Six months ago, I decided to run an experiment on myself. I would track every quantifiable aspect of my health that technology permitted, and see what the data told me that I didn't already know. By the end of the first month, I was wearing an Oura Ring, a continuous glucose monitor, a Withings scale that measured eight body composition metrics, and running my sleep data through a secondary app. I had a spreadsheet.
By month four, I had dropped three of the four devices. By month six, I had more clarity about my health than I had at any previous point in my life — and I had achieved it with dramatically less data than I started with.
Here is what I learned.
"More data does not produce more insight. At some threshold, it produces paralysis dressed up as optimisation."
The CGM Was Fascinating and Mostly Useless
A continuous glucose monitor (CGM) measures your blood sugar every few minutes and sends the data to your phone. Designed for diabetics and people with insulin resistance, they have been adopted by a growing cohort of healthy people interested in metabolic optimisation.
I wore one for eight weeks. The data was genuinely interesting. I could see in real time how different foods, exercise timings, and stress events affected my glucose. A stressful meeting spiked my blood sugar as much as a croissant. A 20-minute walk after lunch flattened my post-meal response significantly.
But here's what I noticed: after about three weeks, the data stopped generating new insights. I had learned what I was going to learn. My glucose response to food is fairly typical. I don't have insulin resistance. My worst spikes came from white rice eaten alone, which is not a revelation that required £150 and eight weeks of staring at a graph.
For people without metabolic issues, CGM use shows real behavioural changes in the first 2–4 weeks, then rapidly diminishing returns. The data is most valuable as a one-time educational experience rather than an ongoing monitoring tool for the majority of users.
Sleep Tracking Was the Most Valuable — With Caveats
The Oura Ring's sleep tracking was the one device I kept. Not because I trust its deep sleep and REM stage estimates — the scientific validity of wrist or finger-based sleep staging is genuinely contested — but because the readiness score gave me something useful: a daily number that correlated, over time, with how I actually felt and performed.
The insight wasn't the score itself. It was what the score's variation revealed about which variables actually affected my sleep quality. Alcohol at any quantity, even one drink, visibly degraded my readiness the following morning. Room temperature mattered significantly. The time I stopped looking at screens mattered less than I expected — but the time I stopped working mattered more.
What Actually Moved the Needle
After six months of tracking, the interventions that genuinely improved my measurable health markers were not sophisticated. They were:
- Consistent sleep and wake times — more impactful than any supplement, device, or optimisation protocol
- Zone 2 cardio three times per week — low-intensity sustained effort, which improved my resting heart rate by 8 BPM over the period
- Eliminating alcohol on weeknights — the single highest-leverage change I made, with visible effects on sleep quality, energy, and cognitive clarity
- Eating the same breakfast every day — not because any particular breakfast is optimal, but because removing the decision reduced one source of cognitive overhead and kept my morning glucose stable
"The health data revolution has given us extraordinary tools to confirm, in expensive detail, what we already knew."
My Verdict on Each Device
Kept: Oura Ring
Sleep readiness score useful as a daily calibration signal. Best for people who want one number rather than a dashboard.
Dropped: CGM
Valuable as a one-time educational tool. Not worth ongoing cost or cognitive overhead for metabolically healthy users.
Dropped: 8-metric smart scale
Body composition estimates from consumer scales are not accurate enough to act on. Weight trend alone is sufficient for most people.
Kept: Simple step count
Daily movement is the most underrated health variable. A basic step goal (8,000–10,000) remains one of the highest ROI health behaviours.
The Honest Takeaway
The quantified self movement is valuable precisely to the extent that it produces behaviour change, and counterproductive to the extent that it substitutes measurement for action. The people I know who are genuinely healthiest are not the heaviest trackers. They are the people who found three or four things that worked for them and did them consistently — usually things they identified through introspection and experimentation rather than a dashboard.
Technology can accelerate that discovery process. But no device eliminates the work of actually changing behaviour. And no amount of data quality compensates for the fact that most of us already know what we should be doing — sleeping more, moving more, eating less ultra-processed food — and are choosing not to do it.
The most useful thing I bought in six months of health tracking was a cheap alarm clock, so I could leave my phone in another room at night.