# PHS vs Was It Fatigue?

The clearest difference is in-app purchases: PHS at none against Was It Fatigue?'s 2. PHS also leads on iOS requirement (8.0 vs 14.0). Was It Fatigue?'s advantage is update cadence (every 2 weeks vs every 11 months). On price, ads and device support there is nothing between them.

Both are free to download. Was It Fatigue? sells 2 in-app purchases, starting at $500.00 per month. PHS asks for nothing beyond the download.

PHS ships an update every 11 months, Was It Fatigue? every 2 weeks. The most recent releases landed on October 23, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | PHS | Was It Fatigue? |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/phs/id1148768952/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 11 months | **Every 2 weeks** |
| Monetization | Free | — |
| Size | 4 MB | 29 MB |
| Requires iOS | **8.0** | 14.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [Kelly Johnstone](https://appshunter.io/developer/1148768951) | [SleepFit](https://appshunter.io/developer/1353225477) |

## What reviewers say

### PHS

[App page](https://appshunter.io/ios/app/phs/id1148768952)

This app analyzes and interprets thermal risk by calculating predicted heat strain based on user-entered data and ISO 7933:2004 formulas. It offers graphical illustrations and summaries to help manage thermal risks associated with tasks or environments.

**Highlights:** Thermal risk analysis, Predicted heat strain calculations, ISO 7933:2004 formula application, Graphical illustration of heat strain, Thermal risk management guidance

**Features:** macOS Compatibility

**In-app purchases:** none


### Was It Fatigue?

[App page](https://appshunter.io/ios/app/was-it-fatigue/id6737959822)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Was It Fatigue? - Monthly | $500.00 | per month |
| Was It Fatigue? - Annual | $549.99 | per year |


## Frequently asked questions

### Is PHS free?

PHS is free to download, with no in-app purchases.

### Is Was It Fatigue? free?

Was It Fatigue? is free to download, with in-app purchases available.

### Do PHS or Was It Fatigue? have ads?

Neither PHS nor Was It Fatigue? shows ads.

### Which is updated more often, PHS or Was It Fatigue??

PHS ships an update every 11 months, and Was It Fatigue? every 2 weeks. Most recently, PHS was updated on October 23, 2026 and Was It Fatigue? on October 12, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*