Comparison

Pacing vs Mast'O

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Pacing

This app helps individuals with ME/CFS manage their activity levels by monitoring heart rate against personalized thresholds. It provides visual cues and alerts to prevent overexertion and potential relapses, integrating with Apple Health for comprehensive tracking.

Highlights
  • Activity management for ME/CFS
  • Personalized heart rate thresholds
  • Relapse prevention alerts
  • Visual heart rate zone indicators
  • Apple Health integration
  • Apple Watch exclusive
Features
Read full description

Pacing is an activity management strategy to help ME/CFS patients limit the number and severity of relapses while remaining as active as possible. For ME/CFS patient-pacing purposes the heart rate threshold is set at a percentage of the peak heart rate. The app uses the formula (220 - age) * 0.55. The app also considers the average resting heartbeat of the last 14 days. A heartbeat above 15 beats of the average resting heartbeat is also considered as too much. This app can give you clues, but it does not replace taking care of yourself and taking it easy if needed. The app is for the Apple Watch only and will not be displayed on the iPhone. Press the Digital Crown on the Apple Watch to go to the Home screen. There you will find the app. We use the following rules: Heart rate is greater than the average resting pulse + 15 in the last 14 days: red circle 100% filled and a soft click. Heart rate is smaller (220 - age) * 0.36: light, green circle 16% full Heart rate is smaller (220 - age) * 0.38: medium, green circle 32% full Heart rate is smaller (220 - age) * 0.40: hard, yellow circle 48% full Heart rate is smaller (220 - age) * 0.45: very hard, yellow circle filled to 64%, soft clicking Heart rate is smaller (220 - age) * 0. 55: cautious, yellow circle filled to 80%, soft clicking Heart rate is larger: red circle filled to 100% and a short warning tone Pacing integrates with the Apple Health app. Disclaimer: The app was developed in consultation with physicians who treat ME/CFS patients. However, the App does not provide medical advice or endorse any treatment or medical procedure. The information contained in the App is not intended to be a substitute for professional medical advice, diagnosis or treatment. Your reliance on any information provided by the App is entirely at your own risk.

About

Mast'O

Features
Read full description

Application pour smartphones et tablettes destinée aux personnes atteintes de mastocytoses ou syndrome d’activation mastocytaire (SAMA). Cette application contient de nombreuses fonctionnalités pour vous aider au suivi de votre maladie dans votre vie quotidienne. Parmi ces fonctionnalités : - Une page profil pour renseigner les informations importantes de votre dossier médical (antécédents, allergies etc…) - Un répertoire pour enregistrer les coordonnées de vos médecins. - Un journal de bord pour documenter vos symptômes, état de santé et/ou moral. - L’ajout de photos pour vos symptômes visibles. - Un porte document pour toujours avoir vos documents importants sur vous comme les comptes rendus d’examens. - Créer des rappels pour vos rendez-vous. - Préparer votre prochain rendez-vous avec votre médecin. - Créer des rappels pour vos prises de médicaments. - Un historique de vos traitements. - Des liens vers les recommandations spécifiques à la maladie utiles aux professionnels de santé qui prennent en charge et vers la carte des centres maladies rares - Générer un rapport PDF pour partager facilement vos observations. - Un thème contrasté pour un affichage optimisé pour de forts contrastes. - Ajout de symptômes fréquents pour enrichir vos observations plus rapidement. - Un menu “Paramètres & données” pour gérer vos thèmes, exports et imports depuis un seul endroit. - Import/Export pour sauvegarder et restaurer vos données sécurisées sur un nouveau téléphone en toute simplicité. Aucun compte n’est requis. Les données sont stockées sur votre appareil et non sur un cloud. Une fonction d’export des données est prévue pour que vous puissiez migrer vos données vers votre nouvel appareil si besoin.

Screenshots

Mast'O4 screens

Verdict

The call

The clearest difference is update cadence: Pacing at every 4 days against Mast'O's every 15 months. Mast'O's advantage is iOS requirement (14.0 vs 16.6). On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Pacing ships an update every 4 days, Mast'O every 15 months. The most recent releases landed on October 14, 2026 and October 5, 2026 respectively.

Scorecard2 real differences · 6 level
Pacing versus Mast'O: the parameters behind the verdict, then further details
ParameterPacingMast'O
PriceFreeFree
Positive reviews0.0% of reviews—
Update frequencyEvery 4 days — betterEvery 15 months
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, Apple WatchiPhone, iPod
Requires iOS16.614.0 — better
Further details — not scored
Size1 MB26 MB
Age rating4+12+
DeveloperQ_PERIOR AGFilière MaRIH

In-app purchases

None

Pacing

No in-app purchases

None

Mast'O

No in-app purchases

Questions

Is Pacing free?
Pacing is free to download, with no in-app purchases.
Is Mast'O free?
Mast'O is free to download, with no in-app purchases.
Do Pacing or Mast'O have ads?
Neither Pacing nor Mast'O shows ads.
Which is updated more often, Pacing or Mast'O?
Pacing ships an update every 4 days, and Mast'O every 15 months. Most recently, Pacing was updated on October 14, 2026 and Mast'O on October 5, 2026.

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