I can get a bit geeky about the data. You may be interested in the stats I gathered while running the Pilgrims Challenge. First of all elevation…
All told, over the two days, during the 66 miles there was 7588ft of ascent. That’s the equivalent of a Ben Nevis with a Snowdon on top. This could have had quite an impact on my heart rate and I learned a lot on the Druids Challenge about going out too fast, having my heart rate racing the whole day, so my intention on this one was to take it slow. I managed to keep this steady by setting an alarm on my watch that was connected to a heart rate monitor on my chest. From my earlier blog about heart rates, this is important because a high heart rate means that I am using the anaerobic energy system which only lasts a limited amount of time because of the limited supply of glycogen, whereas a lower heart rate indicates the aerobic system is being used which uses my near infinite supply of fat. One can’t last very long in the desert unless one is running aerobically. My lactate threshold, or the rate at which my heart starts to burn glycogen rather than fat as it’s main fuel source, is around 160 beats per minute. I set the alarm on my watch to alert me every time my heart rate went above 160 bpm so that I could slow down or walk until it dropped down into an aerobic zone. On day 1 my heart trace looked like this:
It averaged 150 and I had a moment when my heart rate went up to 163, probably somewhere near the top of Box Hill! What an improvement on Druids where I averaged 174 and maxed out at 192! Day 2 was even better: I averaged 139 and topped out at 153 bpm. Maybe something to do with all the meditation. With the lower heart rate and the fatigue from the previous day, you’d think I might have run significantly slower on day 2, but I was only 16 minutes slower than day 1.
- Day 1: 7 hours 11 minutes 08 seconds
- Day 2: 7 hours 27 minutes 14 seconds
For those that measure steps, I took 70819 steps on day 1 and 76238 steps on day 2. I lost around 4 lbs over the two days, burning 6544 kcals on day 1 and 5756 on day 2. Given that I will be taking around 2700 kcals per day with me to the desert, it’s clear that I am going to be in significant calorific deficit during the week, so I’m going to be losing quite a bit of weight over the seven days of the Marathon des Sables. I’ll talk more about my race nutrition plan in a future post.
I also gathered data on my cadence, or the number of steps I took per minute. According to Shane Benzie of Running Reborn, who has coached a number of desert runners, and winners of MdS, the ideal cadence is around 180 steps per minute, to maximise mechanical efficiency and reduce the likelihood of injury. I usually run at around 180-185 but in Pilgrims day one I was down to 160 steps per minute, but I did max out at around 256 spm which coincided with coming down a very steep hill! My cadence was marginally up on day two at 167 spm.
Interestingly, at least I think so anyway, I spent more time on my left foot than my right foot on both days. I spent 51.8% of the time on my left foot compared to 48.2% on my right. I’m not sure what this means other than my right knee is the one that has had the most surgery.
Importantly, since Pilgrims, my recovery has gone really well. I had a recovery week immediately after totalling 17.4 miles, followed by a gentle ramp up to 32.4 miles the following week, and 34.2 miles the week after. I’ve now got fewer than 40 days to go, so there’ll be a few more miles before tapering and acclimation prior to flying out to the desert on 6th April.
If you haven’t already, you can sponsor me if you feel so inclined at https://www.justgiving.com/fundraising/damoisrunningmds.