Entrain 4+

The University of Michigan

Designed for iPhone

    • 2.6 • 19 Ratings
    • Free

iPhone Screenshots


Entrain is a mobile application that uses your lighting history, activity, and heart rate to recommend schedules of light and dark. These schedules are able to shift a model of the circadian clock to a new time zone as quickly as possible. Users can opt-in to share their data with the University of Michigan for research purposes.

What’s New

Version 3.4

This app has been updated by Apple to display the Apple Watch app icon.

Added more explanations, bug fixes

Ratings and Reviews

2.6 out of 5
19 Ratings

19 Ratings

Jamie El ,


The light suggestions are interesting and sometimes counterintuitive. When I often thought it would be best to get up early and force myself into local schedules, the app would say otherwise. When I followed the app, I generally felt better.

- it has a place for Apple Watch data but there is no way I can discern to actually allow the app to use that data.
- in the space of 5 minutes the suggested time that I was supposed to seek light until changed by hours. Not sure what happened there.

Ima_cat_2 ,

Confusing and not very functional

Very confusing to use. I was hoping to use this app to counter long jet lag adjustments on my trips between Eastern and Western countries. Unfortunately I’m so confused about the time notation, and it makes me feel quite stupid. If I’m following correctly, the the app is simply suggesting that I avoid light for 12 hours and avoid dark for 12 hours each day for about 4 days, and then (hurrah!) my schedule is complete. BUT the daily suggested schedule is only maybe 30 minutes off my final target sleep/wake times. Really? Maybe the schedule is this way because of the complete reversal of day/night in Eastern and Western countries, but I didn’t need an app to tell me to just force myself to be awake during the day and asleep at night to adjust. OR maybe I’m a complete dunce and I’m reading the time notation wrong. If that’s the case, how does being awake at night for days on end somehow magically help me adjust in 4 days. Its just a little muddled and unclear in the delivery. The jet lag on these trips can be so brutal and stubborn, I was hoping for something more gradual and merciful- like maybe how I can intelligently work in naps or shorten/lengthen my night time sleeping.... it definitely was not so. But then again... nothing about a West to East transition is that way, so maybe my expectations were simply unrealistic.

Chi Chi Gonzales ,

Great potential, but buggy. Or just not well-explained.

As a frequent traveler (2-4 trips per month, US-Europe, Asia, & deep South America), I was excited to learn about an app like Entrain.

I’m just using it on my first trip and noticing some basic omissions and, what appear to be, some bugs:

1. Upon installation, there was no tour or tutorial explaining how to optimally use the app; only a few questions.

2. There aren't any recommendations on when to start “adjusting” prior to starting a trip. 12 hours prior? 24 hours?

3. There aren’t any notifications (badges, alerts, etc) for when a “seek light/dark” period is starting. Also, no Apple Watch integration for the notifications.

4. (Bug?) The “seek light/dark” times keep changing. Sometimes by minutes, sometimes by hours. Sometimes in the middle of a period.

5. (Bug?) When setting a trip end time, it changes the time to other than what is selected. For instance, our arrival time was 10:50a (GMT-3). The app kept changing this to 12:50p (GMT-3).

6. The UI for changing the “Normal Lighting Schedule” is maddeningly frustrating. Could be much more user-friendly.

Like the review title says...HUGE potential for this app, but needs some tweaks or better explanations for use.

App Privacy

The developer, The University of Michigan, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.

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