iOS Early Access Open

Health scores that are actually about you.

Laso learns what's normal for your body and tells you what to do about it. Recovery, strain, sleep, stress, illness risk. All from the wearable you already own.

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100% on-device 50+ devices supported No account required

Every morning, five numbers that actually mean something.

Each one is compared to your own history. Not an age group average, not a generic benchmark. Your data, your baseline.

84

Recovery

Above your baseline

7h 42m

Sleep

96% of your need

8.4

Strain

Target: 8–12

Low

Stress

Below your normal

Clear

Health Risks

No warnings

Sample daily brief. All values based on your personal data.

Why most health apps get it wrong.

They compare you to a population average. So someone with a naturally low HRV gets told they're "below average" every single day, even when they're feeling great. Laso compares you to you.

Typical health app

Your HRV 42 ms
Population avg: 55 ms Below Average

"Try meditation and reduce stress."

Laso

Your HRV 42 ms
Your baseline: 38 ms +10% Above Your Normal

"Recovery is high. Good day to push it. Aim for strain 12-16."

Same person. Same number. One app says you're behind. The other knows this is actually a good week for you.

It tells you what to do, not just what happened.

Here's what a morning with Laso actually looks like.

"Recovery 84. Good day to go hard."

Your HRV is up 14% from where it usually sits. Laso sets your strain target to 12-16. Go run, lift, whatever you want.

"You're 45 min short on sleep. Bed by 10:30 tonight."

Laso figured out you need 7h 50m, not the usual "8 hours everyone says." Go to bed 20 min earlier for 3 nights and you're caught up.

"Your HRV has been dropping for 3 days. Take it easy."

Down 15% from your normal. That usually means you're overdoing it. Keep strain under 8 today, walk or stretch, and check back tomorrow.

"Heads up. You might be getting sick."

Resting HR is up 6 bpm, HRV is dropping, and your sleep quality tanked. Laso has seen this pattern before in your data. Get extra sleep tonight and skip the workout tomorrow.

None of this is generic. Every line comes from your own data and your own trends.

Your Apple Watch already collects the data. Laso actually does something with it.

You are the baseline

Laso builds a 30-day picture of your body. When something changes, it's compared to where you normally are. Not where a 30-year-old male is supposed to be.

It connects the dots

Most apps show you 86 metrics and leave you to figure out what they mean. Laso runs causal analysis across all of them and tells you which ones are actually affecting your recovery and sleep.

Nothing leaves your phone

All the analysis happens on your iPhone. No cloud. No account. No one sees your health data. WHOOP and Oura upload everything to their servers. Laso doesn't.

Vitality Age

Your biological age,
updated daily.

Laso looks at 9 things — VO2 Max, HRV, resting heart rate, sleep quality, walking speed, and more — and computes how old your body actually is. No blood test. No lab visit. Just open the app.

Updates every day so you can see if what you're doing is working

Shows you the 2-3 things that would move it the most

90-day trend so you're looking at the big picture, not daily noise

27 vitality age 3 years younger

Recovery, strain, sleep, and illness prediction. One app.

Train with precision

  • Strain score (0-21) with a daily target based on how recovered you are
  • What-if simulation: see what a 10K run would do to tomorrow's recovery
  • Catches overtraining before you feel it
  • Tracks which workouts actually help vs. which ones just wreck you

Sleep with purpose

  • Figures out how much sleep you actually need (it's probably not 8 hours)
  • Tracks sleep debt and tells you how to pay it off
  • Suggests bedtime based on your patterns
  • Shows how your sleep actually affects your next-day performance

Catch problems early

  • Illness prediction 2-3 days before you feel anything
  • Watches for fatigue, burnout, overtraining, insomnia, immune dips
  • Picks up slow changes you wouldn't notice yourself
  • HRV-based stress score with guided breathwork when it's high

Cycle Tracking

4-phase model with phase-specific training guidance

Journal

Log behaviors, discover which ones drive your metrics

Weekly Reviews

Trends, PRs, streaks, and year-over-year comparisons

86 Metrics

Heart, sleep, activity, body, respiratory, mobility, and more

Compatible with Apple Watch, Oura, Garmin, WHOOP, and 30+ more devices.

If it syncs to Apple Health, Laso can read and analyze it. No extra apps. No manual setup.

Smartwatches & Sports Watches

Apple Watch Garmin Fitbit Samsung Galaxy Polar COROS Suunto Google Pixel Watch Huawei Watch Amazfit Xiaomi Smart Band Wahoo TicWatch Fossil Casio G-Shock TAG Heuer Noise boAt Fire-Boltt

Smart Rings

Oura Ring Ultrahuman Ring Air RingConn Circular Ring WHOOP

Health & Fitness Devices

Withings Omron Renpho Dexcom Freestyle Libre Eight Sleep Biostrap Myzone Peloton

Plus iPhone built-in sensors for steps, distance, and activity tracking. No wearable required.

Try it free for 7 days.

You already have the wearable. Laso does the rest. No credit card needed.

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Say Hello Follow Updates

Questions you might have.

What is a recovery score and how does Laso calculate it?
It's a number from 0 to 100 that tells you how ready your body is today. Laso calculates it from your HRV, resting heart rate, sleep quality, sleep duration, respiratory rate, and how hard you've been training. The important part: it's based on your own baseline, not a population average. So if your HRV is naturally 42ms, Laso doesn't tell you you're "below average" like other apps do. It tells you whether 42 is good or bad for you specifically.
How does strain tracking work?
Laso calculates a strain score from 0 to 21 based on heart rate zone distribution throughout the day. It sets a personalized daily strain target based on your current recovery level: higher recovery means you can push harder, lower recovery means you should hold back. The app also includes what-if simulation so you can preview how a planned workout would affect your recovery the next day.
How does illness prediction work?
Laso monitors HRV, resting heart rate, sleep patterns, respiratory rate, body temperature, and activity levels simultaneously. When several of these metrics deviate from your personal baselines in a pattern consistent with immune system activation, Laso flags a potential illness signal 2 to 3 days before symptoms appear. It also tracks 6 predictive health signals: fatigue, burnout, overtraining, insomnia risk, immune dip, and inactivity patterns.
What is Vitality Age?
Vitality Age is Laso's biological age metric, computed daily from 9 key health indicators: VO2 Max, HRV, resting heart rate, sleep efficiency, deep sleep percentage, walking speed, daily steps, exercise minutes, and body composition. Unlike lab-based biological age tests, Vitality Age updates every day from your wearable data. It shows whether you're aging faster or slower than your chronological age, tracks your 90-day trend, and identifies which 2–3 metrics to focus on.
What devices are compatible with Laso?
Laso works with over 50 devices that sync to Apple Health, including Apple Watch, Oura Ring, Garmin, WHOOP, Fitbit, Polar, Samsung Galaxy Watch, COROS, Suunto, Withings, Ultrahuman Ring Air, Dexcom, Eight Sleep, Peloton, and more. If your device writes data to Apple Health, Laso can read and analyze it. iPhone built-in sensors for steps, distance, and activity tracking work without any wearable.
Is my health data private?
Yes. Every analysis in Laso runs entirely on your iPhone. No health data is ever sent to a server. All stored data is AES-256 encrypted with keys in the Secure Enclave. You don't need an account to use the app. No one sees your health data but you.
How is Laso different from WHOOP or Oura?
Three things. First, Laso compares you to yourself, not to population averages. Your 30-day history is the benchmark, so the scores actually mean something. Second, it works with whatever wearable you already have. No buying a WHOOP band for $30/month. Third, everything runs on your phone. WHOOP and Oura upload your data to their servers. Laso doesn't send anything anywhere.