r/QuantifiedSelf

Post your apps here, and please support people bringing unique ideas to this space.

Free tool. For all the coffee lovers. ❤️

Ever wondered how much caffeine is actually in your coffee? ☕

I built a tool that estimates it based on how you brew
(not generic averages)

Also shows a confidence range which gets tighter as you add details 📊

Would love your feedback! 🙌

Hi all. The question speaks for itself. I always have issues when I try and log qualitative data, and the only one I've ever managed to crack is sleep rating on a scale of one to ten because I set up an Apple shortcut whenever I wake up.

I've been unable to figure out anything else that I can consistently do, and I was curious to know how everyone else maintains the habit of data entry.

I’ve been relying on Inbody scans to track my progress, but I’m starting to question if it’s worth the cost long term. I don’t mind paying for accuracy, but realistically I just need something that helps me see whether I’m moving in the right direction (fat loss, muscle gain, etc.), not necessarily lab level precision.

I’ve looked into smart scales and other at-home options, but it’s hard to tell if they're reliable or not. And at this point I’m debating whether I should just stick with Inbody scans and just go less often, OR try my luck with smart scales and just track trends even though they're not exactly accurate.

Hoping someone with experience with smart scales weigh in, cause I'd really prefer a more convenient and affordable alternative.

Hey fellow data nerds! I would love to know what your personal processes for your entire process from data capture all the way through to visualization.

I personally took a data analytics boot camp like 5 years ago so I know and appreciate good data visualization. However I ended up going down a different career path so I have actually lost most of the knowledge. My current process now is very AI heavy. I literally screenshot logs from various apps, as well as export Apple Health and have claude crunch it. This is okay but the graphs made by claude are very basic.

Most of the "I tried X supplement for 30 days" posts I read (on Reddit generally) are underpowered to the point of being noise:

1. No washout before starting.

2. No blinding (obviously hard for n=1 but there are tricks).

3. No pre-specified outcome metric.

4. Confounders ignored (sleep, training load, alcohol).

5. Subjective measures logged retrospectively.

For QS folks actually trying to do n=1 right, what's your setup? Some things I've been trying:

1. 4-week ABAB design, 1-week washout between phases.

2. Pre-registered (with a friend) outcome metric before starting.

3. Third-party relabel of capsules so I don't know which phase I'm in (imperfect but better than nothing).

4. Auto-pulled objective metrics (HRV, sleep, resting HR, workout performance) instead of self-rated.

Interested in how other people handle pre-specification and blinding specifically. Has anyone built or found tooling that enforces the protocol rather than just logs?

Hey everyone!

I'm a master's student at TU Delft ( Studying MSc in Design for Interaction), researching how Muse or other EEG wearables users interpret and reflect on their EEG data, specifically that moment when your session score doesn't quite match how you actually felt during or after the session.

I'd love to hear about your experience, what you do with your scores, what frustrates you, and what would make the data feel more meaningful.

The survey takes about 5 minutes and is completely anonymous.

Survey link -> Link

I'll be happy to share the findings with the community once the research is complete or dm me if you want to know more. Thank you so much! 🙏

For the last several months I've been self-tracking decision fatigue. Question I was trying to answer: can you quantify "mental tiredness" in real time using passive signals from an iPhone, accurately enough to be useful for decision timing?

The model I landed on uses 4 weighted signals combined into a 0–100 score:

1. Decision load (50%) — self-logged decisions, weighted by cognitive cost (trivial/medium/heavy)

2. Time-of-day (20%) — adjusted circadian curve, anchored to personal wake time, with a post-lunch dip

3. Motion / restlessness (15%) — CoreMotion step cadence variance as a fidget proxy (fidgeting correlates with depletion in the lit)

4. App switching (15%) — context switch count as a proxy for scattered attention

Calibration: first 3–5 days builds a personal baseline so the score is relative to YOU, not absolute. Without this the score is meaningless — some people peak at 11am, some at 4pm.

What surprised me:

• Motion signal is noisier than expected — had to add EMA smoothing with a 20-min window

• Decision weighting matters more than decision count — 1 heavy decision ≠ 10 trivial ones

• The afternoon slump is real and shows up cleanly in the data around 1:30–3pm for most testers

Things I haven't figured out yet:

• HRV integration (would probably replace motion as the physiological signal)

• Sleep debt carryover — currently ignored

• Caffeine compensation

Anyone else working on cognitive load / decision fatigue measurement? Would love to compare notes on signal selection.

(App link in first comment per sub rules.)

I've been tracking everything for years — workouts on Hevy, sleep on Apple Health, weight on RENPHO, HRV through my Apple Watch. But none of these apps talk to each other.

Recently started manually exporting and connecting the data myself. First thing I found: every time I train 5-6 days a week, my deep sleep drops ~25 minutes per night. My progress has been stalled for months and this was the reason — none of my apps ever connected these dots for me.

I want an app that does this automatically. It pulls everything together through Apple Health and gives you one clear daily instruction based on your actual data. Not a dashboard of numbers — more like a coach that says:

"You've trained hard 3 days in a row and your HRV dropped 18%. Take a rest day today."

or

"Your sleep has been strong and HRV is up. Your body is ready — push hard today."

Would love to connect with people in this community who:

• Manually piece together data across multiple apps
• Have spotted patterns in their own data that none of their apps flagged
• Want coach-style daily recommendations rather than just raw numbers

Not selling anything. Just want to talk to people who feel this problem. What patterns have you found in your own data that surprised you?

This is not a promotion. I have not built the app.

Before the era of AI slop took over this sub, it was a lovely corner of the internet, but I can tell a significant amount of people un-subbed to avoid seeing the constant app advertisements.

I would like to open the floor to the community for suggestions of weekly mega-thread ideas or other community events that we could come together to try to bring some life back into r/QuantifiedSelf

Some thoughts, in no particular order, a monthly book thread, AMA from health and statistics professionals, protocol discussion.

What do you guys think?

Hi all,

Would like to get some opinions on what device is a better choice for my needs. I’m struggling a bit with feeling tired + low energy during the day, so I’d like to start tracking my sleep quality and perhaps other health metrics.

I’ve watched some of the comparison videos but still a bit stuck with my choice.

I’m not price sensitive but I’m not a fan of the monthly subscription model.

Is there a big difference between these two devices for accurate sleep tracking?

TIA

Post your apps here, and please support people bringing unique ideas to this space.

I’ve been thinking about how to measure changes in relationship behavior over time, especially when working on attachment patterns.

After trying some structured exercises from Personal Development School, I noticed fewer immediate reactions in certain situations, which suggests some change, but it’s hard to quantify without clear metrics, so what indicators would you track to objectively measure progress in attachment-related behavior?

Hi everyone,

I’ve spent the last few weeks falling down the rabbit hole of health trackers, and honestly? I’m exhausted. It feels like every time I find a device with decent sensors, it comes with a mandatory cloud account or a "premium" subscription just to see my own data.

I’m looking for the "Privacy Unicorn" for two specific things: high-quality sleep tracking and skin temperature sensing (I need this for basal body temp/cycle tracking).

My needs:

• 100% Local storage: I want my data to stay on my phone, period. I can use Gadgetbridge and I’m looking for something that plays nice with it (or any FOSS alternative).
• No Screen (if possible): I just want a "set it and forget it" vibe for day and night. I don't need another glowing rectangle in my life.
• No Subscription: I refuse to rent my own heartbeat.

I’ve looked into the Oura (too much cloud), Whoop (subscription hell), and Tempdrop (great for cycle, but limited for sleep/local). I'm hearing rumors about the Garmin Cirqa and the Amazfit Helio Strap, but has anyone actually managed to get something like this running in a "de-googled" or air-gapped way?

Is there a hidden gem I’m missing? Or maybe a way to "lobotomize" a mainstream tracker so it only talks to my phone and never to the mothership?

Any leads would be life-saving. Thanks!

I'm having Garmin Index S2 and I feel without DEXA calibration is pretty dumb and somehow off on fat and muscle. Originally I was looking on Withings BodyScan2 which should be out Q2 26 they say but meanwhile scouting if it's something great for home. Found Tanita, their top line is using two BIA frequencies and have some muscle scores (marketing?). Ideally something I can feed into Garmin Ecosystem and eventually Google Fit/Apple Health.

I think something with 8 electrodes for hands and feet would be great, range up to $1k should be good.

Goal is to spot recomposition granularity not just see water oscilation in the body and water in the muscle. Tanita says they can distinguish two or three types of muscles.

Are there any great candidates out there I might miss? which body scale you have and why? which you're eyeballing for an upgrade if so?