the CAROL Bike 2 Review and $/£250 Discount Code vs Peloton Comparison

[caption id="attachment_77268" align="aligncenter" width="615"] carol bike 2 review & discount[/caption] CAROL Bike 2 Review and Discount Code A close friend urged me to try her CAROL Bike 2.0 and then review it afterwards. I became intrigued by CAROL's claims of boosting fitness through very short but intense workouts. Two 20-second intense efforts, three times a week. Really? Yes, really. For those of you who are pressed for time, let's start off with a summary review of the CAROL Bike. Updated: 2 December 2022 If you've just come for the Carol Bike discount code then use TFK at CarolBike.com for a $/£250 promo discount! which will be the same or better than the current offer carolbike.com. Thank you. Let's go... TL;DR - CAROL Bike 2.0 is a good product with good, science-based workouts. If used correctly, the short workouts will make you fitter in a time-efficient manner. Carol Bike 2.0 is a significantly better-built bike than a Peloton Bike and at a lower price level. More: carolbike.com [wp-review id="67114"] [caption id="attachment_77267" align="aligncenter" width="496"] Trustpilot Customer Review Ratings of Carol Bike 2[/caption] Two workouts per week will maintain your fitness and 3 will improve it. Simple. Is Carol Bike 2 Worth It? Carol Bike 2.0 is worth it for a certain kind of person. If you are time-crunched and want quick wins in a more private home setting, then Carol Bike is a good choice. A Peloton Bike & Subscription is more expensive and the Peloton bike is certainly of inferior quality to Carol Bike. Carol Bike 2 is also worth it if you want to share multiple logins to the fitness service with flatmates or family for one fixed price. CAROL Bike - In Action. Review Videos Here's a quick video of the first part of one of the short 20-second workouts. I've abbreviated the previous 3-minutes of pedalling really, really slowly before the 20 seconds of hard effort kicks in. My friend's best sprint peaked at just under 1000w and beat me. The BBC has a few programs where the CAROL bike is used including one by their science presenter Dr Michael Moseley. Here is Lara Lewington from BBC Click and her thoughts on the CAROL Bike. CAROL Bike 2 Review - Does it work? Theory: A small number of intense efforts deplete muscle glycogen stores to stimulate a response that results in improved fitness (VO2max). Fact: As a muscle rapidly depletes 25% of its glycogen reserves, it produces AMP-activated protein kinase (AMPk) and PPARG coactivator-1 alpha (PGC-1a) which creates new mitochondria. Repeated bursts of intense effort are a way that elite athletes and casual fitness users regularly employ to improve aerobic capacity and heart function. One way of looking at this is to understand that such High-Intensity Interval Training (HIIT) can allow your heart to operate at a higher level for longer simply because the rest period allows your muscles to partially recover. Maybe you could manage a continuously high effort over 5 minutes but you probably could sustain 6 identically intense efforts of one minute each with a short rest in between. This type of training absolutely does work and no one disputes the benefits of HIIT as part of a rounded training program. However, CAROL Bikes are employing this and other research to a unique concept they call reduced exertion High-intensity Interval Training (reHIT). A typical reHIT workout could total 9 minutes and comprise only two twenty-second maximal efforts. Yep, you read that correctly. CAROL claims such efforts deplete the glycogen (energy) stored in your muscles to stimulate a positive response in your body's fitness. For fit athletes, I can't see this kind of exercise offering much improvement. However, as a means of quickly boosting someone's fitness when starting out, then there could be something in it. I'll comment on some of the supporting science further on. I would add that CAROL's workouts could be replicated elsewhere, for example, as running workouts on a treadmill. One thing to bear in mind, however, is that intense sprinting is likely to quickly injure you, especially when starting on your fitness journey. Sure you could instead get knee or other injuries when cycling but my feeling is that indoor cycling, on the whole, is safer, poses less risk of injury and is still one of the more effective exercise types as it targets large muscle groups. Who is it for? CAROL Bike buyers tend to be 40+ years old, and looking to get fit quickly by committing the minimum amount of time. If you are a regular cyclist then CAROL is more designed for your family members and perhaps also for you to use to supplement your other, road-based training. I was surprised that most of my household was keen to use CAROL. The time-effective workouts were very important to them and the ease of use made it preferable to using a 'real' bike attached to a bike trainer and definitely preferable to the cold and dangers of cycling outside. Indeed, I could easily use CAROL a couple of times a week either when I didn't fancy my planned workout or by combining an intense CAROL workout with an easy run. However, it's a media loaner, I'm returning it and I already have a bike 'turbo' trainer! Science & Technology There's a surprising amount of science on reHIT that I didn't know about. Here's a quick overview of the science and then some thoughts on that and the CAROL technology. Research Papers & Professional Quotes - Carol Bike Review This research (Source) suggests that generic high-intensity interval training (HIIT) improves aerobic capacity and cardiac function ie you are more able to burn fat throughout the day and your heart works better. Other research (Source) indicates that Carol's reHIT may also lead to improvements in cardiorespiratory fitness, blood pressure and other benefits, not forgetting the time saved from super short workouts. Interval training is the closest thing we have to an exercise pill. A tiny bit of sprint training has the same effect on the human body as a whole lot of endurance training. Martin Gibala, PhD (Author, The One-Minute Workout) CAROL is the only bike that accurately replicates reHIT outside of the labs. This scientific exercise cannot be done on a regular bike because it requires supra-maximal resistance tailored to each person’s physiology. Dr. Niels Vollaard, PhD (Exercise Physiology Researcher, University of Stirling) reHIT workouts generate a meaningful EPOC (excess post-exercise oxygen consumption, known as afterburn), that can have an important impact on the overweight and obesity epidemic. Lance Dalleck, PhD (Professor of Exercise and Sport Science, Western State Colorado University) Some of the headline findings from the research show that these results are possible by using Carol's workout protocols for less than half an hour IN TOTAL a week (yep). 12% higher cardiorespiratory fitness (VO2max) 6% higher HDL (good) cholesterol 10% lower triglycerides 5% lower blood pressure 2% lower blood sugar And here are some of the studies if you have time to go through them. MDPI Medical Journal: the positive outcomes of 8 weeks of reHIT International Journal of Research in Exercise Physiology: Estimates the calorie expenditure from EPOC from short & intense CAROL workouts National Library of Medicine: 3 CAROL workouts per week for 15 weeks boosted insulin resistance and reduced fat in young women's legs & trunk Researchgate.net: an 8-week study showed CAROL reHIT was more impactful on VO2max than medium-intensity workouts MDPI: 12% Improvement in VO2max (in untrained individuals) HIIT Science In a nutshell: HIIT increases mitochondrial activity, whereas an increased training volume increases mitochondrial mass. Citation Adaptations to Endurance & Strength Training Scandinavian Journal of Science In Sport My thoughts on the scientific claims Elsewhere, CAROL claims that its workouts are glycogen-depleting. This is confusing as two 20-second maximal efforts will probably deplete muscle ATP+phosphagen stores but only lower muscle glycogen by between 25% & 50%. If CAROL instead claimed it optimised the stimulation to the anaerobic glycolysis system or boosted VO2max and increased long-term EPOC then I'd find less to disagree with. Either way, it does something highly positive for your fitness! and I'm open to accepting that short intense efforts for untrained individuals are much more positively impactful than might intuitively seem to be the case. HIIT intervals like TABATA repeat many sets of 20 seconds of intensity+10 seconds of rest, and these will progressively reduce muscle glycogen, probably totally reducing it before relying on liver-based glycogen stores. If muscle glycogen depletion is the goal then TABATA-like intervals obviously deliver more cumulative depletion than 2x 20-second reHIT intervals, as each rest period allows muscle glycogen levels to partly recover. TABATA workouts are extremely tiring and relatively untrained individuals may need up to 4 days to properly recover from them. Check out these charts to see what I mean about the energy sources used as you exercise: [gallery type="rectangular" columns="2" size="medium" ids="67666,67291"] My thoughts on the Carol Technology Turning to technology, CAROL claims that they are powered by Artificial Intelligence. I know that some readers of my blog are (or were) literally nuclear physicists who use Machine Learning (ML) and so I'm not going to support Carol's claim that it uses AI or ML. Let's say Carol uses adaptive power algorithms to personalise the bike's resistance levels - that's a more correct statement but it doesn't sound quite as good! The Carol display is an Android tablet that runs the Carol app. It's a straightforward & robust app that is able to connect to HR chest straps and Bluetooth headphones. It does the job. CAROL Bike 2 Review - Setup and General Usage The CAROL Bike came already assembled for this review and all I had to do was plug in the power, thread the foot straps around the pedal and then attach the optional smartphone holder. If you had to assemble it yourself for whatever reason I guess it would take 30 minutes. CAROL can be levelled out on uneven flooring using the four knobs under the bike's feet. Talking of which, you can put CAROL anywhere if you only plan to do short workouts. You will literally not sweat on your carpet! CAROL bike is heavy (59kg/130lbs) but that should not be a problem for the floors of any normal house. If you live in a flat, CAROL will not cause vibration to the floor below unless you are a heavier athlete generating much higher levels of power than me ( >1000w) You'll then need to adjust the bike for comfort. The saddle can go up, down forwards or backwards and the handlebars can similarly be adjusted up and down. As a rule of thumb for setting the seat height, you should adjust it so that you can just pedal backwards using your heel and without your hips rocking from side to side. Next, move the saddle forwards/backwards and ensure you have a slight bend at your elbows when pedalling. If anything hurts, the typical advice is to 'put the saddle down a bit'. That's the very simple version of how to set up a bike! The display is an Android tablet and it is straightforward to set up the CAROL app on it. You can add 8 family members and friends and 'logging in' is a single press of one button. Super Easy! You can add passwords if you prefer. It takes 5 short rides to unlock the full suite of CAROL workouts. These 5 short rides are CAROL's signature rides that involve two 20-second maximal sprints and each last less than 10 minutes in total! After that, there is a wider variety of workouts to try, ranging from even shorter sprints to longer endurance rides and there's also a free ride/just pedal mode. You won't sweat in those unlocking rides. However, when performing other CAROL rides you might want to put a towel on the floor or some other kind of protection The more you use CAROL, the more it is able to give you feedback on your performances on the (optional) league tables and on your progress. More advanced cyclists might want to use specialist clip-in cycling shoes but there really is no need to do that and I mostly used trainers. CAROL comes with Shimano's SPD-compatible pedals and you can swap over to your own pedals too if you have them. The touchscreen tablet is responsive and works well and the menus, charts and leaderboards all make intuitive sense to me. [gallery size="medium" columns="2" link="file" ids="77273,77272"] CAROL Bike - Riding & Workouts CAROL offers 7 workout modes, including a free ride mode. You can use the free ride mode with, for example, Apple Fitness+ Workouts which does NOT control the resistance on ANY bikes. Intense - The signature 8-minute session comprising two 20-second sprints Energizer - An even shorter workout of two 10-second sprints. For me, about 8 seconds is a truly maximal effort. Fat Burn 30 - Thirty 8-second sprints with 12-second recovery Fat Burn 60 - Sixty 8-second sprints with 12-second recovery Constant Power - Resistance is continually adjusted to match your target power. Continuous Ramp Up - These can estimate your VO2max as the resistance is progressively made more difficult until you can't continue Free Ride - Great for longer or shorter endurance rides Two workouts per week will maintain your fitness and 3 will improve it. Simple Before you start your chosen workout, you can select music, on-screen instructions and even use Bluetooth earbuds. Whichever workout you choose, you get to enjoy it on a comfortable and adjustable bike. When the bike automatically changes resistance levels, the 14kg flywheel makes the transition in effort feel smooth. I compare that to my Wahoo Kickr turbo trainer which I find can apply resistance changes too harshly making it harder to quickly adapt to an increased resistance level. These reHIT workouts are going from very low resistance to maximum resistance in a few short seconds. [caption id="attachment_67506" align="aligncenter" width="300"] Click to see breathing in action on YouTube[/caption] There are clear instructions on the tablet screen that show what you've achieved and countdowns to the next effort. 'Chilled' messages periodically tell you to ease up in the recoveries...a welcome change from being badgered into trying harder in the hard bits! The top of the screen sometimes also shows guided breathing for the recovery periods. This is surprisingly difficult but worth persevering with as guided breathing can improve your HRV (see HRV4Biofeedback for more on breathing and HRV). Afterwards, your workout is scored so that you can check on your progress and there is a nice dashboard giving some more insights for those who want them. [caption id="attachment_67507" align="aligncenter" width="227"] comparing to power meter data on the watch![/caption] CAROL Bike 2 Review - Stats & Leaderboard You can compete against the performances of other athletes and you can see your position on either the global leaderboard or local leaderboard to see what performance levels are possible. However, there are a lot of CAROL bikes out there and some pretty awesome athletes are using them so don't expect to top the tables any time soon! Of more interest will be the stats that show you your workout compliance ie how well you completed the workout compared to the plan. Then you will want to see how your results and physiological parameters trend over time. CAROL Bike gives you super-simple stats like the number of workouts per week and then more complex ones like the Octane Score which shows how much power your body can produce for each heartbeat. The longer-term goal with CAROL is to progressively increase your Octane score. CAROL Bike - Accuracy There is no way to access the data with third-party software and there is no way to calibrate the inbuilt power meter. The resistance feels consistent with what power I produced but the power was understated by between 8-10% compared to an Assioma pedal-based power meter that I used for comparison (see image above). That pair of Assioma pedals are accurate to +/-1%. Improvements to your own stats over time feel correct in the sense that this bike's power/resistance 'felt' consistent - as evidenced by my Peak Power in successive workouts over several days remaining the same +/-2watts. CAROL Bike 2 Specifications Here are the CAROL Bike specs. It is a heavy bike with a medium-weight flywheel that's quiet and comfortable to use. Drive Mechanism Silent Poly-V belt drive, freewheel clutch Power Mains (110-240V) Saddle Ergonomically sculptured & comfortable Pedals Standard fit, dual-sided toe cage & SPD click pedals Crank length 165mm, as a rule of thumb this is suitable for people of around average height and shorter. Q-Factor TBC. Frame Commercial-grade stainless steel Connectivity Bluetooth (headphones & HR monitors) WiFi for Internet Max User Weight 130kg/286.6lbs Product Weight 59kg/130lbs (assembled) Area Footprint Length 116cm/45½”, width 56cm/22” Flywheel 14kg, depending on the gearing, a heavier flywheel is harder to get spinning Gearing 1:4.9 CAROL Bike 2 vs. Spinning, HIIT Bike Workout, Spin Classes The main difference is that CAROL reHIT workouts are much shorter. Their effectiveness over extremely short durations comes from extremely high or very high exertion levels. The positive effects of HIIT and reHIT are similar...it's just that the latter are shorter. The short-duration workouts also nicely deal with the boredom factor. You haven't got time to get bored... your workout is over and you move quickly onto the next thing in your hectic, daily schedule. Peloton, Zwift and others try to counter the boredom factor by increasing the social factors around the workout...but their workouts take more time to complete. In many spin classes, you have to set the resistance level yourself. With CAROL, the resistance level is automatic and personalised to your ability level. More than that, the resistance levels are changed as you start the intense effort. That is more difficult to get right on a basic spin bike. Calories Burned & Weight Loss Ignoring water retention, the only way to naturally lose weight is with a calorie deficit. Burn more calories than you consume, it really is that simple and CAROL can definitely help make that process easier. The number of calories burned during a short CAROL reHIT workout will be small. There is, however, a long-term increase in calories burned after the workout (see EPOC) as your body adapts to the stress of the workout. Carol works quickly to make you stronger and more able to exercise with a lesser risk of injury to keep you able to train. CAROL would say that after several months you should start to introduce a longer HIIT workout and a once-weekly endurance workout into your regime. You can do all of those on your CAROL Bike and 3 or more workouts a week will get you fitter and improve how you burn fat as an energy source Must Read: Lumen - A breathalyser that tells you if you are burning fat or carbs. Lumen will prove to you that CAROL works. [caption id="attachment_67643" align="aligncenter" width="300"] Your Peloton subscription pays for nice shops, their branding and a cheaper-grade bike.[/caption] A Comparison of CAROL Bike, Peloton and the NordicTrack s22i When compared, CAROL Bike and Peloton are similarly priced. Peloton is better for longer rides and socialising in group classes whereas the CAROL Bike is a better-made piece of kit. CAROL Bikes claim it is the only one that is specifically designed to support reHIT protocols with the software automatically adapting resistance levels as your performances improve. The Peloton+ bike has a larger screen to support the interactivity on longer rides whereas CAROL has a built-in heart rate monitor to give the Octane scores as well as coming with 'proper' SPD cleats for bike shoes so that you can eke out a little extra performance! Furthermore, CAROL has built-in safety features that stop the workout if abnormally high heart rates are detected. This safety feature is not offered by either Peloton or NordicTrack. Comparison CAROL Bike Peloton Bike+ NordicTrack s22i EN ISO 20957 certification Class SA: professional and commercial use Class H: domestic use Class H: domestic use Hardware Silent belt drive Yes (it's quiet) Yes Yes Frictionless magnetic brake Yes Yes Yes Motorised brake system Yes Yes Yes Freewheel weight 14Kg 17Kg 14.5Kg Freewheel safety clutch Yes No No Cycling shoes Yes (Optional) No No Hand heart rate monitor Yes (Optional chest strap) No No Cadence sensor Yes Touchscreen monitor Yes Yes Yes Bottle Holder Optional Yes Yes Software Computer-controlled brakes Yes Yes Yes Continuously personalized and optimized workouts Yes No No Precise fitness tracking Yes No No Safety algorithms Yes No No Workouts Live streaming fitness classes Yes, Claimed* Yes Yes Live streaming gaming/racing content Planned No No Moderate-intensity continuous training Yes Yes Yes Reduced exertion high-intensity training (reHIT) Yes No No Cost $2,395.00 plus $12/month (£2195, CA$2949) $2,495.00 plus $12.99/month $1,499.00 plus $39/month Interest-free financing Yes Yes Yes Shipping Included (UK, USA) Included Included *CAROL Bikes state this requires a subscription to a third-party app eg Peloton Digital, Apple Fitness+, Zwift [caption id="attachment_77269" align="aligncenter" width="300"] carol bike 2 vs peloton comparison[/caption] The Problems With the CAROL Bike Approach Don't get me wrong, CAROL is a great bike for those of you starting out on your fitness journey and who want a quick boost to your fitness in a time-efficient way. That said, the two 20-second workouts are not a long-term magical panacea. They are, however, a great way for quick wins over the course of several months, indeed CAROL quotes science that supports that. In the longer term, you will need to perform a combination of exercises to improve fitness parameters beyond VO2max (like CAROL's Octane Score). Although VO2max certainly is a good parameter to improve. Carol Bike supports this. Recommended: What seems to work best for many is a polarised fitness regime. ie short and intense workouts coupled with less frequent long/easy workouts. That approach is conceptually easy to understand and CAROL supports both those types of workouts. Add some other sort of strength training or Pilates and all will be good. Another way to explain it: more intense workouts build fitness and strength and longer workouts burn calories and train your body to effectively burn calories from fat. Do both. Win, Win. [gallery type="rectangular" link="file" ids="67637,67638,67632"] FAQ - Frequently Asked Questions Q: What is CAROL's Octane Score? A: It is the power in your legs that each heartbeat supports. Q: Really? 2x 20-second workouts will make me fitter A: Yes, if repeated three times a week over several weeks and if you are just starting out on your fitness journey. Q: Can CAROL exercises and protocols be replicated elsewhere, on other equipment and in other sports A: Yes. However, you might injure yourself when running. You will be unlikely to find a spin bike or bike trainer that comes with reHIT workouts and that is able to control the resistance levels changes as well as CAROL. Q: Is CAROL better than running on a treadmill or outside? A: What do you mean by 'better'? You will burn more calories from running for 15 minutes than from 5 minutes of cycling, as the former is load-bearing. CAROL's first job is to quickly get you fitter and stronger whilst reducing the risk of injury. Q: Are training shoes OK to use? A: Yes. I used mine for 90% of my CAROL rides. You can also use bike shoes that are SPD compatible with the pedals provided or swap the pedals for others that you prefer. I would say training shoes are better as they allow your feet to twist and that should reduce strain on your knees. Q: What are the pros and cons of HIIT? A: In a nutshell, HIIT is physically effective and reHIT is also time-effective. However, it requires motivation to repeatedly push yourself close to your limits. Q: How does reHIT work? A: Short, maximal efforts stimulate a disproportionally positive fitness adaptation in your body compared to the time-effectiveness of longer workouts. CAROL claim the mechanism for this is the response to muscle glycogen depletion. Q: Can I change the saddle? A: Yes standard saddles will fit. Q: Can I try CAROL before I buy? A: Yes. It has a similar 'fit' characteristic to stationary bikes you might have tried in a gym, so I'm not entirely sure what you'd gain from trying a CAROL Bike for 5 minutes. There are US and European showrooms where you can try one. However, CAROL offers a 100-day money-back guarantee if you are not satisfied. Plus CAROL assures me that very few people return their CAROL Bike. Q: Do I need WiFi A: Mostly, yes. You need to connect to the internet to sign up and periodically upload your stats to the web and download the latest leaderboard or updates to CAROL's software. You could probably create a WiFi hotspot on your phone if there is no WiFi where you exercise. Q: Does the CAROL bike support heart rate monitors? A: Yes you can buy CAROL's own brand or any other Bluetooth heart rate monitor. I would recommend a Polar Verity Sense armband over the heart rate monitor that is built into the CAROL Bike's handlebars. The latter isn't as accurate. Q: How do reviews of CAROL Bike on Amazon, Trustpilot and Reddit compare? A: Generally good! I'm sure you've already seen them. Q: Can I use CAROL in online group classes? A: Yes, CAROL states "As well as a free ride option, CAROL can be used with Peloton Digital and Apple Fitness+ classes and will soon let you join a Zwift or Kinomap race." Subscriptions to 3rd party services are not included. Q: What does CAROL stand for A: Cardiovascular Optimization Logic Bundles, Accessories & Warranty The standard and premium bundles include an extended warranty period plus some of the optional accessories. The most useful accessory would be an HR strap. You can buy the one from CAROL or any other standard BLE HR strap works - consider the super-accurate Polar Verity Sense arm strap. [caption id="attachment_77271" align="aligncenter" width="1024"] Get Optional Carol Bike 2 Accessories[/caption] Carol Bike Customer Reviews The Trustpilot scores for the CAROL Bike are good and average 4.5 stars out of 5 with almost 100 reviews. Customers love the effectiveness of the time-saving workouts, less so the subscription element. CAROL Bike Review - Take out OK, I'll round up this CAROL Bike review by re-iterating the key take-outs from my perspective. CAROL Bike did not increase my VO2max over 2 months. Nevertheless, I would bet that it will increase yours if you perform 3 reHIT workouts a week for 3 months. As a wannabe athlete (Ironman triathlete) I'm already fit and incorporate reHIT-like training in my regime. The CAROL bike is not aimed at people like me and I was surprised that my other family members preferred using the CAROL bike rather than one of my road bikes on a 'turbo trainer'. It was certainly much easier for them to change the saddle and ride position than when using my bike. The friend who recommended it to me originally, liked the small footprint and ease with which she could accommodate it in her flat without worrying about dirt and oil on a regular bike. She especially liked the significant time savings of not having to wear sports clothes for reHIT workouts, commute to a gym, or have to complete a 60-minute workout. The reHIT protocol does make sense as a way to start your fitness journey, and the science quoted by the CAROL Bike people agrees. You can't easily replicate these short, reHIT protocols on mass-market spin bikes and so, if reHIT appeals to you, you might as well go with CAROL as that bike has been specifically designed around this type of workout. You have the confidence of knowing that as you get fitter the CAROL Bike will still be great to use for other interval rides and longer endurance workouts too. You won't need any other bike. It's not cheap but then neither are the alternatives. The pricing of the competitors is similar but the quality of the CAROL bike's construction is clearly better than, say, Peloton. CAROL Bike 2 Discount Code & Pricing, Black Friday Sale Pricing There is a discount of £/$250 at CAROL Bikes automatically applied here, try and add my TFK code to give you £/$500 off in total. CAROL bikes are sold to professional gyms in London, the UK & the USA/Canada and to individuals for home use in those countries. The same flat price of $2,395 (£2195, CA$2949) is charged to everyone. The monthly subscription for households is $12/month and that covers up to 8 people. The 100-day guarantee. CAROL Bike is 100% confident that its product works. You get a 100-day period in which you can return the bike if you are not happy, the collection is free. 0% financing is also available. Get a CAROL Bike discount with the coupon code TFK directly from carolbike.com. The TFK CAROL Bike discount code can be used additionally to any deal that CAROL is running at the time - currently, that's £/$250 off - £/$500 in total! There is a holiday discount of £/$250 at CAROL Bikes automatically applied [gallery size="medium" columns="2" link="file" ids="77282,77283"]