# TG Alertness — Predict fatigue risk

> Predict fatigue risk (iPhone/iPad app by Tyler Grange LLP.)

- Source: https://appshunter.io/ios/app/tg-alertness/id1605388268 (this page in markdown: same URL + `.md`)
- Developer: [Tyler Grange LLP](https://appshunter.io/developer/1605388270)
- Category: Health & Fitness
- Price: Free
- Age rating: 4+
- Requires: iOS 9.0 · 32 MB
- Languages: English
- Released: 2022-01-16
- Data updated: 2026-06-11
- User reviews in markdown: https://appshunter.io/ios/app/tg-alertness/id1605388268/reviews.md

## What is TG Alertness?

The Tyler Grange Alertness app collates user inputs to calculate and predict an individuals' risk from the harmful effects of fatigue.

It uses some mathematical wizardry to combine hours of wakefulness, sleep in the last 24 hours, the Stanford Sleepiness Scale, a reaction time test and circadian rhythm.

All these factors contribute to how tired or alert we are.


## Version history (last 2 releases)

### 1.1.0 — 2022-04-04

-  A new happiness question
- Option to retake the reaction time test after taking it
- Changes to the results page, each section is now coloured to reflect its individual alertness level indication. Each section now starts with a closed drop down, more information is given on tap.

### 1.0 — 2022-01-16

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-11.*