VO2 Max

My VO2 max, as calculated by Garmin, is hovering between 45 and 47.  I’m not entirely sure of its accuracy, and I’m sure that it is designed to flatter, but I’ll happily accept 85th percentile in my age group.

Cadence and heart rate

An interesting mini article at the bottom of an interview with Dan Martin in the July 2020 issue of Procycling.  I have heard it said many times before; high cadence riding is most efficient but requires higher levels of oxygen. 

Historically, I was always a “masher” using very big gears, I rode a 88 inch fixed gear around the peak district and my 12 speed had a lowest gear combination of 42 on the front and 19 on the back.  I was regularly out of the saddle using brute strength to power the pedals round.  Years later I was still riding the 52/42 but had moved away from the time trial block to a 12/21T

In 2008 when I got back to cycling after a break, I managed to bend my frame and the costs of repair were massive compared to the option of buying new.  So I bought a cheap Bianchi; this was my first ever aluminium bike and also my first with brake lever shifters.  The main difference, apart from the weight, was the gearing. It had a 38T chainring and a 23T sprocket; this seemed a ridiculously small gear to me at first, but I got used to it. 

In 2012, I bought a new bike which came with a compact (50/36) and a 12/28.  I was going to swap it out to an 11/23, but left it for a few weeks to give it a try.  It did seem a little odd again, but I could pedal uphill while seated, very comfortably and only needed the bottom two gears for serious hills like Winnats Pass. 

Over time, I started to use the lower gears and spin a little more, but I still used to power uphill, generally out of the saddle. 

Then AF hit me.  At first I didn’t know what it was, and the effects were relatively mild; I assumed I was ageing and getting less fit.  Eventually, I found myself with a 30T sprocket and using it more often, although it didn’t really feel comfortable.  Then finally, persistent AF made itself known and my fitness dropped off a cliff.

Three years later and I am back to normal.  I still have the 30T and I am using it regularly on the steeper slopes, I rarely climb standing and I spin rather than mash.  I don’t think this style is inherently any slower than my previous style. 

One interesting point is that spinning is supposed to require a higher level of fitness and more oxygen demand, but I am not sure it is that simple.  When I spin up hill, I can keep my HR low, but when I stand, it rises above 160 almost instantly.  It seems to me that standing and mashing requires more oxygen than sitting and spinning, possibly due to the fact that I am also supporting my bodyweight.

Overall, I think my current style is more efficient and I am working to refine it.

Cycling Weekly

Another mention of AF in Cycling Weekly this week 11th June 2020.  This time as a possible outcome of overindulging in alcohol.  I have long believed my own AF was caused mainly by over-exercising and a genetic predisposition; my mother also had AF and was a committed athlete in her youth.  I had also considered that alcohol may have been a factor for me (not for my mother, she was a lifelong abstainer)

I was always fond of a drink and there are several ways it may have impacted on my heart.  Firstly, I drank too much as a youngster which may have had a toxic effect long term.  Later in life, I drank much less, but still more than government guidelines and with some occasional nights of bingeing.  Finally, I would often go out for a group ride after several drinks the night before.  Although I would not be hung over, I would be slightly dehydrated and my heart trying to push too little volume may have contributed to my ill-health.

After diagnosis, I pretty much cut out alcohol, and my abstinence continued for a long period afterwards because I did not want to further compromise my liver considering that I had large quantities of amiodarone left in my system. 

Now, three years post ablation, I have very few drinks.  I log every drink that I have and largely remain under the 14 units per week limit, admittedly with a few lapses on special occasions.  I also log the number of ectopics or other ECG anomalies I pick up on the Kardia.  Luckily everything remains fine. 

Further improvements

Last May I published a post bemoaning the fact that I had not returned to full fitness; I wasn’t sure whether it was my relative lack of exercise or slight excess weight that was the cause or just that I was not completely back to normal.  Although I was incredibly happy with my condition compared to what I expected on diagnosis, there was the niggling worry that my recovery had hit a plateau. 

My resting HR, which had been falling steadily since the ablation, had still not returned to “normal”; it was 70 instead of 57.  My bike rides were 2mph slower than they used to be and my hill climbing was quite poor; although a small part of this may have been related to restricting my HR to 165 rather than 185.  I was also experiencing regular runs of ectopics.  As it was then nearly three years post ablation, I was not expecting to see any further recovery.

Over the last year, I have continued to improve my cycling capability.  I am still self-limited to a HR of 165 but my average speeds are a little higher, perhaps only 0.75mph down on a few years ago.  My recovery from exercise seems good and my Garmin watch says my VO2 max is “excellent” at 47, although I did not have this facility until recently so I can’t compare this with previous data.

My monthly level of ectopics is also down at a post-ablation low: 0.6 per minute this year as opposed to 1.7 in 2019 and 1.4 in 2018.  I believe I was completely free from ectopics prior to AF, but can’t be sure of this; my pre-AF pulse seemed rock solid, but in hindsight, I may have subconsciously disregarded any pauses.

Recently, due to the coronavirus lockdown, I have stopped my rides on flat trails as they are too crowded.  I have resumed cycling on roads, which is normally slightly faster in spite of the hills.  My lower max HR does not seem to really be a limiting factor and I am now wondering whether the ease at which my HR elevated in my youth was possibly a sign of lack of health.  In the eighties, I was very proud of my RHR of 42 and max HR of 190, which were both much more extreme than others in the gym I went to.  In retrospect, this was very unhealthy and I think the primary cause of my HF.  Below is my May training log from Strava.

Strava milestone

I was just looking at my Strava account and noticed a milestone: 20000 miles since joining in mid-2008.  It’s not a big average and doesn’t compare with the stupid miles I did in the eighties, but they’re not on Strava and apparently therefore didn’t happen

Lockdown activity

Due to social distancing, I have not been able to join a group ride since the middle of March.  Before the coronavirus, work, family commitments and illness meant that I haven’t ridden with the club since the end of November (was this antisocial distancing?).

Usually I only do long rides with the club, and tend to stick to around 30 miles when solo.  In the lockdown period, I have been going out every day, alternating cycling with walking.  I believe I am getting a little fitter; every day I take a Kardia reading while relaxing in the evening, I have been recording these for several years now.  It seems that over the last couple of months, there has been a significant drop in my relaxing HR.  Also my Garmin watch tells me my resting HR is down at 57, which is exactly the same as prior to AF in 2015.

Another metric I trace is the average and maximum HR during a ride.  My tested max HR while still healthy was 185; prior to AF I would average around 156 and peak at 175 on hills and occasionally I would hit close to the maximum on a specific effort.  In 2015 I sometimes hit exceptionally high rates of up to 220, but these were momentary and did not affect my performance, so I assumed that they were faulty readings, and thereby ignored the early signs of AF.

Recently I have decided that a return to my “normal” exercise would be a return to the conditions that led me to develop AF, so I have restricted my max HR to 165.  I have changed the gearing on my bikes from a 28 tooth sprocket to a 30 tooth.  I am also using this regularly and spinning up smaller hills, whereas in the past I would have powered up most hills mashing the pedals in a 23 tooth, using the 25 and 28 as bail-out gears for the extremes of the peak district.

I am much slower on the hills than I was, but I am also a few Kg heavier, which may be more relevant than my aerobic fitness.  Overall, my annualised average speed is continuing to rise, but I am still 1.3 mph down on my previous healthy average.

On this graph I am considering my health to be fine up until the end of 2014.  There was a slight reduction in average speed up to that point, but that was likely to correspond with taking longer and more hilly rides.  I suspect that I will continue to improve my fitness over the summer, without stressing my body too much.

Three years since treatment

I didn’t even notice this anniversary, but my daughter pointed it out to me; it is now three years since my mini-maze.  I also had a catheter ablation for flutter and re-isolation of one of the pulmonary veins six months after this, but this was planned from the start.  I have been pretty much AF-free since this procedure; I have had a few wobbly heartbeats picked up on the Kardia, but these were not accompanied by any symptoms and were generally dismissed as normal by the cardiologist. 

My fitness has taken a nosedive; admittedly from a very high pre-AF base, although as endurance exercise was probably the cause of my AF, this may be a good thing.  I have not tried to regain my original fitness level, worrying that this would also bring back the AF, but I have been out cycling and walking regularly.  I started off very steadily, over short distances with no hills and gradually increased the intensity.  Last summer I went back to the bike club, but for the social rather than the faster pace rides.  Last year I did 2700 miles at 14.5 miles/hour, this is a 1000 miles and 1½ miles/hour worse than in 2015, but it is a comfortable level and I am very happy with my abilities, compared to where they could have been.

I was an unusual case; the mini-maze is not common in the UK.  It was difficult and recovery was relatively slow.  I did feel that the debilitating aspects of the procedure were not really made clear, and I think someone a little older or less athletic may have struggled.  However, I have no AF and very few ectopics, my fitness is probably above average for my age and if anything my ECG is still improving.  I take no drugs and due to the LAA occlusion, I don’t even need anti-coagulents. 

The clinical trial I was part of has now finished, the report has not yet been published, but I know that in the UK at least the mini-maze has been markedly more effective that the catheter ablation approach.  Although I would like to read the final report, I think that I would recommend the mini-maze wholeheartedly to anyone suitable, with the caveat about recovery being more difficult. 

AF Strava group

I sometimes google Atrial Fibrillation and cycling to see if there are any new websites or medical papers that might be of interest. I discovered yesterday that there is a “club” on Strava for cyclists with AF. It was set up by a sufferer who thought there was a lack of information out there for people like me.

Unfortunately, there are only 11 members, including myself, but it could be a useful resource if more AFibbers joined and contributed.


Post viral Xmas

I recovered from the effects of the pre-xmas virus within a couple of days.  I was quickly back to what felt like normal, so resumed exercise and had a week away from work overdoing the Christmas spirit.  My blood pressure has remained at 130/80, which is slightly higher than normal, but could be something to do with the festive alcohol.  I also had a few ectopics on the 29th that I think could also be related to alcohol. 

The graphic from VeloViewer shows my cycling activity from last year.  Definitely disappointed not to hit 3000 miles, especially as I had actually planned for 3500.  My annualised average speed is still rising, but still 1.5 mph down on 2015.  I could probably go harder, but it does not seem worth the risk.  I still get the occasional high HR when exercising, but only for six seconds; it is probably nothing, but again, not worth the risk.