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Why CAROL is the only bike suitable for REHIT

CAROL Bike uniquely caters to REHIT workouts, blending cutting-edge technology with optimal resistance control, and AI-personalization—establishing it as the only suitable option for executing this innovative, time-efficient exercise method.

The evolution of efficient workouts

In today’s fast-paced world, the quest for efficient and effective exercise methods has never been more crucial. This search has led to the development of Reduced Exertion HIIT (REHIT), a form of exercise that maximizes results while minimizing time input. At the forefront of this innovative approach is the CAROL exercise bike, uniquely engineered to maximize the benefits of REHIT workouts. But what makes it stand apart from conventional stationary bikes as the only viable option for executing REHIT workouts? This comprehensive article delves into the unique features of CAROL and the challenges of traditional stationary bikes in conducting REHIT.

Understanding REHIT and CAROL's edge

REHIT is not just another fitness fad. It is a scientifically validated method that revolutionizes how we approach high-intensity workouts, optimizing them for both efficiency and effectiveness. The core of a REHIT workout on a CAROL AI bike involves 2×20-second sprints, which are proven to deliver significant health benefits, akin to those of longer, traditional exercise routines. In fact, you can achieve superior health and fitness benefits to traditional cardio workouts on a CAROL Bike—in 90% less time. But achieving the optimal REHIT effect requires more than just any stationary bike.


You can explore the unique features of CAROL Bike in more detail in this article.

Challenges of conventional bikes for REHIT

Ulrich attempts REHIT on a well-designed, high-quality and commercial grade, conventional stationary bike—similar to those used in group classes in a gym.

Attempting a REHIT workout on a standard exercise bike reveals several limitations:


Manual resistance adjustment


Conventional bikes require manual resistance adjustments, often through levers or knobs. Even if a rider knew what their optimal resistance was, it would not be easy to dial in correctly with a lever or a knob. This method lacks the precision necessary for the immediate, high-intensity changes crucial in REHIT workouts. 


Fixed transmission limitations


Standard bikes with a fixed transmission between the cranks and flywheel restrict rapid changes in intensity and pose a risk of injury due to the kinetic energy stored in the flywheel.


Inability to accommodate dynamic power changes


Regular bikes with computer-controlled brakes and programmed workouts can’t adapt to the variable power demands of a REHIT sprint. They are designed for steady target power, not the fluctuating intensity of REHIT, which these bikes can’t replicate or adjust to in real-time.

Why CAROL excels for REHIT

Discover the unique features that make CAROL Bike suitable for REHIT.

In contrast to regular stationary bikes, CAROL Bike offers several key advantages and is the only piece of exercise equipment fully optimized to perform REHIT effectively and safely:


Instant, automated resistance application


CAROL’s cutting-edge computer-controlled brake system instantly applies the precise resistance needed, right at the moment it’s required, and in a fraction of a second—ensuring maximum efficiency and safety for effective REHIT workouts. This instant shift from low to high resistance is not feasible on a conventional stationary bike, as demonstrated by our co-founder in the above video clip.


Personalized resistance adjustments


CAROL’s AI algorithm fine-tunes resistance based on your personalized ride history—as you get fitter and stronger, the resistance will adapt to ensure you are always working at your maximum intensity. Providing a fully customized and effective workout experience. 


Robust hardware for intense workouts


The risks associated with traditional stationary bikes, such as the danger of losing rhythm, are eliminated with CAROL. Additionally, with most other bikes, even if they are high-quality, you will feel a lot of flex in the frame whereas you won’t with CAROL. This is thanks to its robust, heavy-duty frame that is built to withstand the intense forces of REHIT sprints—making REHIT rides not only more effective but also safer.

Can you do REHIT without CAROL Bike?

Watch our co-founder discuss the limitations and safety concerns of using other exercise methods for REHIT.

While there are alternatives to performing high-intensity workouts, none replicate the specific REHIT experience safely or effectively:


When considering alternative methods to replicate REHIT workouts, several options present significant limitations. Treadmills, steppers, ellipticals, and rowing machines, for instance, pose a high safety risk due to the challenges of performing explosive, all-out sprints safely on such equipment. The movement dynamics of a rowing machine, particularly its jerky nature, are also not conducive to the smooth execution of REHIT. The idea of sprinting up and down stairs was tested but quickly dismissed after an incident resulted in a sprained ankle, underlining the potential for injury. 


Regular exercise bikes also fall short, as outlined above, lacking the capability to adjust quickly and accurately to the optimal resistance levels needed for effective REHIT workouts, thereby making them far from ideal for this specific type of high-intensity training.


Bodyweight exercises like burpees fail to reach the necessary intensity levels within the brief timeframe required for REHIT. For example, with 20 seconds of burpees, you can’t get your heart rate anywhere near the level of where it goes on a CAROL Bike.


There are 2 options you might consider, however they do not replicate the specific REHIT experience as effectively as CAROL:


Air bikes


Though they offer rapid resistance changes, air bikes lack the personalization and precision of CAROL Bike, and often fall short in terms of tracking and quiet operation.

Sprint tracks


Outdoor sprints offer no cost but come with safety concerns, potential joint strain, and lack the precise measurement and tracking capabilities of CAROL Bike.

CAROL: The optimal REHIT bike

In conclusion, while other methods and bikes can offer high-intensity workouts, none can deliver the precise, personalized, and scientifically grounded experience of REHIT like the CAROL exercise bike. Its blend of technology, AI-personalization, and robust design makes it uniquely suitable for maximizing the benefits of REHIT workouts.


For those intrigued by the science and innovation behind CAROL, delve deeper into its capabilities and the principles of REHIT by exploring our comprehensive guide and watching informative video clips featuring our co-founder’s insights. Discover why CAROL is more than just an exercise bike—it’s the key to unlocking the most efficient and effective workouts possible.

Got a question? Let's book a call.

All our experts have MSCs in Exercise Science, and they’re here to answer your questions. Whether it’s about the science behind CAROL Bike, or general fitness advice, whatever’s on your mind—we’re here for you.

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