HIIT 4x4 12+
Interval Training Meter
Eastridge Technology
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- $4.99
Screenshots
Description
HIIT 4x4 is an Apple Watch exercise monitoring app for High Intensity Interval Training (HIIT). The app sequences exercise between high and low intensity intervals. The intensity of the exercise is measured as a percentage of a person's Maximum Heart Rate (MHR).
The HIIT 4x4 intervals are as follows:
- 10 minutes warmup at 60% MHR
- 4 minutes high intensity at 90% MHR
- 3 minutes low intensity at 70% MHR
- repeat high-low intervals 4 times (4 high intensity intervals of 4 minutes each = 4x4).
HIIT 4x4 uses a speedometer type dial to display heart rate. When the arrow is in the green zone then your heart rate is within the interval target. If the heart rate later falls out of the target range, warning chimes are issued until back in range.
Each person's MHR is different, and changes with age. A commonly used formula for MHR is 220 - age in years. A more accurate number can be discovered by using a heart monitor during all out exercise and observing the highest heart rate achieved.
HIIT 4x4 stores your workout history using Apple Health.
HIIT 4x4 is based on the High Intensity Interval Training 4x4 program developed by the Norwegian University of Science and Technology's Cardiac Exercise Group.
What’s New
Version 1.08
Start button moved to Settings screen to streamline operation.
Ratings and Reviews
Worked until today
This was a great app for a Norwegian 4x4. Its simplicity was a strength. However, with the latest WatchOS, it will no longer start up via the watch touchscreen on my v8 cellular watch. Bummer.
My 3 stars is the average of a 5 and a 0, sort of. Hoping this gets fixed.
After a delay, here’s an update. The app did start working again after a week or so. My initial POV of good simplicity fell away when I realised that it was merely reporting HR data, but not any GPS, pace, cadence, stride, etc.
I tried using the Apple workout app simultaneously, but HIIT would lock up. Because this app used the same audio alert for starting/stopping an interval and being in the target HR or getting too high or low, I completely missed starting an interval. When I cancelled this app, and just used the built in Timer app, I discovered that my Workout app had been stopped as well.
I just deleted this completely. Waste of time.
No info on Charges
Never really used the app. I can’t find a place where I can cancel the charges on this app if I decide I don’t want to keep using it. I paid $1.99 but it’s not clear if it renews automatically or is it just a one time charge.?. Doesn’t show on subscriptions on iPhone. Frustrating.
Developer Response ,
The price is a once only purchase, not a subscription. Please apply to Apple for refunds, google "apple app store refunds"
Not worth the money
I spend too much time looking at my watch to see where my heart rate is at. It distracts from the actual work out. This was a waste of 2 bucks. Avoid!
Developer Response ,
The app emits tones when you are in the right heart range and when time intervals end -- you don't need to look at it.
App Privacy
The developer, Eastridge Technology, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.
Data Not Collected
The developer does not collect any data from this app.
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Information
- Seller
- Eastridge Technology
- Size
- 18.5 MB
- Category
- Health & Fitness
- Compatibility
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- iPhone
- Requires iOS 12.0 or later.
- iPod touch
- Requires iOS 12.0 or later.
- Apple Watch
- Requires watchOS 5.0 or later.
- Apple Vision
- Requires visionOS 1.0 or later.
- Languages
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English
- Age Rating
- 12+ Infrequent/Mild Medical/Treatment Information
- Copyright
- © 2025 Eastridge Technology
- Price
- $4.99
Supports
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Family Sharing
Up to six family members can use this app with Family Sharing enabled.