The science behind CAROL

Science and technology combined

4 academic partnerships. Multiple peer reviewed studies. An active R&D program and data science team. CAROL takes academic research on HIIT to the next level.

Quality over quantity

CAROL utilizes science, technology, and artificial intelligence to get you the best results in the least amount of time. The dream scenario for a busy lifestyle.

Based on the scientifically proven benefits of REHIT (Reduced Exertion High Intensity Training) and rapid glycogen depletion, CAROL automatically applies the optimal resistance at the right speed at the right time for your fitness level.

As a result, the maximum intensity levels during a CAROL sprint are about three times higher than in HIIT spin classes, and it delivers greater health and fitness benefits in a fraction of the time compared to conventional exercise.

“This is real.” – Dave Asprey, Founder of Bulletproof 

“You’re spending one-fifth the amount of time on CAROL bike and you’re getting twice the results.” 

Listen now to the podcast by Dave Asprey – a biohacker, founder of Bulletproof and CEO at Upgrade Labs – to find out why he brought CAROL into Upgrade Labs and what we’ve learned from a database of over 100,000 REHIT rides.

What is REHIT?

Maximum vs. high intensity

In short, REHIT is the difference between maximum intensity training and high intensity training.

It’s based on the principal that fewer and shorter bursts at maximum intensity produce results more efficiently, using two 20 second all-out bursts designed to quickly empty the glycogen stores in your thigh muscles. Hence the name Reduced Exertion High Intensity Training, as your exertion is less than in traditional HIIT sessions.

Previously, the REHIT effect was only achievable in laboratory conditions. Now, thanks to CAROL, you can experience the benefits in your own home.

Results confirmed by research

Double the fitness gains

In 8 weeks, our REHIT workouts give double the health and fitness results compared to traditional exercise – in 20% of the time.

Real world results

In 5 weeks, participants improved their VO2max by 11% and reduced their risk of inactivity-related diseases by 20%.

Boosted Metabolism

Our 15-minute workout burns more calories than 30 minutes on a treadmill, as well as increasing post-exercise metabolism.

Rapid glycogen depletion

Survival of the fittest

CAROL’s short maximum intensity sprints trigger your body’s ‘fight or flight’ response. This evolutionary signal tells your body that it must adapt and get fitter and stronger to survive.

The sudden demand for energy forces your muscles to burn muscular glycogen – your body’s emergency energy reserve, which is sugar stored in the muscle – as fuel. Glycogen depletion improves your aerobic ability, which leads to improved fitness.

CAROL’s two 20-second sprints deplete glycogen stores by 25-30%. To achieve that level running, you’d need to keep going for 45-60 minutes. That’s why CAROL is the quickest, most straightforward way to deplete glycogen and get fitter, leaner, and healthier.

Get twice the gains of regular exercise

ACE study

CAROL’s eight-week plan can reduce your metabolic health risks by 62% and double the gains in all markers of health and fitness.

The superior gains of CAROL over traditional exercise guidelines were scientifically proven by a peer-reviewed study by the American Council on Exercise (ACE).

Use CAROL for just eight minutes 40 seconds, three times a week for eight weeks and you could enjoy the following benefits:

– Metabolic disease risk (MetS Z-Score) reduced by 62%
– Heart and lung fitness increased by 12%
– Blood pressure reduced by 5%
– Triglycerides (fat found in your blood) reduced by 10%
– Good cholesterol (HDL) increased by 6%
– Blood sugar reduced by 2%

CAROL reduces metabolic disease risk
Lose fat on and off the bike

EPOC technical report

For each minute you spend exercising on CAROL, you’ll burn double the calories than through conventional exercise. That’s because CAROL’s ‘after burn’ burns twice as many calories after your workout than during it.

Studies have shown that you’ll also benefit from improved insulin sensitivity, which helps you become metabolically flexible and access and burn your body’s fat stores.

All of which means your rider’s high will last long after you finish your workout.

CAROL burns more fat after a ride than during a ride