CAR.O.L is a stationary bike for high-intensity interval training (HIIT) that can improve your fitness and health using artificial intelligence. What makes CAR.O.L unique is that every workout is only 40 seconds long — short enough that you won’t even sweat.
For this review, I tested CAR.O.L to find out how effectively it improves my cardiovascular performance, and to determine whether I could use the bike to complement my CrossFit training.
To see what exercising with CAR.O.L looks like in action, check out a video (below) of one of my training sessions.
Benefits of High-Intensity Interval Training
HIIT workouts have become so popular in recent years because they’re an incredibly effective way to improve your cardiovascular fitness with relatively little time investment.
Most HIIT workouts take less than 30 minutes, and some are much shorter than that. One of the most popular HIIT workouts is the 7-Minute Workout, which, as the name implies, takes only seven minutes to complete.
Another popular type of HIIT workout is called Tabata, which only takes four minutes per round.
While you can do high-intensity workouts with all different kinds of equipment or with no equipment at all — think bodyweight exercises (mountain climbers or jumping jacks) — some people prefer HIIT bike workouts to get the heart rate up and the blood flowing.
HIIT workouts on stationary bikes have the benefit that you can do them pretty much any time and from the comfort of your home — without requiring a lot of (storage) space for exercise equipment.
Intensity is what makes a HIIT session so effective, but it’s also the reason why many people don’t stick to this type of exercise routine. It’s no secret that HIIT requires a degree of willpower and mental toughness that not everyone brings to the table.
In our labs, we see insulin sensitivity improve by 25-28% and fitness by 15% within 6 weeks. The CAR.O.L stationary bike reproduces these results in the real world. The research programmed into CAR.O.L is benefiting the public, and that’s ultimately what this science is about.Dr. Niels Vollaard
That’s one of the reasons why I like CAR.O.L — each workout session lasts only 40 seconds (plus warmup, recovery and cool down).
CAR.O.L – a Stationary Bike for High Intensity Interval Training
So what is CAR.O.L?
CAR.O.L has been around for a while, but it used to be called High Octane Ride. The idea behind CAR.O.L is to take high-intensity interval training to the next level.
CAR.O.L stands for Cardiovascular Optimization Logic. It’s an AI-powered bike ergometer that the company says gets you 132% healthier in 98% less time.
That first figure is based on a METS Z-score, which is a combined score of various health markers that is often used in medical studies. In one study, CAR.O.L users’ METS Z-score was 132% better than non-users at similar fitness levels.
The “98% less time” claim is based on the reduced time it takes to complete a workout on the bike: just 40 seconds per day three days per week, as opposed to jogging for 30 minutes five times per week.
- Minimal time investment
- Scientifically-proven benefits
- ISO certified for the most accurate commercial-grade ergometer
- CAR.O.L dynamically adapts to your progress, so you never plateau
What’s more intense than HIIT, you might ask? It’s supra-maximal interval training. The goal of supra-maximal interval training is to rapidly empty the glycogen stores in your thigh muscles through two 20-second sprints at super-high intensity.
Scientists call this method reduced-exertion high-intensity interval training, or REHIT, because your perceived exertion is lower than what you experience during traditional HIIT workouts. That makes sticking with REHIT easier than with other types of exercises.
How Does the CAR.O.L AI Bike Work?
CAR.O.L uses artificial intelligence to personalize your workouts based on your physiology and ability. Think of the bike as your personal trainer, or as an exclusive indoor cycling studio that gives you a challenging cardio workout.
During the initial setup of your workout profile, the bike asks you for personal information, including your age, weight and height. Based on those biometrics, 50 years of empirical evidence around the REHIT method, and biometric data from on-board sensors, CAR.O.L constantly assesses your performance and makes continuous adjustments using 1,000 resistance settings.
In other words, every time you mount the bike, you get a personalized workout that improves your health and fitness.
What sets CAR.O.L apart from other ergometers is that the bike can replicate exact lab protocols in the real world — such as the ones used in a recently published study on the benefits of REHIT.
Dr. Niels Vollaard, a lecturer in health and exercise science at the Faculty of Health Sciences and Sport, said:
CAR.O.L is the only system that accurately replicates my research outside of the labs. This scientific exercise cannot be done on a regular bike because of the supra-maximal resistance required that also needs to be tailored to each person’s physiology.Dr. Niels Vollaard
As a result, exercising on this bike for 40 seconds a day, three times per week is more effective than going for a 30-minute run five times per week.
CAR.O.L vs. Jogging
To give you an idea of how effective cycling on CAR.O.L is compared to jogging, below are some numbers from a study that was published in February 2019, in the International Journal of Environmental Research and Public Health. The figures shown indicate how much better CAR.O.L users’ scores and improvements were when compared to those of the joggers in the study:
- Risk of developing a metabolic disease — 62% better
- Cardiovascular fitness — 78% better
- HDL cholesterol — 71% better
- Triglycerides — 78% better
- Blood pressure — 196% better
- Blood sugar — 48% better
In another study from 2011 scientists concluded that REHIT increased insulin-sensitivity in male study participants by 28%, which lowers the risk of developing Type 2 diabetes.
I’ve been following a ketogenic paleo diet for a while, and I do CrossFit four or five times per week. As a result, my bloodwork is already in the ideal range and I have no fear of developing Type 2 diabetes or other lifestyle-related diseases.
However, my measurable goal with CAR.O.L is to improve my maximum power — expressed in watts — and my octane score. The octane score is a measure of power output on the bike in relation to your heartbeat, and you can correlate that to your VO2max.
VO₂ max is the maximum rate of oxygen consumption measured during incremental exercise; that is, exercise of increasing intensity. The name is derived from three abbreviations: “V” for volume, “O₂” for oxygen, and “max” for maximum.Wikipedia
While octane score and VO2max aren’t exactly the same, they improve in a similar fashion. That means that as my octane score improves, so does my VO2max.
CAR.O.L offers the following seven workout modes you can choose from, including a free ride mode.
- Fat Burn 30
- Fat Burn 60
- Constant Power
- Continuous Ramp Up
- Free Ride
Intense is the primary program and the one I use most often. It consists of two 20-second sprints, plus a two-minute warmup, a three-minute recovery, and a three-minute cool down. So, my total time investment is eight minutes and 40 seconds for each indoor cycling workout.
CAR.O.L recommends that you work out three times per week if you want to improve your performance, health and fitness. To maintain your fitness level, you can reduce your workouts to two per week.
Given how often I do CrossFit, I don’t always get to workout three times a week on CAR.O.L. It’s not an issue of finding the time, but it’s a matter of giving my legs enough rest to recover. We’ll see how that approach impacts my octane score in the long run. For now, I think that my CrossFit training more than compensates for the missed biking sessions.
Energizer is a shortened version of Intense that consists of two 10-second sprints. I choose Energizer when I don’t feel like “killing” myself, or on days when I feel sore and I already worked out (CrossFit).
Fat Burn 30 and Fat Burn 60 are both excellent workouts if your fitness goals include burning fat or to lose weight. These two workouts consist of a two-minute warmup, 30 or 60 eight-second sprints with 12 seconds rest in between each, and a three-minute cool down.
In Constant Power mode, CAR.O.L will adjust the resistance automatically to maintain the chosen power.
Continuous Ramp Up is a testing protocol that you can use to measure your VO2max. During the test, CAR.O.L will increase the resistance by three watts every three seconds until you fatigue.
Free Ride, as the name implies, allows you to use the bike like a traditional ergometer. You can freely set the resistance and other parameters and ride for as long as you like.
CAR.O.L Hardware and Setup
CAR.O.L bikes are shipped from one of two warehouses — depending on whether you live near the east coast or the west coast — via a parcel service. I got my bike wrapped in a large cardboard box.
CAR.O.L features a stainless steel frame and a heavy flywheel. The weight is necessary for stability reasons. The good news is that assembling CAR.O.L usually takes less than 30 minutes. I put my bike together in the garage and then wheeled it into my office.
Once I had found a good spot for my bike, I made sure it was even by manipulating the four adjustment knobs on the underside of the frame.
I have hardwood flooring in my office and was afraid my sweat might damage it; then I remembered that using CAR.O.L doesn’t make you sweat. Unless, of course, you do the fat loss routines or use the bike for free riding to build up endurance.
If so, you might want to cover your floor with a protective plastic sheet — such as the ones you use underneath a rolling office chair — to protect the floor.
Software and App
When you first power up the bike, you’ll probably notice that CAR.O.L’s software is just an app running on an Android-powered tablet. That makes using and interacting with the CAR.O.L app straightforward, unless you’ve never used a smartphone or tablet before.
Before you can start your first bike ride, you have to create a rider account with CAR.O.L. You can later access this account via web browser from your computer or via smartphone app.
To ensure that nobody else can access your account, you have to protect it with a password. I usually generate and store unique and complex passwords for each account I have using an app called 1Password. Unfortunately, every time you ride on CAR.O.L, you have to enter your account username and password via the on-screen keyboard on CAR.O.L’s tablet screen.
This reason for this makes sense: the bike uses your unique rider data in its deep learning process, which is how it ensures that you always have the appropriately challenging cardio workout based on your strength and fitness levels. If other people used your account, that would undermine the program.
Still, this made it so that I couldn’t use a long and automatically-generated password for my CAR.O.L account, because I would have to look it up every time I wanted to work out on the bike.
However, instead of choosing an easy-to-guess password (such as “password” or “Michael”), I chose a password that’s hard to guess but easy to remember. To learn how I did that, check out this article about how to choose a good password.
Competing With Others
Every time you finish a workout on CAR.O.L, you can save the ride and see how you compare to every other CAR.O.L user worldwide on a weekly leaderboard.
I enjoy having this community connection and think it makes for a fun workout. Instead of just competing against my personal best performance (which can become tedious for even the most dedicated riders), it’s fun to essentially play an ongoing fitness game against other great athletes.
Riding With CAR.O.L
Riding with CAR.O.L is pretty straightforward if you follow the on-screen instructions of the workout you choose.
Before starting a workout, you can pick music or spoken instructions (this varies depending on the type of workout).
Once you’ve completed the workout, you see your score and an indication of whether you’ve improved upon your previous scores. CAR.O.L also asks you how you feel after the workout, and if you’d like to save your score or discard it.
How Much Is CAR.O.L?
For consumers, CAR.O.L costs $2,995 plus a $12 monthly subscription fee per household. Corporate users, such as gyms, pay $3,995, but they get a host of additional benefits.
If you want to give CAR.O.L a try, you can use discount code MK150 to get $150 off the purchase price.
Tips to Improve Your Score on CAR.O.L
Besides improving your conditioning by working out on CAR.O.L at least three times a week, there are a couple of tricks you can use to get the best possible score.
- Make sure the bike seat and handlebar are adjusted properly for your height.
- Use biking shoes.
- Wait until the end of the three-second countdown before going all-in.
One of the most important factors in biking efficiently is a properly-adjusted seat and handlebar. If you sit too high or too low, you won’t be able to transfer power from your legs to the bike as efficiently. So, make sure to adjust the bike according to the manual and your height.
I’ve also noticed that the pedal straps tend to loosen over time. That’s just because of the force applied when you’re peddling at full speed. For best results, I recommend getting a pair of biking shoes that you can attach firmly to each pedal.
That said, I still bike with my tennis shoes because I don’t care if I lose a few watts.
Last but not least, I recommend holding off on going all-in when the screen turns red and the three-second countdown starts. Why? Because I’ve noticed that I reach peak speed and intensity even before the 20-second workout starts.
In other words, when the actual workout starts, my performance is already declining. So, I usually wait until one second before the workout starts.
CAR.O.L.AI vs. Other HIIT Bike Workouts
So how is CAR.O.L different from other HIIT bike workouts, such as spin classes?
The primary difference between regular HIIT workouts or spin classes and CAR.O.L is the latter’s ability to rapidly empty the glycogen reserves in your thigh muscles. That’s what makes the bike so effective for increasing your aerobic capacity.
CAR.O.L can do that because of how it utilizes science, technology and artificial intelligence. In other words, CAR.O.L can personalize each workout based on your physical abilities at the time of that particular workout.
As a result, CAR.O.L can improve your cardiovascular conditioning with only 40 seconds of work. No other workout, that I know of, can do that.
CAR.O.L. vs. Spinning
Before becoming a CrossFitter, I tried various types of exercises, including spinning. From a purely physical perspective, I enjoy training on a stationary bike. Spinning was tough, but I burned a lot of calories doing it and the group setting motivated me to push even harder.
The downside of spinning is that it’s monotonous. After a while, I got bored and stopped doing it.
And another disadvantage of spinning is that it takes at least an hour — and even more if you add the time required to travel to the gym and back. If you plan on using a spin bike at home, you really have to be self-motivated and very disciplined.
Innovations like the Peloton bike have tried to offer solutions to these problems by introducing connected bikes that allow you to work out from the comfort of your home while still interacting with and competing against a community of riders.
While I think that’s a great idea, you still have to commit a significant amount of time for the workouts to be effective.
In contrast, CAR.O.L requires only a few minutes of your time. And while you can’t compete with other riders live (the rides you take with CAR.O.L are simply too short for that), you can compare yourself to others via CAR.O.L’s global leaderboard.
Who Should Use CAR.O.L?
I’d argue that CAR.O.L is a good fit for anyone who wants to improve their fitness and health without having to spend countless hours in the gym. This indoor bike is also an excellent option for those who have had a difficult time sticking to an exercise routine. Moreover, CAR.O.L is particularly useful for those who have a demanding job or family life that leaves little time to work out.
CAR.O.L is also great for serious athletes who seek ways to complement their primary workout routine and improve their cardiovascular strength and capacity.
I do CrossFit multiple times each week, but I also enjoy using CAR.O.L on the days when I don’t have time to go to the gym. Additionally, I use CAR.O.L to improve my octane score and VO2max, which helps me during those WODs that focus on metabolic conditioning (metcon).
Paired with low-heart-rate workouts, I’ve noticed that my workout performance and endurance during metcon exercises has dramatically improved over the past few weeks.
CAR.O.L’s screen is an Acer tablet running the Android operating system. That means CAR.O.L’s software is simply an Android app that communicates with the bike’s sensors.
Considering that we are an all-Apple household, CAR.O.L is the first (and probably last) Android device in our home.
Since I don’t necessarily trust Android (or any of the bloatware that might run on it), I’ll probably quarantine the bike in its own VLAN so that it doesn’t have direct access to any of the other devices that are connected to my home network.
Frequently Asked Questions
If you stumbled across this article, chances are that you already know what HIIT means. For those of you who don’t, let me quote Wikipedia:
“High-intensity interval training (HIIT), also called high-intensity intermittent exercise (HIIE) or sprint interval training (SIT), is a form of interval training, a cardiovascular exercise strategy alternating short periods of intense anaerobic exercise with less intense recovery periods, until too exhausted to continue.”
One of the most famous HIIT workouts you may have heard about is Tabata. During Tabata you perform an exercise, such as pushups, at high intensity for 20 seconds before resting for 10 seconds. Then you repeat that cycle for eight rounds.
If you did the math right, you’ll realize that one round of Tabata takes only four minutes to complete. If you repeated that exercise at the proper intensity — for a total of eight minutes — you should be on the ground trying to catch your breath.
While high-intensity interval training is relatively new, there are several scientific studies that show the benefits of such cardiovascular exercise strategies, including improved athletic capacity and condition, improved glucose metabolism, lower insulin resistance, a reduction of fat and weight loss, improved brain power and cognitive function, a decreased risk of developing cardiovascular disease, and an increased VO2 max (maximal aerobic capacity).
From a practical perspective, HIIT sessions often have a duration of 30 minutes or less. That makes them attractive alternatives for busy people who don’t have time to go for a long run or spend two hours in the gym.
The combination of short duration and high effectiveness is why the 7-Minute Workout became so popular a few years ago. In fact, before I started CrossFit, I included P90X and the 7-Minute Workout as part of my fitness routine.
The downside of HIIT is what makes it so effective — its intensity. It usually requires a high level of motivation to push through those high-intensity intervals, and many people don’t have the willpower for it.
As a result, some people give up early and abandon HIIT, or they perform the exercises with less intensity, which significantly reduces the workout’s effectiveness.
That’s why I was so excited when I stumbled across CAR.O.L — a new bike HIIT platform — which effectively reduces the workout to two 20-second bursts. Everyone can push it for 20 seconds, even if you don’t have the strongest willpower when it comes fitness.
There are numerous types of HIIT regimens that differ mostly in length, type of exercise and intensity. However, based on a study from 2016, there wasn’t a significant difference in outcome and benefits between them.
Here are a few popular HIIT regimens that you might have heard about — each of them carry the name of their respective inventor: Peter Coe regimen, Tabata regimen, Gibala regimen, Zuniga regimen, and Vollaard regimen.
I won’t go into the details of these HIIT workouts, but if you’d like to learn more, just click on the respective links above.
I’m not the most gifted handyman, but it took me less than 30 minutes to assemble my CAROL AI Bike. All the instructions are pretty straightforward and easy the follow, with one exception: I didn’t know how to attach the straps to the pedals, because that step wasn’t properly documented and I had never used them before.
The photo below shows how I have them now.
Yes you can! The CAROL AI Bike uses standard bike parts. As a result, you can use your own seat and pedals, if you prefer (and if doing so makes the workout more comfortable).
CAR.O.L has a few showrooms in the U.S. and across Europe where you can try out the bike. I tried the bike at the last Paleo f(x) show in Austin, Texas, and got hooked on the platform.
If you’re a gym or business owner, you might also consider offering CAR.O.L to your customers and employees. CAR.O.L is particularly well-suited for office environments because employees can complete a workout over lunch in business attire without breaking a sweat.
You absolutely can! CAR.O.L has two workout routines specifically designed for fat loss. In free ride mode, CAR.O.L even tracks calories burned.
However, if you eat well and exercise regularly, there’s no need to count calories.
From a health and fitness perspective, a recumbent exercise bike is basically the same as a traditional bike ergometer. Based on everything I know, I’d say CAR.O.L outperforms recumbent exercise bikes (which focus only on resistance training, and not on intensity training) on every level.
It’s the principle of quality over quantity. CAR.O.L’s workouts do essentially the same thing as a longer workout; they just get your body to the outcomes you’re looking for more efficiently. What you have to realize is that normally, you’re not actually in your target fitness zone over the duration of your workout. If you run for 30 minutes, only a portion of that is truly “productive” from an exercise science standpoint.
More specifically, CAR.O.L uses technology and deep learning to give you just the right levels of resistance at just the right moments based on your particular fitness level, which quickly burns through your glycogen stores (especially in your thighs). This helps you burn fat (spurring weight loss) and build muscle.
While CAR.O.L is a cloud-based, networked exercise system and any offline mode will always come with some compromises, the company is working on such a feature.
Some of the functionality you might lose in offline mode include personalized resistance adjustments, statistics and settings.
CAR.O.L Review – Closing Words
I used to be a professional sprinter and leveraged HIIT workouts to stay fit after I ended my career and before starting CrossFit.
One of the reasons why I like CrossFit so much is because it offers a variety of exercises that help me improve my physical fitness, including weight training, circuit training, aerobic exercises and more.
That’s why I wouldn’t consider CAR.O.L — or any other piece of cardio equipment — a replacement for strength training of CrossFit. However, I think CAR.O.L perfectly complements my current exercise regimen. More than that, CAR.O.L helps me to be a better CrossFit athlete by improving my VO2max and aerobic capacity.
But you don’t have to be a CrossFitter to benefit from CAR.O.L. In fact, regardless of what sport you do, you can significantly and easily improve your performance with this HIIT bike. If you don’t exercise at all yet, then what are you waiting for? Give CAR.O.L a try and get on your path towards better health!
Have you tried CAR.O.L or other HIIT workouts before? If so, let me know about your experience, and whether it helped you achieve your fitness goals, by leaving a comment below!
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