Four months from now, I'm supposed to run 42.2 kilometres in five hours or less, at the BYD Singapore Marathon. That part is simple to explain to anyone. What's harder to explain — including to myself, some mornings — is why I'm building an entire public project around a goal that most people would just quietly attempt and quietly finish or not.
Here's the plain version. I've run four half marathons over the years, and for about seven years I've been tinkering with wearables and biohacking my own training and health data. What I haven't done is follow a plan that a physiologist actually reviewed, or train under anything close to structured supervision — this is by far the most rigorous training block I've attempted, and I still wrote the first draft of it myself, alone. I am not an exercise scientist, a doctor, or anyone with standing to tell another person how to train. What I do have is a stubborn question that wouldn't leave me alone: does training for a marathon actually make you healthier, or does it just make you a person who can run a marathon? Those might be the same thing. They might not be.
The question is the point, not the medal
A marathon has a finish line. You either cross it under five hours or you don't, and the result is unambiguous, timestamped, public. Health has no such line. VO₂ max isn't graded pass/fail. Neither is resting heart rate, body composition, or whatever a blood panel says about glucose control. A person can train seriously for four months and come out fitter in some ways, worse off in others, and unchanged in most. All three of those are real, useful, publishable outcomes — which is exactly why most fitness content doesn't report them. It's easier to sell a story with one direction.
I don't want to sell a direction. I want to run the experiment and publish what happens, including the version where a number goes the wrong way, or nothing interesting happens to it at all.
Why a marathon, specifically
Partly because a marathon forces a real training load — you cannot fake your way to 42.2 km on race adrenaline alone, the way you sometimes can for a 10K. Partly because four months is long enough for a body to visibly adapt (or complain) without becoming an open-ended, never-resolving project. And partly, if I'm being straight about it, because I wanted a deadline with consequences I couldn't quietly ignore. A vague new year's resolution to "get healthier" survives about as long as most vague resolutions do. A dated race number does not.
What I'm not claiming
I'm one person. Whatever happens to my VO₂ max, my weight, or my resting heart rate over the next four months will not prove anything about marathon training in general — it'll be a single, heavily confounded data point, run by someone who also changed his sleep, his stress, and his diet at the same time, because that's what training for a marathon does to a life. The site will try hard not to blur that line. When something changes, I'll say what I think might have caused it and what else could plausibly explain it. When I don't know, I'll say that instead of picking the more interesting-sounding answer.
What's coming
Training started Monday, 10 August. Before that, I wrote a training plan, argued with an early draft of it, and brought in Dr. Varun Reddy — a sports-medicine and research collaborator — to keep the science side accurate, which I'll get into in the next entry. Baseline health measurements are being scheduled; none exist publicly yet, and I'd rather show you a plainly labeled "awaiting data" page than invent a number to make this entry feel more complete.
The Experiment page lays out exactly what's being measured, how, and on what schedule, if you want the methodology before the story. Otherwise, the next entry is about the plan itself, and about how it changed before I'd even started it.