Short
The whole ride is done in 5 minutes — warm-up, two sprints, cooldown. Three rides a week is all the habit asks of you.
5:00 rideThe 5-Minute Workout (Agen)
The 5-minute workout
Get fit in 5 minutes. Not 45.
CAROL Bike is the world’s first home REHIT bike. Two 20-second sprints, AI-personalized to you — the same health and fitness results as a 45-minute run, backed by science.
Labor Day
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Why it works
The most efficient workout there is.
Short and easy to fit into your life, smart enough to meet you exactly where you are, and proven in peer-reviewed research.
Smart
AI-personalized workouts calibrate resistance to you at every moment — simple to perform and suitable for any age and fitness level.
Any fitness levelScientific
Scientifically proven to deliver superior health and fitness benefits in 90% less time compared to regular cardio.
−90% timeInside the ride
Two 20-second sprints. That’s the workout.
Developed by leading scientists, Reduced Exertion HIIT (REHIT) creates the most powerful training stimulus from the shortest possible ride. CAROL’s AI applies exactly the right resistance at exactly the right moment — here is every second of it.
Pedal slowly for up to 2 minutes to prep for your first sprint.
AI applies Instant Resistance. You push to your limits for 20 seconds, forcing 25-30% mobilization of muscular glycogen, releasing key signaling molecules.
Pedal slowly for 3 minutes, clearing lactate and preparing for your second sprint.
Push again to your limits for 20 seconds to activate the signaling molecules released in Sprint 1. This tells your body it must get fitter, stronger.
Light pedalling for 3 minutes, so blood pressure, heart rate, and breathing go back to normal.
The rest is easy pedallingAt your limit: 0:40
The research
Your results, backed by science.
CAROL Bike is scientifically researched and proven to improve your fitness and health. Just 3x5-minute REHIT rides a week.
+12%cardio fitness (VO2max) in just 8 weeks
10 yrsa 12% VO2max gain is like turning your fitness age back a decade
−62%risk of type 2 diabetes; blood pressure down 5%
2×more calories burned on a 15-minute CAROL ride than a 30-minute run
More on the science →
Beyond REHIT, CAROL is a fully customizable indoor bike: Free Ride with control over timing, resistance and target power, plus Zwift, YouTube and Netflix integration.
The hardware
Engineered for exactly one job: your hardest 2×20 seconds.
CAROL Bike is the only bike fully optimized for REHIT — every component engineered for instant, personalized maximum intensity, at any age and fitness level.
Instant Resistance
AI-controlled motorized resistance, applied the moment your sprint starts — no dials, no guesswork.
AI-personalized
Every ride calibrates to you, from your very first calibration rides onwards.
11.5″ 2K touchscreen
Quad speakers with Dolby Atmos, WiFi 6E, Bluetooth 5.2.
Your favorite apps
Zwift, Kinomap and Peloton Digital, plus Netflix, Disney+ and YouTube on board.
Commercial-grade build
Heavy-duty steel frame, silent poly-V belt drive, friction-free magnetic brake. Built for professional gyms, sized for home.
Rider results
Hear it from our riders.
Our riders are at the heart of everything we do — and their fitness scores do the talking. Join our 35,000+ rider community.
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.
My CAROL Bike has been great to help me achieve greater fitness and power without the time investment but with all the fun!
In just 4 months, my VO2max has increased by about 12 points, and my heart rate has decreased by 10 bpm. For someone with a history of heart issues, these improvements are huge!
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.
It’s easy to fit a quick 5-minute workout in, especially if you don’t need to shower after your workout!
I get more cardiovascular benefit in 5 minutes than I used to get from 30-minute runs, and my recovery is faster too.
The community
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.
More from the community →
Biohacker ApprovedDave Asprey on why CAROL Bike is the smartest workout for self-optimizers.
“I love my CAROL Bike!”Dr. Michael Gervais on habits that compound.
A 45-minute run, in just 5Ben Greenfield on the science of REHIT.
“Most Innovative Exercise Bike”Garage Gym Reviews on why CAROL stands out from every other smart bike.
The offer
Good habits start here.
Order CAROL Bike now, try it at home for 100 days, and build a habit that lasts.
100-day trial
Feel the benefits risk-free for 100 days. Not for you? Return it for a full refund.
Delivery from $99
Delivered to your door, ready for your first calibration ride.
0% APR financing
Pay just $232.92/month at 0% APR, with Affirm.
Fitness Advisors
All our experts have MScs in Exercise Science — here to help you reach your goals.
CAROL Bike — $2,795
Save $300 with code LABORDAY at checkout
Order CAROL Bike
Before you order
Questions, answered.
How does the 100-day trial work?
Ride CAROL at home for up to 100 days. If it’s not for you, return it and get a full refund. Trial details
Do I need to be fit to start?
No. CAROL’s AI calibrates every ride to you, so REHIT is suitable for any age and fitness level — your sprints are always yours, never someone else’s numbers.
What does delivery cost?
Delivery from $99. Our team will confirm timing when you order. Delivery details
Can I finance my bike?
Yes — pay $232.92/month at 0% APR, with Affirm. Financing details
What does membership add?
Home membership is $19.99/month: unlimited riders in your household, all REHIT workouts, Fitness Score tracking, and app integrations. Membership details