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Finally, understand your body.

Every morning, one clear answer about what your body needs today. Built from your data. Not an age group average.

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100% on-device Apple Health compatible No account required
27 vitality age 3 years younger

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.

Sprinter in starting blocks on track, close-up detail

Dozens of Apple Health signals from the device on your wrist. One app that makes sense of them.

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 dump dozens of Apple Health signals on you and leave you to figure them out. Laso runs causal analysis across them and tells you which ones are actually affecting your recovery and sleep.

"Your sleep debt rose four nights in a row because late workouts pushed HRV down."

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.

The wearable stays.

Apple Watch, Oura, Garmin, WHOOP, or any device that syncs to Apple Health. No new ring. No extra strap. No monthly hardware fee.

See compatible devices →
Person training with weights in a gym, representing an active fitness lifestyle

Try it free for 7 days.

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

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Free 7-day trial. iPhone & Apple Watch. iOS 17+.

Understand the numbers behind your score.

Heart Rate Variability → VO2 Max → Sleep Debt → Biological Age →

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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 early wellness pattern detection 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 recognizable pattern, Laso flags body stress signals early so you can adjust your routine. It also tracks 6 wellness signals: fatigue, burnout, overtraining, insomnia risk, recovery dips, and inactivity patterns.
What is Vitality Age?
Vitality Age is Laso's fitness age estimate, 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 tests, Vitality Age updates every day from your wearable data. It shows how your body is trending relative to your chronological age, tracks your 90-day trend, and identifies which 2 to 3 metrics to focus on.
What devices are compatible with Laso?
Laso reads Apple Health on iPhone, so Apple Watch works natively and many companion apps can feed data in once Apple Health sharing is enabled. Publicly mapped sources include Garmin, Oura Ring, WHOOP, Polar, COROS, Withings, Dexcom, Ultrahuman Ring Air, RingConn, Circular Ring, Renpho, Omron, Biostrap, Myzone, Peloton, and more. Laso shows the exact metrics after the source writes samples. iPhone built-in sensors for steps, distance, and activity also work without a 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.