Fat asses running for Science

This week-end, several of us went to the Pacific Spirit Regional Park for a 75k ultra organized by the Cardiovascular Physiology and Rehabilitation Lab at UBC. I counted at least 5 CFA members at the start on Saturday. A second run was organized on Sunday with a separate group of runners.

The cardiovascular system was the subject of the study: for each test, we were laid down on a table, had our blood pressure taken, then an electrocardiogram was recorded while pressure sensors monitored the carotid, femoral and radial arteries. A doppler ultrasound of the carotid was also performed. This test sequence was repeated numerous times: several days before the race to establish baseline numbers (a VO2max test was realized at that time as well), in the middle of the run after 45k, and immediately, 30 minutes and 60 minutes after the end of the race. Our heart rate was also recorded for the whole duration of the race.

In addition, we were subjected to cognitive tests on a computer evaluating reaction time, decision time, and short term memory (with a test inspired from the Memory game; you know the one where young kids always beat everybody else).

The route was a nice 15k loop around the park, including some overlap with the well-travelled Foolish Gerbil loop, but also extending to the north half of the park. Mostly on trails, mostly flat, but with a couple of short hills, including the Admiralty, the highlight of the day.

There were 3 well-stocked aid stations along the course (the first one was passed twice), so in addition to the loop starting point, we would get aid every 3k or so. I had not done a long run with frequent aid stations in years: it's nice to not have to carry your water everywhere... The aid stations were also there to keep track of what we were eating and drinking during the race, which we would report to the volunteers at the stations (researchers themselves and UBC students), and we would read out our heart rate and tell them our perceived exertion level (a suggestive scale of how hard you feel you're working).

The run was very well organized, we only looked for tape a single time: it's always when the route goes straight that organizers think "Heh, they don't need tape, they just have to keep going in the same direction", and runners think "Wait? Did I miss a junction, was I supposed to go right? Am I getting off course again? Why don't they put a f**ing piece of tape right here at this crossing so that I know where to go? Didn't they tell us that tape would be on the right-hand side? This piece of tape is on the left, isn't it? Is that the middle?" Anyway, we just had to go straight.

It was my first 75k, but I had run 50k of the Vancouver 100 in June, so I figured I could finish this run. It was a lot of continuous running though, with little climbing to get a break, so I was expecting to suffer hell at the end of the day, with very stiff legs. As it turned out, I never felt better at the end of a long run.

We were fitted with heart monitors, and I had never run with one before. It was very interesting to keep an eye on my heart rate on such a long run. Five minutes in, Karl told me his was showing 126 BPM, mine was at 145. So, there is an age difference between us, but I took that as a clear indication that I should probably slow down. So I quickly fell in last position, trying to stay slow.

But I caught up with Karl at a junction, as he was looking for the next piece of tape. Against my best judgement, I kept up with Karl up to the next aid station, around the 9k mark. Karl announced 135 BPM and a perceived exertion of 9, I announced 155 and 12. The student staffing the aid station even said in his radio: "There is a runner with a heart rate of 155..." -- I imagined that he was expressing some kind of concern. Then I really slowed down and let Karl get ahead. I decided I should try to learn from the expert. I had in mind a rough image of the max heart rate curve with respect to age, but I couldn't remember the exact numbers.

I figured I'd better get my perceived exertion down just in case. This is a subjective scale, that is best used when renormalized using some kind of objective measure (like 85% of max heart rate as a common point of reference, or something like that), because everybody will describe their exertion levels differently. But I suspected that if he said 9 and I said 12, I may have been pushing too hard.

At the beginning, it felt like 145 BPM was a good slow pace for me. So I tried to maintain that, more or less. As time went by, however, I started to feel like I could maintain 155 without much trouble. And it was also easier to keep fast stride rates at a slightly higher speed, and that gave me a smoother ride. It just felt better.

At the end of the first lap, I was a little over 5 minutes behind Karl. I sped up a bit, and caught up with Karl again a few kilometers later, with my heart rate close to 160. We ran together for a while. We nearly bumped into an off-leach and out-of-control dog, whereby Karl expressed his frustration with the owner's lack of control, who appeared to be daft enough that I felt I should express my own frustration as well, just in case two voices would be more convincing than one. I'm afraid that man was a little too dense to understand the problem with a high speed collision between dog and runner.

A little later, after taking some time explaining to me why it was always best to start slow for an ultra, even taking pains to illustrate with concrete examples from his extensive running career that I really should take it easy for now, Karl felt that I wanted to try my luck anyway, and encouraged me to keep going if that's what I wanted. Knowing full well that he would probably catch up with me before the end, I picked up the pace.

I essentially spent the rest of the day running away from Karl, who in my head looked liked the light of an oncoming train in a tunnel that I was desperately trying to get out of in time. Ultrarunning will make you a tad delirious, yes.

At the end of the second lap, I was only a few minutes ahead of him. For the third lap, I sped up a bit more, with my heart rate often between 160 and 165. Above 165 was getting too high though, and I could feel my energy levels drop down rapidly. So I used 160 as a target rate when pushing hard, and 150 when taking it easy.

At the end of the third lap, we were stopped for 30 minutes and subjected to the usual battery of tests. I experienced some interesting tunnel vision effect while looking at the computer screen. And while listening to the doppler audio feedback, it sounded a bit like I skipped a heartbeat or two, and that was a little unsettling actually. Apart from that, a 30-minute interruption in the middle of an ultra was not that hard to handle.

I experimented with some real food, which I'm not used to, and a toasted cheddar cheese sandwich worked great for me.

At the end of the fourth lap, Karl may have been 5 minutes behind, at most. I turned around to look back quite a few times during the fourth lap, because I knew I was slowing down while trying to keep some reserve for the last loop.

What really picked me up is to see Dario come in for the finish (and the first place) just as I was leaving for my fifth loop. I had started the day convinced that he would eventually lap me, of course, along with the other fast runners. So it felt like an achievement that he didn't.

I don't have my split times yet, but my fifth lap was strong. I finished feeling great, and still ahead of Karl. He was of course right: after all, I did start slow and accelerated at the end. With the exception of my 3rd lap, which was probably too fast, I ended up following his recommendations, I just didn't really know what a good pace was for me that day, and it took a couple of laps to figure it out.

I'm now inclined to believe I can complete a 100k without too much suffering, which I'd like to do sometime later this year. Probably at the Seawall 100. I wasn't particularly fast on this 75k, by the way. It took me 10h23, including the 30 minutes interruption in the middle.

After the last 3 series of tests, the research team handed each of us some nice finisher awards: a commemorative tee-shirt, a laptop bag from the Canadian Society for Exercise Physiology (a sponsor), and a $100 Forerunners gift card (a sponsor as well).

By the time I got home, it was too late to join the party at the Capilano Night run, so my girlfriend and I ended up having to eat all those lemon-meringue tarts she made. Sorry!

Thanks to Jamie and his colleagues, thanks to David Crerar for blogging about the study, and many thanks to Karl for the encouragements and the motivation (and the car ride back to the Skytrain).

The Club Fat Ass should maybe have a standing offer to supply research subjects to local universities. In particular when it comes to long term studies over several years, as CFA has a stable core of runners that stick around over time.