
Redline: Sprint Timer
Sprint Intervals for Runners
About
This app simplifies sprint interval training for runners. It provides customizable countdowns, voice cues, and haptic feedback for each sprint and rest period. Sessions sync with Apple Health and can be controlled via Apple Watch and the Lock Screen.
What's New in Redline
1.0.2
September 17, 2026
Cues that keep working when the phone stops paying attention. NOTHING GOES QUIET Turning voice cues off used to leave a locked phone with no cue at all: no sound, no tap, no notification. Now the transitions arrive as notifications instead, and Settings says so. Those notifications are also properly time sensitive, so a Fitness Focus no longer silences them, and they show while you are looking at the screen. IF iOS TAKES THE APP AWAY When iOS reclaims the app mid-session, the queued cues are what carry the rest of your workout. Opening the app back up used to delete them. It no longer does. And coming back after a gap no longer replays everything you slept through in one burst of contradictory instructions; you get the one cue that is actually current. ON THE WATCH A call or a Siri invocation used to kill the voice cues for the rest of the session with no way back. Starting a session used to stop music playing from the Watch itself and never bring it back. Both fixed. If the workout session fails to start, the app now tells you instead of quietly dying at the first wrist down. And the phone's voice and Apple Health switches finally apply on the wrist, which is what the privacy policy always said. HONEST NUMBERS Pausing no longer counts as exercise, in the session total or in Health, and a paused sprint is no longer written to Health as one long interval. The sprint ticks on the Lock Screen and in the app now agree with each other. SMALL THINGS You can end a session from a paused sprint on the phone, and the Watch says how. The lead-in says "Sprint starts on GO" rather than promising a beep that never existed. Settings toggles have VoiceOver labels.
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FAQ
How do I set up a sprint workout in Redline?
Setting up a workout is designed to be quick. You can select the number of sprints, the duration of each sprint, and the length of rest periods. The default setting is six 30-second sprints with three minutes of rest, allowing you to start most sessions with a single tap.
Does Redline have ads?
No, Redline is completely ad-free. The app is designed to provide a distraction-free experience for your workouts, with no advertisements to interrupt your training sessions.
Can I use Redline without my iPhone?
Yes, Redline functions as a full workout app on Apple Watch. You can start sessions directly from your wrist, and transitions will be communicated via haptic taps and voice cues if you are using AirPods.
How does Redline sync with Apple Health?
Every completed session in Redline is automatically saved to Apple Health as a high-intensity interval workout. Each sprint within the session is recorded as a distinct segment, and if run from the Watch, it also includes heart rate and energy expenditure data.
What is the age rating for Redline?
Redline has an age rating of 4+. This indicates it is suitable for users of all ages, with no content restrictions.
How often is Redline updated?
The latest version of Redline is 1.0.2, which was last updated on September 17, 2026. While specific update frequency isn't detailed, this indicates recent maintenance and potential for future improvements.
What makes Redline different from other interval timers?
Redline focuses on simplicity and a distraction-free experience. It avoids accounts, logins, and subscriptions, offering only the core functionality of a sprint timer with clear voice cues and seamless integration with Apple devices.
Is Redline available on other devices besides iPhone and Apple Watch?
Currently, Redline is designed for iPhone and Apple Watch. The app leverages the unique features of these devices, such as haptic feedback on the Watch and Live Activities on the iPhone's Lock Screen.




