--cd5f01826dc47410 vary: rsc, next-router-state-tree, next-router-prefetch, next-router-segment-prefetch x-nextjs-stale-time: 300 x-nextjs-prerender: 1 x-next-cache-tags: _N_T_/layout,_N_T_/page,_N_T_/,_N_T_/index content-type: text/html; charset=utf-8 BodyAtlas: Strength logger with a muscle-recovery heatmap, now on the App Store
BodyAtlas
A muscle atlas, on iPhone

See where you’re cooked.Train where you’re fresh.

BodyAtlas is a fast strength logger fronted by a per-muscle recovery heatmap. Logged sets deposit fatigue; muscles cool on their own half-life. Open the app, glance at the map, decide what to train.

Platform
iPhone
Sync
iCloud
Pricing
Lifetime; 3 free workouts
Plate 01 · Front
fig. 1.0
Recovery stateT+18h since last session
Cooked
Fatigued
Mid
Cooled
Fresh
The hero screen

Two views of the same body. One honest snapshot of where you stand.

Swipe between front and back. Every muscle group is tappable for a drill-down: which exercise hit it last, when it’ll be fresh again, projected hours to full recovery.

9:41●●● ●●
Last workout18h ago
Fresh groups7 of 12
Heatmap
Fuel
Settings
Front view · post pull day
  • Recovery 0–25%Cooked

    The muscle worked hardest in your last session. Don’t train it today.

  • Recovery 25–50%Recovering

    Still actively repairing. Cardio or accessory work is fine. Heavy compounds, hold off.

  • Recovery 50–75%Mid

    Could push it. Diminishing returns vs. waiting another day.

  • Recovery 75–90%Cooled

    Near baseline. Safe to load.

  • Recovery 90%+Fresh

    Ready to be the focus of today’s session.

Now on Apple Watch

Log a set from your wrist. Live HR straight to Apple Health.

The watch app pairs with your iPhone, runs an HKWorkoutSession so heart rate and active calories stream into Apple Health for the duration of the workout, and stages your exercises as a paged stack so the active one is always one swipe away.

Plate 02 · Wrist
fig. 3.0
rest · 1:24Bench PressSet 3 of 4142bpm188kcal
Live sessionHR · 142 bpm
Paged exercise stack

A vertical TabView shows one exercise at a time. Tap to log a set; weight + reps prefill from your last set.

Live HR + active calories

Streams to Apple Health via HKWorkoutSession for the full session. No second device required.

Survives mid-session disconnects

Logged sets buffer to an on-disk queue on the watch and flush back to the phone when the connection comes back.

What’s in v1

Built for lifters who want the heatmap without the subscription.

  • Per-muscle recovery heatmap

    Front and back anatomical views. Every logged set deposits fatigue weighted per exercise. Muscles cool on their own half-life: large muscles 48–72h, small 24–36h.

  • Two-to-three-tap logger

    Last session's weight and reps pre-fill every new set. Warmup, working, failure flags. 1RM estimate (Epley + Brzycki). PR detection inline.

  • Fuel: daily nutrition logging

    Four meal slots, macro rings, custom foods, day-by-day nav. Writes dietary entries to Apple Health. Targets editor in Settings.

  • Workout templates

    Save any finished session as a reusable routine. Start from a template and weight + reps auto-fill from your last time on each exercise.

  • Weekly schedule + reminders

    Plan your training days, get a local notification at the time you choose, tap it and the right session is staged. Pro feature.

  • Rest timer on Lock Screen + Dynamic Island

    Live Activity countdown follows the rest timer everywhere. Skip or extend without opening the app.

  • HealthKit, both directions

    Writes every workout to Apple Health as a strength session. Reads your last 30 days of strength and cardio on first launch, so the heatmap is populated day one.

  • PR tracking with history

    Per-exercise history view with set-by-set trend, PR markers, simple trendline. No social leaderboards. No streaks. Just your numbers, sorted.

  • iOS-native, on-device, one purchase

    SwiftUI, SF Symbols, Dynamic Type, VoiceOver, Liquid Glass. Same-user iCloud sync via private database. No accounts, no server, no analytics on what you lifted.

The math behind the colors

Honest recovery, modeled.

Every logged set deposits fatigue onto its target muscles, weighted by exercise. Each muscle recovers on an exponential curve with a half-life tuned to its size. The heatmap is just a render of that number.

Fig. 2 · Recovery vs. timer = 1 − e−t / hl
CookedRecoveringMidCooledFresh0h24h48h72h96h0.00.50.91.0
Large muscle · 72h half-lifeSmall muscle · 36h half-life
Fatigue depositexercise.muscles[m] × sets × reps

Each exercise maps to a weighted muscle set. A bench press deposits 1.0 into chest, 0.5 into triceps, 0.4 into front delts. Sets × reps gives the intensity proxy.

Recovery curverecovery = 1 − exp(−hours_since / half_life)

Standard exponential. The half-life is the only knob.

Half-lives, by muscle sizelarge: 48–72h · small: 24–36h

Back, chest, quads, glutes get the longer curve. Biceps, calves, abs, forearms get the shorter one. A muscle reads “fresh” once recovery > 0.9.

Pricing

Lifetime, under ten dollars.No subscription. Ever.

Try free for 3 workouts. No card. No subscription.

One purchase. No item limits. No category paywalls. No pro tier hiding the heatmap. The hero feature is what you bought; we don’t hold it hostage.

AppPriceModelHeatmap?
BodyAtlasLifetime, under $10One-time
Fitbod$12.99/mo or $79.99/yrSubscriptionBehind sub
Strong$4.99 lifetimeLogger only, no heatmap
Hevy Pro$2.99/mo or $74.99 lifetimeLogger + social, no heatmap

Competitive pricing surveyed against the 2026 strength-app market.

Now on the App Store

Built for lifters who payonce, not forever.

BodyAtlas is live. iPhone only. iOS 26+. Lifetime purchase under ten dollars. Free for your first three workouts.

Download on theApp Store
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