Chris Worfolk's Blog

Endure: Mind, Body and the Curiously Elastic Limits of Human Performance is a book by Alex Hutchinson.

It’s an interesting book for understanding the limits of human performance from both a physical and psychological point of view. Not that all questions are resolved. But there is plenty of discussion.

Below, I have picked out a few points.

Typically, you don’t run yourself to exhaustion. Your brain stops you before you reach that point. And that starts from the minute you start exercising. For example, cyclists set off slower from the start on a hot day.

But when you get in sight of the finish, you know the danger is over and you can sprint. Hence we can be hurting so much until the final straight, at which point we find that last bit of energy to push across the line.

How does this work? Is there some kind of internal regulation in the brain that we are not consciously aware of? Or is there another explanation? For example, could we be tapping into anaerobic energy?

It seems likely that the brain does have some control. For example, everyone finishes a marathon in just under 3, 4, 5 hours. Only the brain can respond to these abstract concepts. So why do so many more people finish a marathon in 3:59 than 3:47?

Similarly, how is it that the limit that climbing a mountain without oxygen turns out to be almost exactly the high of Everest? If Everest was a little smaller, or a little larger, would it turn out that the limits of climbing without oxygen were different also? It seems likely given that it was thought to be impossible until Reinhold Messner and Peter Habeler did it. Then they changed the sums to show it was just possible.

Finally, a note on hydration. We often hear the idea that if you wait until you are thirsty, it is too late. But voluntary dehydration seems to be fine in the short term. Top marathon runners sweat more than 3.5 litres per hour. They replace nowhere near this much. If our performance drastically drops when we lose 2% of our body weight, how did Gebrselassie become an Olympic champion when losing 10% of his body weight? That is not to say drinking to thirst is the perfect strategy for running a marathon: but it does seem to be fine for everyday life.

21 Lessons for the 21st Century is a book by Yuval Noah Harari. It looks at the near future (the next century) and the challenges that society will have to face.

Chiefly, this revolve around info-tech and bio-tech. What will happen when the majority of jobs are automated? The workforce had power when labour was required. But, as the rich upgrade their bodies to become superhumans and machines can replace the working man, how will this restructure society?

I highly enjoyed his book Sapiens: A Brief History of Humankind.

This one was thought-provoking, but not what I expected. I went in thinking there would be 21 clearly defined points that gave me something to think about. In reality, it was more of a ramble through various ideas, each spilling into the next. Interesting, but perhaps not as clear as I hoped it would be.

If you’ve been doing the Ironman Virtual Club races, you may have run into the problem where some of your activities have not registered, and you’re stuck on 33% or 67%. Worse, it doesn’t tell you what was missing, so you have no idea what went wrong.

One of the most likely causes is that your activity was too long. For example, if you run 20km for a 10km race, Ironman Virtual Club will not count it. I ran into this when I ran 1.7km for the 1.5km run 1 of Ironman VR3. And things got worse for Ironman VR4. Last week, they announced on Facebook it would be a middle-distance event:

It didn’t occur to me to double-check the details when signing up, so I went out and did a 5km run and 90km bike ride, only to flip down in front of the TV to watch the VR4 Pro Challenge and realise they were only cycling 40km! By this point, I was in for the full thing, so I finished off with a 21km run on Sunday. But none of my activities had registered with Ironman Virtual Club, even though I had completed the distance (and then done it again).

If you are using Garmin Connect, here is how to fix it:

Download the FIT file from Garmin Connect, then go to Fit File Tools. Remove the section of the workout beyond your required distance. In this case, I deleted the last 50km my bike ride and then downloaded the modified FIT file. To allow me to re-upload it to Garmin Connect, I then used the time stamp modifier to make it look like a new activity.

If you have Strava connected to Ironman Virtual Club, you could also upload the modified versions direct to Strava from the Fit File Tools website.

If you’re using something other than Garmin Connect that doesn’t produce FIT files, you can download the GPX file and use a GPX editor, like WTracks, to make similar edits. You can trim the start and end with WTracks, but I’m not sure how to modify the timestamp.

Cadbury produces a sharing bag of mixed chocolate buttons containing both milk and white buttons. As soon as you learn this exists you are probably thinking “are there equal numbers of each button in the bag?”

Do not worry. I have painstaking done the research. For months I have been analysing the frequency of each type of button in each bag to work out what the balance is. Finally, my research is ready to publish.

Here are the results:

A paired samples t-test to compare the number of milk and white buttons in each bag. There were more milk buttons (M = 55.38, SD = 1.30) than white buttons (M = 45.38, SD = 1.30).

Test for normality was run (p = 0.327) so Wilxin signed-rank was used (N = 8,

The lockdown seems like a good excuse to do some fast running. And, now that I have decided that I can live with the Nike Next%, I was eager to see if they really could reduce my 5km PB time. So, I decided to go out early Tuesday morning while it was still cool.

I felt crap when I got up. I didn’t think about abandoning, but I did think “remember this feeling for the next time you’re feeling crap, in case you ace it”. The weather was pretty good: nice and cool but there was also a strong headwind on the finishing straight.

I jogged up there but had to come down to a walk on Clarendon Road because the shoes were really digging into my feet. As I reached the top, it eased off a bit, and I figured it was going to hurt a lot anyway, so I might as well give it a go. After a few minutes sit down in the park, I counted down from 10 and set off.

My first kilometre came in at 4:08. After that, I had to back off a little as my chest started to burn. My previous PB was 22:06, so even on a great day, sub-21 was unlikely. Therefore, anything near 4:12 was acceptable. I settled in around the 4:20s, which I was fine with as even a 22:30 would show I could still run at around my best.

As each kilometre went by, where my watch said I was and where I knew the parkrun markers would be, drifted apart. I had specifically turned GLONASS on, as well as GPS, to get a more accurate reading but it was to no avail.

As I fit the final straight I smashed into the wind and felt like I was sprinting while simultaneously feeling like I was slowing down. I crossed roughly where the parkrun finish line is at 21:06, although I had to keep running to 21:29 until my watch registered 5km.

21:06

Which was one was correct? I’m going with the official parkrun course, which I assume they have carefully measured. It was a clear day, though, so there should have been a good satellite signal.

After the run, I collapsed on the grass and took 5-10 minutes before I could get up and walk again. Based on the parkrun line time, I was exactly 60 seconds faster than my previous PB. At 4%, the shoes would give me 53 seconds. That means I was the other 7 seconds of improvement. Or at 5%, 67 seconds, in which case I lost 7 seconds. But either way, my fast running is still in good shape. Of course, it is easier without the crowds, too.

And that’s the story of how I got up before 9am for the first time since the lockdown started.

Last weekend was the third virtual Ironman race. The first two were middle and standard, while this one was sprint distance 1.5km run, 20km bike and a 5km run. As with VR2, I decided to do it as a single block with timed transitions.

The first run was a bit of a mess. I thought I would go through the Dark Arches, around the station and back home. But it quickly became apparent that this was way more than 1500 metres, so I turned around in the arches and headed back. This gave me a 1.7km run at 5:19 per km.

The bike was a blast out to Horsforth and back. I took the back way to Kirstall Road, going around the Armley Gyratory, which makes for a lovely course when there are no cars on it. I only managed an average speed of 28.7 kph. It was never going to be race speed with all of the traffic lights, but also slower than when I did it last week. That time I was filled with anger and adrenaline at my computer, so maybe that is the secret to a good performance.

The second run felt a bit slow to start off but was anything but. I ended up running a 22:29, my second fastest ever 5km. That included my lace coming untied and having to stop to retire it. The same thing happened to me on my previous 10km run. They don’t mention that in the Nike Next% advertising!

My total time was 1:23:04. Alas, Ironman had a technology fail and only recorded two of my activities, so I didn’t get my digital badge (or at least won’t have it until customer support get back to me, and to be honest, it seems unlikely they will). Still, very pleased with the run.

The Chimp Paradox is a book by Dr Steve Peters. In it, he describes his model of the mind as two parts: the chimp, an irrational emotion-driven strong animal, and the human, the higher part of our brain that we often like to pretend is the “real us”.

It is a generalist book in that it is a useful read for anyone, not just those struggling with their own mind, but more of a popular self-help book with applications for every day relationships and problems.

I found it an interesting read, most of the time, but I don’t think I ever made it to the end.

I’ve launched my latest course, Google Tag Manager for Developers. It is predominantly aimed at web developers who want to save time but is also suitable for digital marketers and entrepreneurs who manage their own websites.

Google Tag Manager is a platform that allows you to quickly and easily manage analytics scripts and pixels. Even as a developer, who could write it all myself, I use Google Tag Manager to save valuable time and effort. The course covers getting setup, using some of the advanced features, and integrating Google Analytics and Facebook Pixel.

Here’s the video:

You can preview the course and find out more on the course homepage.

Ironman VR2 was a standard distance race with a 3km run, 40km bike and 10km run. I decided I wanted some real race practice, so decided to knock it out in a single session.

I set up a transition area in my car park, locking my bike onto the roof carrier and my stuff in my boot before setting off on the first run: a gentle tour around town. I must have been a bit sluggish as it came in at 16:08, although it was slightly over 5km.

Arriving back at my car park, I grabbed my bike, changed my shoes and set off on the cycle. I have started using the route down to Rothwell while the traffic is quite as it is much flatter than going north (it’s still Yorkshire, obviously) so it’s a good chance to use the aero bars a little more. I got some real back pain around 25km in, but it eased off towards the end.

After another transition, I was back in my running shoes and starting to fly. I finished the 10km in 48:10. That’s two minutes behind my 10km PB, but given I didn’t feel I was pushing that hard, and it was warm, and I had already been racing for two hours, I was surprised at how quick my time was.

Thumbs up to Ironman. I was a bit worried their software would get confused given I had recorded it as a duathlon, but it read it perfectly. Thumbs down to Garmin. I finally have my Edge pairing with my phone again, but the date is two days off, so it thought the bike session was two days ago.

My official result was:

2:36:12

That includes any extra distance I did but does not include the transition times. Good enough for position 7,179 out of 11,977 finishers. Although, the comparisons are meaningless given we’re all racing on different terrain.

Huge variations in estimates mean that we are 25% of the way through this to 2% of the way through this. All of this underscores the desperate need to start wide-scale antibody testing so that we can make evidence-based decisions on how we fight coronavirus.

The number of people likely to die depends on two factors: how likely you are to die when you get it (IFR) and how many people you will spread it to (R₀). Below, I’ll explain both of these and run the numbers based on current estimates.

How many people you will spread it to

R₀ represents how many people an infectious person will give it to. With seasonal flu, this is typically around 1.3. With highly infectious disease, such as measles, this can be as high as 9. Anything below 1 is great because it means the disease will slowly disappear as anything less than 1 means you are not even passing it on to one other person.

The Lancet has given an early estimate that COVID-19 at 2.35. But other studies have suggested it could be as high as 5.7.

The amount of people you infect is also dependent on the percentage of the population that are vulnerable. If half the population is immune because they have already had it or because they have been vaccinated, you can divide R0 by two. The number of people you infect is actually R₀ * percentage of the population that is vulnerable (R₀S).

R₀ is important for two reasons. First, the higher it is, the faster it will spread. We can artificially suppress the number to be lower by using things like social distancing and lockdowns. If we can get it down to 1 we can control the situation. This is easier to do at 2.35 than it is at 5.7. The problem with social distancing is that it only artificially suppresses the outcome. Once you end the social distancing, the number jumps back up and the whole process starts again.

Second, it defines the number of the population that need to be infected or vaccinated before the disease will start to disappear. At 2.35, we need around 60% of the population to be immune before the number drops below 1. At 5.7, that means 80% of the population.

How many people die from it

The second factor is how deadly the disease is. If you haven’t followed the coverage too deeply, you might think the death rate is anywhere up to 3.4%. But this is not the case. What you’re looking at here is the case fatality rate (CFR), which is the percentage of people who test positive and then die.

This is quite high in some countries that are not bothering to test anyone and quite low in countries that are widely testing. But nobody is pretending it is the infection fatality rate (IFR), which tells you of the people who get it (tested or not), how many of them die. This we can only poorly estimate because we haven’t tested enough people.

In the UK, we know we are missing a lot of people because we are only testing those admitted to hospital (plus Prince Charles), and the results from testing in Iceland suggest that 10-50% of people are asymptomatic.

Estimates on the IFR vary. In an article in The Lancet, Imperial put it as high as 0.66%. Oxford University, however, put the figure much lower, estimating it to be somewhere between 0.1% and 0.36%.

Combining the variables

Here is the data modelled at for both an R₀ of roughly 2.36 (60% of the population required to develop immunity) and for 5.7 (80% of population).

A few things should be noted: first, this only calculates the point at which the disease starts to disappear. It won’t disappear overnight. Even if we get R₀S down to 0.8, that still means that if 10 people get it, they will infect another 8. It’s on it’s way out but it is still throwing a few punches.

Second, if you want to be an optimist, you could say the IFR could be even lower. In the early days of swine flu, we were talking about high death rates (1-2%) and, in the end, it turned out to be 0.02%. This makes sense from a psychological point-of-view. Much better for a researcher to overestimate and say “sorry, it wasn’t that deadly after all” than to fail to raise the alarm, let everyone die and say “sorry, turned out it was super dangerous and it’s my fault everyone is dead”.

Other exit strategies

There are two other ways this could end. One is that it magically goes away over summer. Trump is still hoping for this option, I think, but even if this did happen, it may well just come back next winter.

The other exit option is a vaccine. Experts have said this is still 18 months away (12 if everything went perfect). But, importantly, this is just to deliver the vaccine. There is a difference between developing the thing and embarking on a nationwide or worldwide immunisation campaign. We have PPE equipment and COVID-19 tests now, for example, but getting them to the people who need them is still a logistical nightmare taking months.

So, we’re probably looking at two years until we’re immunised. For this to save lives, we would have to artificially suppress R₀S to less than 1 for that entire time, which means two years of varying degrees of lockdowns and social distancing.

Whether this can work depends on how easy it is to suppress the virus. If South Korea continues to limit their deaths to a handful per day, they could keep the total number down to 2,000. New Zealand seem to be doing even better. How well this will work in the long-term is unclear; China is now battling a second wave of foreign infections, for example, and normal life is far from resumed in any of these countries.

Conclusion

Somewhere between 40,000 and 400,000 people in the UK are likely to die with COVID-19.

At the best-case scenario, we could be in for another three weeks of grim death counts before the virus starts to disappear forever.

In a worst-case scenario, we’re 2% into this, which will either see us go through a full year of this many deaths per day or a two-year-long lockdown while we hideout waiting for a vaccine. Neither of these options is appealing because it involves a lot of death, or in option B, two years of social isolation, mental health problems, suicides, drug and alcohol abuse, lack of a healthcare system, missed cancer screenings, job losses, domestic abuse, children not getting their education and the many other social costs.

All of this underscores the need to start large-scale antibody testing to confirm what the IFR is. Once we know that, we can start making evidence-based decisions about what the plan should be.