When I last wrote a piece for this blog, 9 months ago, I’d just managed to climb Ventoux in a respectable time, claim a dubious cardiac efficiency victory over Laurens Ten Dam, and had started to dip my toe deeper into the uber geeky world of cycling power figures. From the hundreds of messages that I haven’t received, I know you’re all wondering how I could possibly top that, well here’s how.

Prior to my little heart problem, subsequent operations and resulting complications, I’d never really bothered with my power figures. I loved going as hard as I could for a climb, straight piece of road, or other random landmarks that would serve as a suitable finish line. I used to time myself with a stopwatch on climbs and loved beating my previous bests, before Strava came and took it to a new level. I had a turbo trainer set up at home that connected to my computer and I’d found the free software Golden Cheetah that could record & analyse my indoor sessions on Sufferfest, but this was for emergencies only. Luckily, where I live is perfect for cycling, it rarely rains and even if it does it’s still warm and lovely, so the turbo is for when work or other commitments restrict my cycling time.

Post-op my surgeon said I could push as hard as I wanted to, to try and drive my heart rate up into a normal zone, I don’t think he understood the sporting mentality, not many people in the “normal” medical world do. He probably wouldn’t have thought I’d be out a few weeks after my last op searching for the steepest bits of road I could and be dragging my 110kg carcass up them, trying to bludgeon my heart rate above 100bpm. I was, I did, but only just, and it was every bit as painful as it sounds. It was while starting out on the road to recover and wondering if I’d ever be able to do anything “physical” again that the turbo and those little numbers, initially pathetic, but slowly ticking higher each week took on a much greater significance for me.


Will wasn't able to go "full pain cave" due to a cardiovascular condition.

My first rides were painfully slow, maxing out at 180 watts and mid 80’s bpm – a resting heart rate and resting heart rate performance to match. As I kept pushing away my heart response gradually improved a little, training whatever functionality I had to react more quickly and to make my heart beat slightly quicker. Looking at my figures & estimated power up my “testing” climb to Gourdon ( 8k at 4% avg), they go like this (watts figures are Strava estimates):

  • August 2016 39:04 at 176 watts & 91bpm
  • September 2016 34:22 at 207 watts & 99bpm
  • May 2017 29:52 at 244 watts & 102bpm
  • August 2017 27:34 at 260 watts & 112bpm

This is still a little way off my best of 22:04 at 363(estimated) watts & 157bpm, but an improvement that meant that I could climb Ventoux in June 2017 with an average power of 238 watts for 2 hours & an average HR of 107bpm. At a glance it looks like a nice slow progression, with my power improving in line with my increasing heart rate. Looking at my never popular watts per beat (Watts/Avg Hr) figures I go from 1.93 w/b in August 2016, then 2.09, 2.39 & finally 2.32 watts per beat in August 2017. This shows my efficiency improving and seemingly plateauing, and remarkably my plateau figure is remarkably close to my pre-op PB figure of 2.31 w/b. Maybe there is something in this made up unit of measurement, or maybe it’s just a complete coincidence!

However, heart rate is not the only factor in cardiac output (the amount of blood pumped in a minute), stroke volume (the amount of blood pumped with each beat) increases up to 2.5 times during maximal exercise, so I’m certainly missing out on some blood flow in that department. I was a little worried that my improved performance was down to an enlargement of my heart, which is normal in athletes and gives a bigger stroke volume and so a bigger cardiac output. This can cause problems if the heart muscle gets too big, as, much like a balloon, if stretched too far the muscle walls become thin and can lose elasticity and their ability to pump effectively.


Zwift gave Will a nice and controlled environment to train.

I coerced my surgeon to give me an MRI scan to check this out, and happily they found no change or problems in my heart. Effectively the heart doesn’t “know” what the rest of you is doing, it only gets signals from the Sinus Node telling it when to beat and a few physical signals such as venous return which affect its output. The Sinus Node is the processor that takes the inputs from all your body’s systems and decides how quickly your heart should beat. Unfortunately, this is the bit that is damaged in me, so even when I’m butchering myself on my bike my heart thinks I’m out for a Sunday stroll. So as a result my heart rate doesn’t rise, and I don’t get any other stress effects on my heart, which is good for my long term health & maybe beating a lie detector test, but further reduces my cardiac output. You win some, you lose some! But even all this doesn’t tell the whole story

My heart response and ultimate maximum heart rate has been pretty similar for the last year now, with a long warm up I can hold a steady power with a heart rate in the high 90’s. To go any higher I need to push into what feels like anaerobic territory, this gives me a higher heart rate & so more power, but also starts burning the energy stores in muscles. Once the energy in my legs is gone I haven’t got the power to push my legs around or my heart rate up, and I go boom!  Without getting too technical, my biggest gain is that I can go much longer before the boom. It seems that I have a much bigger reservoir of energy in my legs, so I can dip into the red for extended periods.

Having slowly ground my way to a reasonable level in the real world, my very real “virtual epiphany” or is it a virtual real epiphany, happened very quickly. In September I re-found Zwift and on Zwift Power managed to go up Box Hill at 280 watts, by October I managed 323 watts for 20 mins, and by early November I felt like once I got up to speed on my turbo I could keep going, like the guy in Unbreakable, it felt hard but I could just keep going. The slow steady warm-up and pedalling at the same cadence & power pushing a flywheel much lighter than me really suited my condition.

Then it happened, I set up a Zwift ride with some old friends while simultaneously chatting on Skype. Whilst talking & not feeling like I’d gone any harder I saw that I did 345 watts for 20 minutes. Six days later I tried a race, 377 watts for 20 min, two days after that, 415 watts. As Robert Palmer would have said after a week like that, “I’m going to have to face it, I’m addicted to Zwift”.

For my dramatic increase in power, I’m not sure if it highlights my lack of conviction when it’s just me and the numbers, or the power of competition. I am after all an egg chaser at heart, so the sight of a skinny avatar having the nerve to try slipping away from me is more than I can take, and I just have to catch them. What I am hoping is that there’s not been some long term leak of fluid in my turbo trainer that means the resistance has slowly been edging down over the months massaging my power figures up. Or worse there is some as yet unknown problem with fluid trainers that means that when they get hot there is an uncharted loss of resistance… Having written that last line I Googled turbo trainer accuracy (a lot) and read few things which a) make sense and b) throw a different light on what I’ve written above!


Will quickly climbed the ranks, slowly improving his real-world performance.

Firstly, yes, fluid turbo trainers are harder to push when they are cold, and easier when warm. The more watts you put through them the hotter they get and so the easier it is to go quicker. So not only is my heart warming up, but the turbo trainer is as well, and my feeling of going quicker and being able to sustain it is only partly from me. The question is: How much of it is me? and to answer that I need to know if Zwift and Golden Cheetah are calibrated to the cold or hot turbo power curve? or try to estimate between the two? In fact, there are a lot of questions: How long does it take to warm up? What is the difference in estimated power between coldest and hottest?....

The problem is that being a watt-geek newbie I’ve only got estimated power figures from Strava, Zwift & Golden Cheetah to go by, and I’m pretty sure that comparing two different estimates won’t get me very far. I did a little test during a warm down after a Zwift race; in 4th gear pedaling at 70rpm my power was 160 watts, I immediately went into Golden Cheetah and did the same – 175 watts.  That doesn’t help at all, unless Golden Cheetah has an algorithm that tracks heat build-up, assumed my turbo was cold and so gave me a higher power reading…Oh, I’m in deep!

In terms of my recovery or attempt at cycling with a heart problem, it’s not really important, I have improved enormously by every measure. But now that I can push some reasonable numbers, and hold my own in a virtual race, what would kill me is not being able to compete and have my fun. So there are a few burning questions to ponder while I’m on my bike; What am I actually capable of? Can I really put out those figures on a turbo (449 watts for twenty minutes now!)? Will rolling a flywheel and having a controlled power output really help me that much? Should I publish my paper on “Cycling Wattage & Torque Output Comparisons of Fluid Based Trainers Against Real World Environments (Especially in Fatter Males)” Johnson et al 2018?


Will just getting pipped at the line by Team Dimension Data rider, Steve Cummings

The only solution is to answer the big question, go to the next level, go nuclear, go power meter. On a whim I stopped in a bike shop I pass by in Golfe-Juan called Golden Cycles, a name that always amuses me for some reason! I asked about power meters and if anyone sold or rented them near here, the man said that there’s no demand for them in France, but he knows that we British love our figures, and gave that little smile that said “you crazy Brits…”.  This was frankly a double bust for me, as I was speaking in French and he picked my accent in a split second, and then correctly marked me as some kind of watt-geek who can’t enjoy the beautiful sport of cycling without putting numbers to it.

So this is where I am currently; I have two possible watt meters that I could borrow in the coming weeks, cranks and a PowerTap wheel. I am still holding out hope that I’m not a big enough watt-geek to fork out the best part of a grand for an irrelevant device, let’s see how that goes! I want to check the accuracy of my Zwift figures, pure & simple, once and for all, and then I’ll know. This, however, throws up a few dilemmas; what if I am currently a Zwift Bandit, hated by all the silent avatars around me, we all saw what happened with Cameron Childs & his Alpe du Zwift KOM. How much of an error can I accept as normal, and how much is too much? If I am a faker should I flag all my Zwift rides and lose all my times, and why do I care so much!! Even worse, now that I’ve told everyone about it I’m going to have to come clean with my results.  Who’d have thought a heart condition could be soo complicated #ItsNeverEasy #TooOldForHashtags.


Cheers Will! Here's to many more good miles (virtual or real).

June 18, 2018
Tags: Road/CX