Test a habit on yourself.
Sauna, a cold plunge, an earlier bedtime. Studies tell you what happens on average. A few weeks of your own data tell you what happens to you.
People respond differently. Your data can show how you do.
Most wellness habits are studied in groups, and results are reported as averages. Averages hide a lot of variation between people, though some of it is measurement noise or not sticking to the plan.
If you already wear an Apple Watch or another wearable, you're collecting the data to find out. The trick is to change one thing at a time, stick with it, and give it two to four weeks.
- Low-intensity endurance training: average effects and how much results varied (meta-analysis of 50 studies): Nuuttila et al., Scand J Med Sci Sports, 2026
Plan a 2–4 week test on yourself.
Pick one habit, change nothing else, and give it long enough to show up in your data.
Your plan shows up here: what to do, for how long, and what to watch.
- Do
- For
- Dates
- Watch
- Keep everything else as steady as you can: bedtime, caffeine, training.
- Mark each day you did the habit, so missed days don't blur the result.
- Look at the trend at the end, not day to day. Single nights are noisy.
Popular habits to test
Each protocol page explains the habit, what research looks at, and how to try it.
Sauna 3× a week
Three relaxed sessions a week, then check what moved in your sleep and HRV.
Tracked by Metrya Morning cold plunge
A short, cold start to the day. See whether it changes your energy and HRV.
Tracked by Metrya Test one supplement at a time
Add one supplement, keep everything else steady, and compare taken vs skipped days.
Tracked by Metrya Metrya
Your whole health record on your iPhone: sleep, training, food, water, supplements and context, with an AI advisor that reads all of it.
- Log a habit: cold plunge, sauna, red light, caffeine cut-off, earlier bedtime
- See how sleep, HRV, recovery and energy change over 2–4 weeks
- Nutrition by text, photo or barcode, plus water and caffeine
- Stack: your supplements, with taken vs skipped days
- AI advisor that reads your whole record, on-device or with your own key
- No account. Your data stays on your device.
iPhone app. Runs on your device, no account.