More Good News If You Are

An elite athlete.

Shortly after writing my previous post, suggesting Tour de France riders live longer than normal people, I came across another study published in the British Journal of Sports Medicine. It was entitled “Mortality and health-related habits in 900 Finnish former elite athletes and their brothers”. The link is here.


They looked at male Finnish elite athletes who represented Finland between 1920 and 1965 and their age-matched brothers (not identical twin brothers necessarily). Fortunately having brothers seems common in Finland where it is often dark and cold.

They followed them from the start of their career up to 31st December 2015. 1296 of the 1800 died during the study period. The median age at death was as follows:


  Elite Athlete Brother
Endurance 79.9 77.5
Mixed Sports 75.9 73.7
Power Sports 72.2 72.2

Elite athletes smoked less and were more physically active in general. We don’t know why elite athletes live longer, but their overall lifestyle, which includes exercise, seems to be protective.

This is an observational study, and not an experiment. It remains possible that the difference in smoking rates or some other lifestyle factors made the difference, and the excess exercise narrowed the gap – the study does not exclude the possibility that exercise is harmful in excess. It also doesn’t tell you that endurance sports make you live longer than power sports – just that those that tended to do endurance sports came from families that tended to live longer.

But I’m still doing some triathlons this year. And I will still be advising my patients to exercise. I’ll dig out the paper, hopefully, and see if there are any more details buried within it that are important.





A New Post for 2018

I just thought I would share this question we were asked recently:

“Do you have any data on the incidence of AFib in people who say competed in the Tour de France in past years to see how the risks in this population compare with the public as a whole.”

There is no doubt that I see a lot of people with atrial fibrillation (AFib, AF). Most of the people I see are cyclists. And that makes me think that there is something about cycling that leads to AF. But, it could be a sampling error – all the people who get AF from other sports might go and see someone else. It doesn’t feel like that though. As I supervise the nurse led AF clinic. There are plenty of people who run too in Somerset – I only see a few of those.

Tour De France cyclists are an unusual breed. They may well be genetically different to you and I. Or at least me. And remember, at least (hopefully) until recent times, these riders were (probably) systematically doped. There were probably teams in France doping kids from the age of 11 (according to some of my French contacts), and many domestiques had to take drugs or be dropped. It started with amphetamines in the 1900s.

There are descriptions of arrhythmias in former cyclists (e.g. Europace. 2015 Mar;17(3):387. doi: 10.1093/europace/euu399. Epub 2015 Feb 12.); A left atrial tachycardia is often the start of AF. But, there are  no systematic studies that I am aware of. Overall, however, being a TdF cyclist seems beneficial to health however – they seem to live longer at least. See Eur Heart J. 2013 Oct;34(40):3145-50. doi: 10.1093/eurheartj/eht347. Epub 2013 Sep 3 and Int J Sports Med. 2011 Aug;32(8):644-7. doi: 10.1055/s-0031-1271711. Epub 2011 May 26. 

That doesn’t mean it’s the cycling though. It could be the diet, the genes, or even the drugs. We perceive drugs as harmful, but that doesn’t mean they are. When the stigma dies down, we should probably try them in the elderly. It might improve the quality of their life – sarcopenia (a loss of muscle) and a loss of cardiovascular fitness really hits the elderly hard in a variety of ways.

I’m afraid that endurance exercise does appear to predispose to AF – at least in men. The paradox is that those who exercise appear to live longer, which can get lost in all the concerns.

So AF may need to be reconsidered as one of those things that happens – like tendonitis, stress fractures and muscle strains (although a bit more serious, in my view).

If I don’t get AF this year, I’ll be doing the Dublin Marathon again in October.

Who does what on Crickles / Strava

You may have noticed on Strava that there is quite an extensive list of Sports into which activities can be categorised. Here, for no reason other than curiosity, is a chart showing relatively how many of each activity we have on Crickles:


Since the number of activities in each Sport ranges from Rides, which is in six figures, down to Handcycles, for which we only have one, I’ve used a log scale.

Cardiac Stress Score can be calculated for any of these Sports in which a heart rate monitor is used (and estimated imprecisely even if one isn’t).

UPDATE: the algorithm for calculating CSS in the absence of heart rate data has been significantly enhanced since the time of writing.

End of the year

I think most of us reflect on what we have achieved in the past year. For me, it’s been a mixed year with regards to exercise. I did my first sprint and Olympic distance triathlons. I completed my first marathon for 16 years (I only ran one before) – in just under 4 hours.

But I didn’t get my sub 20 minute 5K time. Close at 20:38. And my cycling went to pieces with the focus on running.

Just recently I spent some time looking at my run data on Crickles. Taking a few of the runs I plotted out the relationship between heart rate, speed and gradient. It’s a bit messy (although I have some ideas to tidy that), but the curve/surface is quite interesting. I plotted the curves initially to help statistically create a normal range for my running conditions, with a longer term view to help track abnormal heart rates for a given situation.

MATLAB Handle Graphics

I then limited the curve to gradients of +/- 2 degrees gradient initially. And I was struck by what it showed, but not entirely surprised.

my running

As I start to run my heart rate speeds up. No great insights there. There is then a plateau until just over 11Km/h. That fits with what I experience. I know from my Garmin that up to 11-11.5Km/h I can sustain. It’s comfortable. My legs wear out first.

Go too much above that speed and everything becomes harder. That is my lactate threshold for running. That’s where the pain starts and I have to breathe harder to clear the carbon dioxide generated by lactic acid in the muscles from my system. They have to work anaerobically at these sorts of speeds.

The curve kicks up again just over 14Km/h. That’s the respiratory compensation point. Beyond that I can’t clear the lactic acid from my system by breathing and I am on borrowed time.

And that is why I can’t do a 5K in under 20 minutes yet. Sometimes you hit psychological blocks as a runner. I have watched my son streak away in the last few months having joined a running club. He was stuck, probably because of his brain, but his heart rate data suggested he could run much faster. And they unlocked that speed in him. But I am stuck by physiology at the moment.

So, I’ll be sprinting and running up hills in the new year. And working on some algorithms to track my progress. My Garmin says I can do sub 20. I know I can’t. Yet.

Have a great Xmas. And good luck for 2018.

Let us know your goals and what you want to see from the site.


Heart Rate zones on the Navigator

There is a new feature on the Navigator for everyone on the BETA programme: you can now see your current training zones. The tab structure has been changed slightly so that when you’re not logged in the tab bar now looks like this:


Notice in particular the MORE option on the right. When you choose this you get the log-in screen that takes your BETA programme password screen. When you log in, the tab bar changes to this:


You can see that the HR Zones and Regularity tabs have appeared and I’ve selected the HR Zones tab. This shows my current training zones as calculated from the Crickles estimate of my current Lactate Threshold Heart Rate (LTHR). It also shows the date at which the zones were last changed – such changes are triggered from time to time in response to athlete activity data.

If you don’t yet have a BETA log in and would like one, please read this post and then, if you’re happy to proceed, send me an email requesting a password along with your date of birth.

Separately from the BETA programme, the standard Seasonal tab has also changed: Zone 5 was previously spilt into Z5a, Z5b and Z5c. These have now been consolidated for easier zone-to-zone and quarter-to-quarter comparisons:


Improved Relative profile report

The Relative CSS report – which is at the time of writing is the landing page on the Navigator – shows how the chosen athlete’s totalled Cardiac Stress accrued over the period defined by the Date range compares with others. This total CSS is a product of three factors:

  1. The number of activities
  2. The duration of each activity
  3. The cardiac intensity of each activity.

The first of these is straightforward. Information on items 2 and 3 is available on the Relative profile report. Here’s how it now looks:


In this case “Athlete” is me. The chart on the left shows how the duration of my activities over the chosen period (the last six weeks) compares with that of others, with the y-axis being scaled in hours. I’m in green. The widest part comes at about half an hour, indicating that more of my activities have been of this duration than any other. By contrast, other athletes – the blue shape – are doing a far greater proportion of their activities over a period of 1-2 hours. Unlike others, I have no activities – zero width – around the two hour mark over this period.

It’s important to note that the number of activities (item 1 on the list of three factors above) is not reflected here at all – from this chart alone it’s impossible to know whether I’m doing three times as many or half as many total hours as others. This only shows the proportion of activities at each duration.

The chart on the right shows the distribution of cardiac intensity. Again, the chosen athlete (me again) is in green and others are in blue. From this I can see that for me the widest part – the intensity at which I most frequently exercised – is at about 87% whereas for others it lies at about 82%. On the other hand, some other athletes have exercised at over 100% intensity in this period and I haven’t. (100% is not a magic value – you can think of it, approximately, as exercising at or above your established Lactate Threshold Heart Rate.)

Like most of the reports on the Navigator, it responds to your choices for Athlete, Date range and GroupGroup defines who is counted as “Others”.

This form of chart is likely to be unfamiliar to most people. However, compared to the old visualisation, it more clearly shows the relative distributions and has less risk of misleading at the extremes. Once you get used to it, it’s an intuitive plot that conveys its information nicely.

New on the Navigator

Following some early feedback from the Beta, a couple of new features have been added to the Navigator.

First, to make the Navigator quicker and easier to find, there’s a new big green button on the home page of this website:


(Depending upon your browser, you can probably see the picture of the buttons above as well as the actual buttons.) Old School access is still, of course, available using the web address

Second, when you’re using the Navigator there is now a small block of help text pertaining to each report. As in this example, this appears in the side panel and changes according to the tab that you’re looking at (in this case Fit-Fat):


General help on the use of the Navigator, such as how to reset the Date range quickly, is still available here.

Crickles BETA features

You may have noticed recently that there is a new report on the Navigator that requires a password, and that a few of the posts on this website are now password protected. This reflects some significant changes to Crickles that are being released initially in a BETA programme. If you’d like to participate and check out the new features please read on…

To access the BETA functionality

Send an email requesting access to

I will need your Date of Birth – this will enable us to factor in age into the new analysis.

This aside, you are only asked to agree to:

  1. Accepting the confidentiality terms;
  2. Giving me feedback;
  3. Acknowledging the limitations of the beta.

This is all described further in the Mechanics of the beta section below.

Please do try it out!

Here’s what’s in the beta:

More analysis of heart rate data

One of the main features of the BETA is a new Regularity report. This gives a new type of analysis on your heart rate data. It also gives some analysis on the “strap crap” that is filtered out by the Crickles data cleaning routines.

For those on the programme, a full description is available here.

Just your data

To date, all of the analysis on the Navigator has been available to everyone on an “all see all” basis. The new report is potentially more confidential in character and so each athlete can see only his or her own data. This is why we now require a password to access that report. In future, we may password-protect more information, such as FTP curves – subject to what people would prefer. However, peer comparisons are super-useful and we’ll keep these as a prominent feature.

Strava Friends

To date, you can compare yourself to others using the Group dropdown. However, apart from the gender sub-selection that this offers, this isn’t useful for most of the Crickles population. On the beta, once you’re logged in you can now choose Strava Friends from the Group dropdown. This then enables you to compare yourself specifically against your Strava friends on the relevant reports (Relative CSS, Relative Profile, All-in and This week). This is much more meaningful – and you can still compare yourself to the overall Crickles cohort and your gender group.

Mechanics of the beta

  1. Please email me as above to request a password. All passwords are encrypted in use and cannot be hacked in plain from a web server. However your password is not encrypted “in flight” when I send it to you. If you are concerned about security I can text you your password instead of emailing it, and if you’re very worried I can give it you by phone.
  2. At this stage I haven’t built a mechanism for you to choose or re-set your own password. Also, the password setting process is still manual and it may take me a while to get round to sending out yours if a lot of people ask for them.
  3. As far as I’m aware, this new analysis, and indeed some of the existing analysis, is unique and unavailable anywhere else. While I’m continuing to develop it, please treat it as commercially sensitive – for example, don’t email Strava describing it and asking for them to copy it!
  4. To log in, choose the Regularity report, which will throw the log-in screen (unless you’re already logged in). The User ID you need is simply your Strava ID (e.g. mine is 301194). You can see this on the Athlete dropdown in brackets. Once you’ve logged in you’ll be returned to the main page (Relative CSS) and will need to choose Regularity again to see it.
  5. While this functionality is still in beta, you can always escape back to the current way that the Navigator works by refreshing the page. This will log you out. On Safari at least, the browser caches your ID and password so you don’t need to re-enter them. The iPhone doesn’t do this – when we move beyond beta I intend to build this into Crickles so that you will rarely need to re-enter your credentials.
  6. You will also get a general-purpose password for accessing the protected posts on

If you sign up to try out the beta, please could you give me feedback on the new features. It would also be super-helpful to know:

  • what you use Crickles for;
  • what you never use;
  • roughly how often you look at the Navigator;
  • whether you ever use Crickles Activity Charts;
  • what further improvements would make Crickles most helpful.

Cycling is harder than you think

A couple of weeks ago Cardio Mark ran the Dublin marathon in a very creditable time of under four hours. I’m impressed. When I used to run regularly, I once or twice managed half marathon distance and I never finished wishing I’d done twice as much. Completing a marathon requires months of training and resolute determination.

A couple of days before Mark’s marathon I went for a bike ride. I had the day to myself so cycled over to Dunkery Beacon – the highest point in South West England and the region’s signature bike climb. It’s not the longest climb and not the absolute steepest but its combination of length and severity is nonetheless testing. The rest of my ride was not without interest, extending to 93 miles with 7.5k feet of ascent and taking me around 6:40 with a couple of stops. It was equivalent in difficulty to a reasonably stiff domestic sportive. Fit cyclists do not need to train for such sportives – they’re easy enough that you can just rock up and do them.

Out of curiosity, I compared Mark’s marathon with my bike ride using Crickles Activity Charts. Charting a histogram of our heart rates gives this, with Mark’s histogram in pink lying over mine in blue:


On the morning of my ride my resting heart rate was 46 bpm, which is marginally above Mark’s (44 bpm). Crickles shows our prevailing Lactate Threshold Heart Rates to be similar too (mine was 162 bpm and Mark’s was 157 bpm). The chart thus shows that not only did Mark record far fewer beats during his marathon than I did during my ride, he also managed his effort much more prudently with the entirety of his cardiac activity well under his LTHR in contrast to my ride in which I was well over my LTHR for a significant portion of the time. It is graphically evident that my ride placed a much greater load on my heart  than Mark’s marathon placed on his. This is reflected in our respective Cardiac Stress Scores – 570 for me and 300 for Mark. (Reflecting on this, I realised that the Crickles CSS methodology does not fully capture the restorative effect of my two coffee stops. I calculated the effect of these and it decreases my CSS by 17 points – just under 3%, so not a significant amount.)

By contrast, the differences in our Suffer Scores on Strava was much narrower – Mark’s Suffer Score was 255 compared to my 299. This confirms my previous finding that the Strava Suffer Score is not a good measure of cardiac stress.

There is an important point here for cyclists. Mark’s marathon felt hard and was hard because of the intense amount of corporeal stress that running for four hours places on the body. Skeletal muscle and the bones, ligaments and tendons to which it is attached, can feel the pain. There is also that intangible of “the wall” as it is harder to refuel adequately when running. Cycling inflicts far less strain on skeletal muscle and doesn’t pound our body in the same way. Unlike our peripheral muscles, our exercising heart does not feel pain and we thus have no direct real-time index of the stress to which we subject it. So long as we ride within our strength limits and eat and drink well, the wall of bodily pain that marathon runners have to run through has no analogy in cycling and there is nothing to indicate how much cardiac stress we’re accruing. The only direct evidence that our sportive was equivalent in cardiac stress to two marathons might be a histogram or a CSS number. An appreciation of this might spur us to think more seriously about the amount of recovery we need to build into our exercise schedule.