Get your science-backed guide for maximum fitness results—in minimal time. VIEW NOW.

Co-Founder Q&A: The science behind CAROL Bike

From how to lose weight with CAROL, to the best way of integrating strength training with their rides, CAROL’s social community sent us their questions. And who better to answer them, than CAROL CEO and co-founder, Ulrich Dempfle.
CAROL is scientifically researched and proven to improve your fitness and health. Developed in collaboration with leading exercise researchers, to create the most effective, time-efficient workout. Here’s your synopsis of the science.

Q: Why is CAROL different from other bikes?

Reduced Exertion HIIT (REHIT) and AI-personalization make CAROL Bike unique. Developed with leading exercise researchers to give you the shortest, most effective workout.


REHIT is the next-level HIIT workout that gives you double the health benefits, in just 10% of the time. CAROL Bike’s signature REHIT workout can be done in just 5 minutes. And it’s proven to be the most effective cardio.

Q: Is the 5 minute workout enough to lose weight?

With CAROL’s signature 5-minute workout you’ll burn twice as many calories minute-per-minute vs. traditional cardio, thanks to afterburn, which lasts for up to 3 hours after you ride.

Ulrich details new research by ACE (American Council on Exercise) that shows you’ll burn more calories on a 15-minute CAROL Bike ride, than a 30-minute run.

Find out more about how CAROL maximizes your metabolism.

Q: How do you suggest integrating CAROL with strength training?

Gym owners have relayed to Ulrich that their clients do strength training before their CAROL workout, and avoid leg work on CAROL days.

While there is no clear research on integrating CAROL with strength, Ulrich recommends experimenting to find your perfect regimen.

Q: Can I improve my VO2max with CAROL?

VO2max is the main measure of fitness. The higher your VO2max, the fitter and healthier you are.


Ulrich references the scientific study which proved CAROL’s signature REHIT workout can improve your VO2max by 12%, in just 8 weeks.

Q: Can I do REHIT workouts without CAROL?

REHIT was developed by scientists looking for the shortest, most effective and accessible way to exercise. Research proved that REHIT is the fastest way to get fit, but there was a catch: true REHIT was only possible in the lab.

We teamed up with the world’s leading exercise researchers to get REHIT out of the lab—into the real world. CAROL is the only way to safely and effectively recreate REHIT, thanks to AI-personalization and Instant Resistance.

Ulrich suggests the next best thing​​—all-out sprinting on a running track—but this comes with safety risks.

New Year. Fit You.

Get your free fitness guide featuring science-backed advice for becoming the fittest you—in the least time. No fads. No miracles. Just science.

Download now

Ulrich Dempfle

CAROL CEO & Co-Founder

Ulrich co-founded CAROL and partnered with the world’s leading exercise researchers to take REHIT out of the lab. 40 prototypes later, the world’s only REHIT exercise bike was launched.

Ulrich Dempfle

CAROL CEO & Co-Founder

Ulrich co-founded CAROL and partnered with the world’s leading exercise researchers to take REHIT out of the lab. 40 prototypes later, the world’s only REHIT exercise bike was launched.

Get Fitter

1 MIN READ

Live Younger

1 MIN READ

Live Healthier

1 MIN READ

Next-level HIIT

1 MIN READ

Maximum Metabolism

1 MIN READ

Time to thrive

1 MIN READ

Boost your brainpower

2 MIN READ

12 benefits of cycling

9 MIN READ

Demo: How to do REHIT on CAROL Bike

6 MIN READ

What is a REHIT workout?

6 MIN READ

Scroll to Top

8 hacks for optimal fitness

Get your free guide to improve cardio and strength based on Dave Asprey's new book.