Solo g10k and arbitrary units

21 Dec 2025

Time passes, things change. I’ve been conscious of this recently as I celebrated a not-big birthday.

I realised in the run-up to this anniversary that my age in years was close to my smartwatch-predicted 10km run time in minutes. So I set out to prove to myself that I’m still young and relevant. By attempting this timed run challenge I suppose I was aiming at one minute per 10km per year, or something. I made it with a moderately hard effort (fist pump), although it wouldn’t have qualified for a true g10k because I used the prediction-fostering smartwatch to pace myself around. I might revisit this challenge in years to come. Given my choice of units, I get an extra 6 seconds per kilometre for each year.

I got to thinking of other metrics whose values - in their commonly-chosen units - might coincidentally intersect at different times of life. Right now, my age (years), 10km run time (minutes) and resting heart rate (Hz) are all close. I wonder if I’ll be running a 10km in an hour if I get to 60? Max heart rate is supposedly approximately equal to 220-age, so I just need to wait until I’m 110 years old for that one. Body mass? Well I’ve always been heavier in kilograms than my age in years, but that might change in about 20 years if I keep my scrawny body shape into my 70s.

Tags: geeky, meta