Last Saturday I ran 75 kilometers (46.6 miles) at an elevation of 6,500 feet, about 40 miles north of the equator. When I finished after 8 hours, the temperature was a balmy 92 degrees Fahrenheit (32 C). I wiped my hand across my forehead and could see large salt crystals on my fingertips.
I usually run at sea level and in temperatures maxing out around 80 F. This was uncharted territory in just about every way.
But it was familiar in one sense. In training, I didn’t use any instrumentation - no GPS, no heart rate monitor, and no watch. During long runs, the objective was to run at “infinite-mile pace,” a pace that felt easy enough to continue indefinitely. The actual pace wasn’t important - how it felt was.
So while I didn’t have practice running in the conditions I encountered, I did have practice at assessing, on the fly, how much I was exerting myself and dialing that into a level that was going to be sustainable for 8 hours.
Every run is set against a myriad backdrop of variables that affect performance. Temperature, elevation, the running surface, muscles' initial glycogen loads, sleep deficit, distance run the previous day, week, even year.
Bundle all these things together and you get the equivalent of a headwind or tailwind on a plane. In many cases you want to measure groundspeed. The Olympics and world record attempts, for example. The figurative headwind is an input; groundspeed is the output.
Last Saturday, though, groundspeed was an input. It was more important to measure airspeed - how hard it was to move given the figurative headwind. Groundspeed was one more thing to adjust in order to make sure that everything was working well and would continue to do so for a long time.
Do What You Feel
You can do things without instrumentation provided that you’re not akratic about what you’re doing. If you’re not currently someone who enjoys running, or writing, you can’t just trust yourself to “run as you feel” or “do as much you feel” - you’ll constantly be overestimating the figurative headwind by coming up with excuses: “it’s really muggy today, better cut this short” or “I wrote a lot yesterday, and I can’t think in this cafe, it’s too noisy”.
If you’re not at the point where you can just do exactly what you feel and be satisfied with it, instrumentation can help get you there. But eventually the training wheels have to come off, and the sooner the better - it’s an unhappy existence to always rely on the instrumentation as a source of satisfaction.
With practice, we can all become kids again.