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Halden

AI fitness coaching · early access

Know what to do tomorrow. And why.

Every night, Halden reads your sleep, your HRV, and what you lifted, down to the set, then builds tomorrow's session around it. Harder when you're recovered, lighter when you're not, explained in plain language with citations.

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No spam. One email when your invite is ready, and you can opt out anytime.

iPhone + iPad + web dashboard · works with anything that writes to Apple Health

Illustrative product UI

01How it works

A closed loop, not a static program.

Most apps collect data and stop there. Here, the data has a job: deciding what tomorrow looks like.

  1. Connect & check in

    Apple Health brings sleep, HRV, and resting heart rate. You add soreness and fatigue in ten seconds.

  2. Readiness is scored

    A transparent 0–100 score from your last 14 days. You can see every subscore that feeds it, so nothing hides in a black box.

  3. Tomorrow's plan adapts

    Harder when you're recovered, lighter when you're not, and built around whatever you've already got booked. Every plan comes with a plain-language rationale and evidence citations.

  4. You log. It learns.

    Every set, RPE, and pain flag you log tonight measurably changes what tomorrow asks of you.

The loop closes every night. Your plan is regenerated, not reheated.

02Who it's for

One data spine. Two ways to use it.

For athletes & lifters

Stop guessing on the days that matter.

You already wear the watch and log the food. Halden turns that data into tomorrow's session: harder when you're recovered, lighter when you're not.

How athletes use it

For coaches

See between the sessions.

Readiness, adherence, set-level logs, and nutrition for every client, scoped to exactly what they chose to share, with every view audited. The AI handles daily adjustments; you stay the authority.

How coaches use it

03Plan your week

Every workout, on the day it happens.

A calendar that lays your whole week out on real dates: your coach's sessions, your AI plan, and the workouts you added yourself, side by side. Today rolls all of it into one list, and the AI coach answers around the same schedule.

  • See planned workouts on real dates from every source at once: coach assignments, AI-plan days, and your own sessions.
  • Stack more than one workout on a day when you need to, like a coach session plus your own accessory or conditioning work.
  • Your nightly AI plan works around what's already booked. It won't double-book a full day, and it pairs a hard session with recovery instead of piling on.
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04Connected intelligence

Recovery, nutrition, and training finally talk to each other.

Each signal is useful on its own. Together they answer the question you're really asking: is this working?

Health & recovery

A transparent 0–100 readiness score from sleep, HRV and resting-heart-rate trends, soreness, and fatigue. Every subscore is visible, with 7-day sparklines.

Nutrition

Calories, macros, water, and caffeine imported from the food logger you already use, plus a personalized protein target that feeds into your plan.

Strength training

Live set-level logging, from reps and load to RPE/RIR and pain flags, that feeds straight into tomorrow's session. Offline-safe, and editable later on the web.

05Performance

Progress you can measure.

Tonnage, estimated 1RM trends, completed-set ratio, training-load ratio, VO2 max: all computed from what you logged, not what the template hoped.

Explore performance analytics

Weekly tonnage

24,180kg

Bench e1RM

+4.2% this block

Completed sets

92%

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06Apple Health

One connection. Every device you own.

Halden reads Apple Health, so any watch, ring, strap, or food app that writes to it just works. Sleep stages, HRV, VO2 max, workouts from other apps, daily activity, nutrition. You approve each category separately, and you can turn any of them off.

How the Apple Health connection works

07AI next-day planning

An AI coach that shows its receipts.

Every plan comes with a plain-language rationale and citations from a real strength & conditioning reference corpus. And before any AI writes a word, five deterministic safety gates run first: hard-coded rules the model can't be talked out of.

  • Emergency symptoms. Chest pain, fainting, or similar language stops the workout and points to emergency care. Always.

  • Pain & injury. A pain flag blocks progression on that movement pattern and swaps in technique and mobility work.

  • Eating-disorder risk. Restrictive or compensatory language is never echoed back. The app answers with support and a referral instead.

  • Supplements. Education only. The app never doses, prescribes, or sells.

  • Readiness downshift. When recovery data says back off, volume and intensity come down. There's no motivational override.

Safety decisions are deterministic code, not model output. The AI is never asked to judge whether chest pain matters.

How the AI coaching worksPrivacy & data control

What a generated plan looks like

TomorrowLower body · readiness-adjusted

  • Warm-upHip openers + ramp-up · 8 min
  • MainSquat 3×5 @ RPE 7 · RDL 3×8 · Split squat 2×10
  • CooldownBreathing + quad stretch · 5 min

Volume −15% · short sleep two nights running

Squat load held · HRV back at baseline

Why this plan · 3 citations

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08At a glance

What is Halden?

Halden is an AI fitness coaching app that turns your recovery data, check-ins, and set-level workout logs into a 0–100 readiness score and an adaptive next-day training plan, explained in plain language with evidence citations. It's built for athletes and lifters, with a coach marketplace and portal alongside.

Category
AI fitness coaching and adaptive workout planning, with workout tracking, recovery and readiness scoring, performance analytics, and coach tooling.
Platforms
iPhone and iPad app plus a web dashboard. Android (via Health Connect) is on the roadmap, not available yet.
Availability
Invite-only early access through the waitlist. Not on the App Store yet; there is no public download today.
Works with
Any app or device that writes to Apple Health: watches, rings, straps, and food loggers included. No per-brand integration list.
Data it uses
Sleep, HRV, and resting-heart-rate trends; soreness and fatigue check-ins; set-level workout logs (reps, load, RPE/RIR, pain flags); and imported nutrition (calories, macros, water, caffeine).
Who it's for
Athletes and lifters who train seriously, and coaches who want between-session client visibility on the client's terms.
Price
Early access is free. Final pricing isn't set yet; early-access users hear first.
What it doesn't do
No medical advice or diagnosis, no calorie targets, no in-app coach–client messaging, and no payments or booking.

Halden provides general fitness guidance, not medical advice.

Train on evidence, not vibes.

Join the early-access list and be first in when invites open, as an athlete or as a coach.

iPhone, iPad + web today, via early access. Android coming. Not yet on the App Store.

I am joining as

No spam. One email when your invite is ready, and you can opt out anytime.