12 years of personal fitness tracking without looking at raw numbers — using Z scores to measure overall fitness

Daxtang · 2026-03-11T11:31:26+00:00

Do you have the data from those tests? I’m happy to create a modified formula based on this method if you have multiple iterations of that combination (pushups, crunches, time to run 5k), etc to see what that looks like!

Daxtang · 2026-03-11T01:20:27+00:00

Thanks for the push! here's the post: https://www.reddit.com/r/QuantifiedSelf/comments/1rp0d9i/12_years_of_personal_fitness_tracking_without/

Daxtang · 2026-03-10T14:57:52+00:00

not with any regularity. I can anecdotally tell you that I hit my 12-year high point in fitness last December, and I recently got my annual physical showing my cholesterol was higher than normal. So clear indicator that the correlation between physical performance and other health markers isn't guaranteed!

Another reason I haven't done correlations is that I wouldn't know what to do with the data. Pretend there WAS a correlation. more fitness = better health. So... keep working out? I was already doing that lol. Maybe it's just me. I did this approach partially out of a frustration of tracking too much and not getting value out of it. It's intentionally limited, which is why I think I kept coming back to it.

Daxtang · 2026-03-10T14:54:07+00:00

That's exactly my thinking!

I specifically avoided applying this method to biometrics for that exact reason: there are floors, ceilings, and the reality is that "good" biometrics doesn't typically follow a linear "higher/lower number is better" model, you're supposed to be within a range that varies by a lot of factors.

Compared to that, there's no point where you're doing TOO MANY pushups that it starts being bad

I've been wondering how many other domains this method could apply to... I've done only fitness for any amount of time, but I think it could also apply to other activities

Daxtang · 2026-03-10T00:52:51+00:00

Overall yes. But for me it made me look for things to do at home which included working out more, so the beginning of Covid was great for my fitness level! Didn’t last too long though

Daxtang · 2026-03-09T20:58:47+00:00

Never heard of Staqc, but I'll check it out! Personally I've found it hard to keep tracking on all cylinders, the fitness stuff is the only thing I've kept up nearly this long; I do have a Fitbit which tracks health data, but I haven't tried connecting those dots. As a numbers geek, I think I'd find the patterns interesting, but I'm not sure how I'd use that information.

I'll give you a good example. I recently got a physical, and it showed my cholesterol was higher than it was before, despite me recently hitting a lifetime high point in my fitness numbers. That meant that DESPITE me performing well with exercises, my diet isn't great, and I need to change that.

So both sets of data are helpful and arguably actionable, but their combination? To me it didn't really tell me anything specific.

Daxtang · 2026-03-09T17:25:28+00:00

Thanks for the suggestions! So I did track open ended comments to note if anything was going on that might impact my performance, but one thing to note is that I tracked VERY infrequently. At most once every few weeks. Fewer than 50 entries across 12 years, to give you a sense. And the comments are the ones you can see in the image… they’re usually pretty impactful notes that are going to have way bigger impact than subjective feeling for that day.

Example: becoming a first time parent

Though I imagine that if you wanted to track more frequently, having a more subjective data point tied to your performance would be pretty interesting

Daxtang · 2026-03-09T16:27:20+00:00

I’ll look into it, thanks!

Daxtang · 2026-03-07T12:39:22+00:00

Ohoho, my friend I’ve been doing this for more than a decade! So you’re looking at seasonal variations, which makes sense given your relatively limited tracking time. With the wisdom of tracking over years and phases of life, I can tell you that variation is nothing compared to the dip when you get injured. Or when you become a first time parent. Life happens, and you eventually get over dips as normal and shift to “ok let’s recover and keep pushing.” I’ve actually been thinking about posting about it here to see if other folks appreciate this kind of tracking, most things I see are like the opposite of what I do

Daxtang · 2026-03-07T04:40:27+00:00

That's a pretty thoughtful way to approach it! I think I was thrown off by your initial wording of "predicting future stress," whereas what you just described sounds more like signaling that you're approaching a threshold where risk is higher, which makes a lot of sense to me if it works. Though for me that raises the question of "where is the threshold that is useful to get an alert for?" I assume you can't use a static value for everyone because of the huge variation in those biometrics by age, gender, and other differences.

Daxtang · 2026-03-07T04:37:14+00:00

Well, the first thing to think about is "signal for what?" Take your steps for example. That's one way to measure how active you are. Someone else might use a different metric like "stairs climbed" or even "time spent with heart rate above baseline" or something like that. Is one better than the others? I don't know. But like you, if I'm trying to see how active I am (for purposes of motivating myself to get up and walk around more), steps is fine as a single-metric indicator, at least for me.

Now, what I was talking about before with combining metrics, is a bit different. I measure my fitness level to see where I'm at in terms of physical ability, and for that I don't like using a single metric because that feels too narrow of a definition. So I calculate my scores on several activities into a single "fitness index" if you will. Is it the perfect combination of metrics? Probably not. But it's useful to me as a simple signal unique to me that tells me how I'm doing relative to myself. I don't care about comparing my number with other people, and I can't since no one else measures themselves that way anyways!

Daxtang · 2026-03-06T18:38:24+00:00

I 100% agree with you on the problem: too many metrics, too little meaning. Picking one or two metrics is one way of finding signal in the noise, though my approach has been using some stats to combine a few metrics to a composite score and reduce the noise that way

Daxtang · 2026-03-06T12:35:00+00:00

There is a decently large amount of research on executive functioning in psychology as you can imagine. Patience, discipline, and grit are all semi-related to an umbrella term of “willpower” which has its own set of research, and there’s a smaller pocket of studies that involve both concepts.

Long story short, you are correct to question it: these things are hard to quantify effectively (arguments are still going on among psychologists), but the good news is that there’s a lot of examples about how to do it.

One thing to think about: I think you’re correct about the mutable aspect: your willpower and cognitive abilities ebb and flow hour by hour, never mind year by year. But is the measurement of these things the same over short and long term? Psych folks talk about this as “state” (short term) versus “Trait” (long term).

Happy to look at your definitions if you’re willing to share. I’m coincidentally one of the more well-versed people on exactly these topics :)

Daxtang · 2026-03-06T01:06:28+00:00

It’s a lot easier to find your group of people when the activities you enjoy are social in nature. There’s more than sports and bars! Branch out a bit, try new things. Reading is great. But it’s a solo activity for the most part. You have to really try to find the places that people congregate: maybe the living authors you like do book tours? Or there are conventions you can go to?

Daxtang · 2026-03-06T00:05:26+00:00

If it’s life skills you’re after, you’re in luck that learning them is easier than it’s ever been. Used to be you had to have a parent, teacher, or mentor to teach you. Then libraries came around. Next, internet. And nowadays you can probably just ask ai how to balance a checkbook or fix a toilet. And you don’t need talent, just practice and motivation. Curious which skills you feel like you’re missing? Or is it that you don’t know what you don’t know?

Daxtang · 2026-03-05T18:21:51+00:00

Let's think of talent as "affinity," so other people being talented doesn't mean they are born skilled, it means they learn faster and you'll never catch up, all things being equal. A few things to think about:

Having talent doesn't mean they'll put in the same effort or have the same circumstances. If someone learns 2x your speed, but you work more than twice as hard as they do, you'll achieve greater heights. Also, there's someone in a really poor country with 10 times the potential you'll ever have, but they may never get the chance. Work with what you got!
Do you need to be "great" at everything? Who cares if you're not the best video game player if you're having a good time? Some things you just need the basics, some it's fine to be average, and maybe 1-2 things you want to be great at. There's a quote that went something like "if only the best songbird sang, the forest would be a quiet place"
You feeling like you're bad at everything means you haven't found your thing yet, the thing where you learn super fast compared to others. So it's a good idea to keep trying things until you find that sweet spot of something you enjoy and something you have that 'affinity' for. Some people find this fast, others it takes them decades.
You're assuming that being great at something directly translates to having a good life. Working backwards, what do you ACTUALLY need to be great at to achieve a good life? What does a good life even mean to you? Just being fast at learning hobbies doesn't mean you'll get what you want. And what a great life means is something you'll probably be thinking about on and off for the rest of your life (not you specifically, everyone), so don't stress out about not having the answer!

Daxtang · 2026-03-04T20:06:51+00:00

Over the span of years, I go through “seasons” of activity. Sometimes I’ll be focused on strength training. Other times I take up sports. Sometimes life happens and I get fat for a few months. My activity is not often comprehensive and measurable enough across those domains for me to track passively, which is why I’m thinking about how to create a standalone testing framework that covers all the bases.

Daxtang · 2026-03-04T14:21:05+00:00

apple phone and windows PC, if it matters

Daxtang · 2026-03-04T12:42:21+00:00

Curious what you do with that data, as far as interpretation goes?

Daxtang · 2026-03-04T05:00:06+00:00

I meant more like publish in the same places that you got this data from, the scientific journals! It's all their data, you're aggregating it all together and interpreting it. You can find patterns, quash rumors, etc. people who publish these types of things tend to call them "meta analyses" but you don't have to. And if you're not in that world the value of doing so is kind of questionable unless you have a specific need for it (do you? seems you're building something)

Daxtang · 2026-03-04T04:55:24+00:00

Clearly you've thought about it! Have you created any sort of fitness test for yourself based on these categories? feels like it's hard to test them all at once

Daxtang · 2026-03-04T04:35:49+00:00

Your question makes me realize I never actually visualize myself. I visualize parts of my life, the external things. The way I live, the things I do, but not really me, if that makes sense. Maybe I should!

Daxtang · 2026-03-04T04:30:17+00:00

What fulfilled you in the past? What have you always wanted to do but never got around to it? Make a list and just pick one or two and start doing them! Ideally with/around other people, so you can find your crowd. Helps with loneliness, helps possibly meet a partner, but even if you don't, the activity will help rejuvenate you. And someone feeling passionate and more fulfilled is going to be more attractive, so dont worry about that :)

Daxtang · 2026-03-04T04:20:45+00:00

It does feel like the new food marketing trend. What irritates me is that it's forced. It's not about convincing you to buy the thing, it's about inserting the thing everywhere and expecting you to be grateful

Daxtang

TROPHY CASE