The CAROL Bike Examined: Can It Really Get You Fit in 9 Minutes?

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I recently tried the CAROL bike – a new exercise bike workout that claims to get you fit in as little as nine minutes! This really is a workout for the time poor.

Because it’s so short the theory is you don’t sweat so, if you want to, you can do it in normal clothes and shoes. My chin would beg to differ with the no sweating thing but other than that I did it in normal clothes and went straight out afterwards!

CAROL bike in a white lounge

There’s a lot of big claims for CAROL – the manufacturers say it will give you the same fitness benefits as a 45-minute jog – in just nine minutes (only 40 seconds of which is tough).

But can it really live up to its claims?

How Does The Carol Exercise Bike Work?

It’s based on a fitness technique called the Wingate Protocol which is usually used to test fitness, but also works at improving it done regularly.

When I tested it (back in 2013, but this post has been updated in 2019), the plan saw you pedalling slowing for two minutes, then going hell for leather for 40 seconds.

As you pedal a computer programme attached to the bike adjusts its resistance to keep you working at maximum intensity. This is one thing that makes it different from just cycling intervals on a normal bike – you can’t shirk off, the bike knows what you can do and forces you to do it.

You then pedal slowly for a further two minutes to recover, do another 40-second interval, then cool down for two minutes. The first interval was fine, the second was the longest 40 seconds of my life. This was tough.

Now, the mathematicians among you might have immediately noticed that that does not add up to nine minutes – that’s because, I tested CAROL when it was very, very new. They have now changed the recommended protocol to two minutes warm up, twenty seconds fast interval. Three minutes recovery, then 20 seconds fast interval, then a three-minute cooldown.

At the time I tested this bike I was running half marathons, this means I have great endurance but put me on something like this that requires spring training and I underperform and woah, it was tough.

How Does Such a Short Workout Do Anything?

The CAROL bike is a form of anaerobic exercise. This type of exercise quickly pulls fuel from your muscles and even just over short periods a few things happen.

It stresses the heart and lungs – in a good way – forcing them to work harder, which builds fitness fast. This is the principal of all high-intensity interval training but, CAROL uses a slightly different form called REHIT (I’ll explain that in a minute).

You also use sugar stores from your muscles very quickly when you work anaerobically. As the sugar gets broken down it releases molecules that signal to your body to increase your sensitivity to insulin – the hormone that normally shuttles sugar into your body. This is important as the less sensitive you become to insulin the more you produce – increasing your sensitivity to insulin lowers risk of type 2 diabetes but also your chance of fat storage.

CAROL bike on a white background

What Evidence is There That CAROL Works?

CAROL was invented by a man called Dr Neils Vollaard who works as a Lecturer in Health and Exercise Science at Stirling University in the UK.

As I said, before it was based on the Wingate Protocol, but refined into a training technique he called Reduced Exertion High-Intensity Interval Training or REHIT.

REHIT came from the idea that High-Intensity Training was brilliant at improving fitness in a short amount of time – however, most of us don’t do it well enough to get optimum results.

Most HIIT protocols when done properly see you working as hard as possible for four to six bursts of 30 seconds with 2-4 minutes in between (remember when I first tested CAROL you worked for 40 seconds).

It’s unsustainable for most people to actually work that hard for that long – plus it’s still a 20-minute workout – so, Dr Vollaard started investigating what happened when you shrank the intervals – did it make any difference to the results? And the general consensus was so long as you maintained maximum intensity, it didn’t. The idea of the CAROL bike is to keep you at that maximum intensity.

According to a statement from Dr Vollaard on the CAROL website, “in our labs, we see insulin sensitivity improve by 25-28 per cent and fitness by 15 per cent within 6 weeks. The CAR.O.L stationary bike reproduces these results in the real world.” 

Of course, a company can say anything on their website, it doesn’t mean it’s true – however, the study proving the above was published in the European Journal of Applied Physiology way before the bike itself was launched and has been subject to peer review.

There’s also a lot of other published research uses REHIT on methods unrelated to CAROL showing that it does work. Click here if you want to see all the papers.

CAROL also have an ACE in the hole, so to speak. They actually got the bike tested by the American Council on Exercise (ACE) which is the main governing body for fitness instructors in the US. It’s highly respected. Their research came out in February 2019.

The study compared what happened when people used CAROL three times a week as directed, compared to people working out aerobically five times a week for 30 minutes and found that yes, it did increase fitness more effectively.  They also saw a greater reduction in waist circumference, blood pressure, cholesterol level and other blood fats. If you want to check out the research, it’s explained really clearly here.

Dr Michael Mosely, best known for his book The 5:2 Diet but also an investigate science writer, also tested the bike for the BBC and found that over five weeks, people improved fitness by 11 per cent – enough to reduce risk of heart attack by 20 per cent.

It sounds too good to be true, but generally, the evidence stacks up that it works. I say generally because if you inspect the original study quoted above closely it doesn’t quite show the exact results mentioned on the website.

It tested both men and women and while it improved fitness in both sexes (15 per cent in men, 12 per cent in women), the 28 per cent fall in insulin sensitivity only occurred in men – women didn’t get the same response. A second study though showed no difference between men and women. The ACE Study also tested both men and women but they didn’t break the results down by sex. 

The Main Downside of CAROL

The cost!!!

When I first tested CAROL it was being used by bankers and other super elite City types who had installed the bikes in their offices as it was the only way they could find time to exercise. You couldn’t buy it as a private individual but that’s changed and you can now buy it for your home. Sit down though as the bike costs £2995 to buy for your home.

Why Is It Called CAROL?

Oh and just for the sake of accuracy CAROL is the name of the computer programme that runs the workout not the bike itself. I quite like the idea of workout equipment with names though. I shall henceforth refer to all treadmills as Tina and rowing machines as Ron. And then this blog will make even less sense than normal.

It’s also technically spelt CAR.O.l  – which stands for Cardiovascular Integration Logic – but if I use its proper name no-one will ever find it via google!!! 

Images: @CAR.O.I used with permission

Who is The Wellness Nerd?

My name is Helen Foster, and I’m a health journalist and wellness author. Publications I’ve written for include Women’s Health, Reader’s Digest, Body and Soul, Good Health at the Daily Mail, and more. I have also written 16 books on health and nutrition.

2 thoughts on “The CAROL Bike Examined: Can It Really Get You Fit in 9 Minutes?”

    • I only tried it once a long time ago – that’s why I base most of the post on the science. It was tough though.


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