen consumption, known as afterburn), that can have an important impact on the overweight and obesity epidemic.”
Lance Dalleck, PhD
Professor of Exercise and Sport Science, Western State Colorado University