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By The University of Michigan

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Learn how to use Entrain at Jetlag is the result of a disrupted circadian clock. Entrain simulates your circadian clock on the phone and makes mathematically optimal lighting recommendations to help you adjust as fast as possible to new timezones and schedules. The recommendations, which tell you when to seek light and/or dark, are based on new search in the journal PLoS Computational Biology. For more information visit

What's New in Version 2.0

- Updated user interface
- New lighting logging system
- Expanded help section
- Expanded jet lag rating system
- Added new cities to time zone list
- Added export option for lighting history

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Customer Reviews

Great concept, poor execution

I just got back from a trip from china and wanted to use this app. I love the fact that it is data driven and shows graphs. I really had trouble telling it I was getting back from a trip and that I spent 18 hours traveling. I like that you can edit your past data, but I couldn't tell it I got home yesterday. Then once I think I got everything entered correctly, it just told me when to seek light and dark, not when to actually sleep or stay awake. I has a lot of issues trying to get this to work. I might have done something wrong, but it still means it is not intuitive to use. I eventually gave up and uninstalled this app, much to my disappointment. It had everything I was looking for, but was just too difficult to use...

Great idea; more data options needed

I really wanted to like this app but I couldn't figure out how to submit my data for my real world situation. That would be, AFTER my travel rather than the ideal situation of before the travel.
In my opinion it needs one more set of travel input fields: point of origin, date, time. It also would be helpful if dates / times before "today" could be input.
Then I could log in the fact that I left Melbourne two days ago and got back - the same date that I left; earlier in the day; and after having spent 27 hours traveling across 16 time zones.
I'd love to see the app's recommendations for how to use light to recover from this travel. Without a point of origin, the app seems very difficult to use.

Doesn't allow for real travel data

I just returned from Asia to US. But I can't enter those travel dates as the app only allows for predicted travel. I will try again for future trip. Even so, we all know that flights change more often than not especially for intercontinental travel. It seems like the app should allow for back data (actual travel rather than predicted) - at least for up to a few days after arrival. I'm going to try to fool the app by entering my travel as upcoming. But this is a small design flaw with big implications for research as real data cannot be entered.

View in iTunes
  • Free
  • Category: Travel
  • Updated:
  • Version: 2.0
  • Size: 7.7 MB
  • Language: English
  • Seller:

Compatibility: Requires iOS 7.1 or later. Compatible with iPhone, iPad, and iPod touch.

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