Treeline FAQ

Treeline is a fitness and workout tracking app that is designed primarily for people who enjoy the outdoors and record heart rate data during their activities. The heart rate data allows the app to calculate fitness, fatigue, and load scores over time based on TRIMP models.

An iPhone or iPad running iOS or iPadOS 18 or later, and workouts saved to Apple Health. An Apple Watch is the most common source, but any device or app that writes workouts to Apple Health works. Treeline is not available for Mac or Apple Watch. Some features need more: heart rate data is required for fitness, fatigue, and load; overnight heart rate, heart rate variability, and sleep data (typically from an Apple Watch worn to bed) are required for the readiness, sleep, and stress scores; and the Daily advice note requires a device that supports Apple Intelligence.

Treeline explains what it reads, asks for permission to read your Apple Health data, lets you choose which sources (Apple Watch, other apps) to include, and asks for your resting heart rate, maximum heart rate, and a sex setting that selects the constants used by the Banister TRIMP model. It then imports your history one month at a time with a progress indicator. You can browse the app while the import runs. Treeline only ever reads from Apple Health. It never writes to it.

Yes. Treeline will use any activity saved to Apple Health that has heart rate data to calculate fitness, fatigue, and load scores. Of course, GPS routes, distance, and pace will not be included unless the app that recorded the workout saved this information (e.g., Zwift, Rouvy, Peloton, etc.).

Yes, you can. However, the fitness, fatigue, and load tracking is not available from the heart rate itself. Those scores are calculated using TRIMP models, and those models require heart rate data to accurately gauge exertion levels. You can still rate how hard a workout felt (see “What if a workout has no heart rate data?” below). All other data not dependent on heart rate is available to you including maps, distance, speed, calories, goals, elapsed time, etc.

No. Treeline was built with a privacy-focused mission and infrastructure due to a need for more privacy than other similar apps offered. Treeline has no account, no server, no analytics, no advertising, and no third-party code. It reads your activity data from Apple Health and processes it on your device. I never receive your data and cannot see it. The things you create in Treeline (notes, ratings, equipment, heart rate profiles, goals, and settings) can sync between your devices through your own private iCloud account, which only you can access. Your data is never shared with anyone. This will never change. For the full details, see the Treeline Privacy Policy.

A few, and each only for a specific purpose: iCloud, to sync the things you create between your devices; Apple Maps, to draw the route of a workout; Apple’s location services, to work out which time zone a workout happened in (this sends a single coordinate from a workout you open, never in bulk and never in the background); and Apple’s on-device language model, to write the optional daily advice note (that text never leaves your device).

The name is only used to make the experience a little more personalized and friendly. For now, it only appears at the top of the Today screen. You can skip the name input altogether if you are not comfortable with it. You could input your real name, you can input a nickname, or you can input something fun and motivational just for you. The name will sync to your other devices (as long as you are logged into the same Apple Account on that device), but other than that, the name goes nowhere.

Treeline never changes anything in Apple Health, so manage your workouts and health data there. The local cache Treeline builds is removed when you delete the app. The notes, equipment, and settings you created are stored in your private iCloud database, and deleting the app does not delete them. To remove them, go to Settings > [your name] > iCloud > Manage Account Storage > Treeline.

Yes, it is. Just tap on a workout to view the Workout Summary page. Then tap Edit Workout Details. You can change the title of the activity and add notes. Tap the Save button when you are done.

Yes, you can. Head over to Settings > Equipment and tap the + button to add shoes, bikes, or any other kind of equipment you want to track. If you are just starting out on Treeline and your shoes already have 250 miles of use, you can input the starting mileage as well. Once the equipment is added, when you visit a Workout Summary page and tap Edit Workout Details, you will have the option to designate that equipment for the workout. The mileage for that workout will be added to the total mileage for the equipment.

Treeline will ask you to rate how hard the workout felt on a scale of 1 to 10 (1 is barely any effort, 10 is the hardest you can go). It multiplies that rating by the workout’s duration to estimate the load, and estimated values are shown differently from measured ones. If you skip the rating, the workout appears as “No load calculated” and is left out of your fitness and fatigue numbers. You can also rate workouts that do have heart rate data. Those ratings never replace the measured value; they help Treeline learn how your effort ratings translate into load so its estimates get better over time.

If two devices or apps record the same session (for example, an Apple Watch and a bike computer syncing through Strava), Apple Health holds two workouts. Treeline treats any two workouts that overlap in time as the same session, even if they have different activity types, and counts only one of them. It prefers the record with heart rate data, then more heart rate samples, then a route, then the longer duration. Nothing is deleted. The one that loses is simply set aside. If Treeline cannot tell which is better, it asks you, and you can choose to keep one just this time or to always prefer that source from that date forward. A choice to “always prefer” never rewrites your earlier history. You can review these under Settings > Duplicates.

Yes. Go to Settings > Sources to turn a source off. Turning a source off treats all of its data, past and future, as invalid, so use it only when a source’s data is genuinely wrong. You do not need to turn a source off to fix duplicates. Treeline handles those on its own. When a new source appears in Apple Health, Treeline turns it on by default and lets you know.

A deleted workout stops counting toward everything immediately. However, some apps delete and rewrite a workout when they sync, so Treeline holds on to it for 30 days under Settings > Pending deletions. If an identical workout comes back, its notes and equipment come back with it. From that screen you can also restore a workout or delete it permanently (which also destroys its notes and equipment assignment).

A workout counts toward the calendar date on which it started, in the time zone where it started. Most apps record the time zone, but when one does not, Treeline assumes the time zone your device was in at import and corrects it when you open the workout (using its route) if it turns out to be different. This only matters for workouts recorded in another time zone near midnight.

Yes. Treeline allows you to set a single weekly mileage, workout, time-based, or elevation gain goal. If you are training for a marathon, and your training plan calls for 25 miles this week, head to Settings > Goals to set your weekly goal to 25 miles. If you are training to climb Mt. Whitney for the first time, and your goal is to climb 4,000 feet this week, you can do that too. You can select what activity types count toward your goal, what day your training week starts, and your target. Or maybe you don’t currently have a goal in mind, but you still want to see how much time you spent on the bike this week without a goal. That’s also possible.

TRIMP (Training Impulse) is a single number that estimates the total physiological load of a workout by combining exercise duration with heart rate intensity. The two most common calculation methods weight intensity differently, which is why the same workout can produce different TRIMP scores depending on which model is used. Treeline allows the user to choose between the Banister and Edwards TRIMP models under Settings > TRIMP model. Every workout keeps both values, so you can switch at any time without re-importing anything. The two are on different scales, so Treeline never mixes them in one chart.

Banister TRIMP looks at how hard your heart was working for every minute of the workout, measured as a percentage of your heart rate reserve (the range between your resting and maximum heart rate). Each beat-per-minute level is weighted exponentially, so high-intensity effort counts disproportionately more than low-intensity effort of the same duration, and the results are added up. Treeline does this for each heart rate level you spent time in rather than from the workout’s average heart rate, which matters for interval sessions where the average hides the hard efforts. Because of this, Treeline’s numbers can differ slightly from other tools. The model needs your resting heart rate, your maximum heart rate, and the Male/Female setting, which selects the published weighting constants. It is often preferred by endurance athletes tracking cumulative fatigue over weeks.

Edwards TRIMP divides the workout into five heart rate zones, multiplies the minutes spent in each zone by that zone’s number (1 through 5), and sums the results. With the default zones those are 60%, 70%, 80%, 90%, and above 90% of maximum heart rate. Intensity weighting increases in even steps rather than exponentially. Treats each zone jump as a fixed increment, making it simpler to compute and interpret, and it is common in general fitness apps. It uses your zone boundaries, so it needs a valid heart rate profile (a maximum heart rate above your resting heart rate).

Treeline uses five zones based on a percentage of your maximum heart rate. By default, each zone tops out at 60%, 70%, 80%, and 90% of your maximum, and Zone 5 runs from 90% up to your maximum. With a maximum of 185 bpm, for example, the zones top out at 111, 130, 148, and 167 bpm. Time below the top of Zone 1 counts as Zone 1. Your maximum heart rate is the number you enter during setup or under Settings > Heart rate. Treeline doesn’t estimate it from your age or detect it from your workouts. Note that zones are a percentage of your maximum, while the Banister model uses heart rate reserve. Zones are used to calculate Edwards TRIMP.

Yes. Go to Settings > Heart rate. Under Zones you can set where each of the first four zones tops out, and Zone 5 covers everything above. The boundaries must increase from one zone to the next. Until you edit a zone yourself, the zones follow your maximum heart rate automatically.

Yes. Treeline allows you to choose if you would like to change your heart rate settings (maximum, resting, or zones) for all past activities or to set new values only for future activities. You can change them and choose how far back they apply by navigating to Settings > Heart rate. Treeline never deletes an old profile, so a past season’s maximum heart rate is preserved, and everything is recalculated instantly without needing to re-import from Apple Health.

Your resting heart rate is shown in the Health app (Browse > Heart > Resting Heart Rate); use a typical recent value. Your true maximum heart rate is best found from a hard, all-out effort. Age-based formulas such as 220 minus your age are only rough estimates and can be off by 10 beats or more, which shifts every zone and every TRIMP score. If you leave the setup values alone, Treeline starts with 60 bpm resting and 185 bpm maximum, so it is worth entering your own.

These come from your training load over time. Fitness is a slow-moving average of your daily load (about 42 days), so it rises gradually with consistent training. Fatigue is a fast-moving average (about 7 days), so it jumps after hard efforts and fades quickly. Form is fitness minus fatigue: a positive number means you are fresher than your recent training would suggest, and a negative number means you are carrying fatigue. Rest days count as zero load, so fatigue fades with elapsed time, not just with the number of workouts. These are calculated from the TRIMP model you picked, and you can see them on the Fitness screen.

They are rolling totals for the last seven days (duration, distance by activity type, elevation gain, and your load). You can choose which sport tiles appear and their order in Settings > Appearance.

Readiness is a 0–100 score of how ready you are to train hard today. Half of it is how your body looks after last night (your overnight heart rate variability, your sleeping heart rate, and your sleep score, each compared with your own normal over the last 60 nights). The other half is your recent training load. Scores under 40 read Low, 40–69 read Moderate, and 70 and above read High. If your training state is Fatigued, readiness is capped in the Moderate range no matter how good the night was.

Sleep score is a 0–100 score for your main sleep of the night (naps are ignored). It combines duration against your sleep goal (30 points), deep sleep (20), REM sleep (10), bedtime consistency compared with your previous two weeks (15), and interruptions (25). Going to bed earlier than usual is never penalized. You can set your sleep goal (8 hours by default) in Settings > Goals.

Stress looks at the heart rate readings from your day, leaving out workouts and a short recovery window after them so exercise never counts as stress. The more of your day your heart rate spends meaningfully above your own resting baseline, the higher the score. If your watch also records heart rate variability during the day, that is blended in.

Each score needs certain data. Sleep score needs a night of sleep data; stress needs heart rate readings from the day, which means your watch must be worn; and readiness needs overnight data. Bedtime consistency needs at least five of the previous thirteen nights, and when a piece is missing Treeline scores what it has and tells you. Check that Treeline has permission for each Health category under Settings > Privacy & Security > Health > Treeline.

There are two ways to measure heart rate variability, and they cannot be compared with each other. Newer Apple Watches running iOS 27 can record RMSSD. Treeline scores RMSSD only once it has 14 nights of it to compare against, so for about two weeks after you start recording RMSSD, readiness continues to use SDNN.

It is a short note summarizing your day in plain language, such as what your training and recovery suggest, and it mentions a specific recent workout when that is what is driving the advice. It is written on your device using Apple’s on-device language model, so the text never leaves your device. You can turn it off or choose a short, medium, or long note in Settings > Appearance.

Yes. Navigate to Settings > Appearance. You can change the units for distance, elevation, pace or speed, and energy.

Absolutely. Treeline imports all activities including cycling. You may want to navigate to Settings > Appearance and change the Pace or speed units to “Speed” instead of “Pace.”

Yes. Treeline uses Apple’s system accessibility feature. It is recommended that you customize Control Center on your iPhone and/or iPad to display the Text Size control. Then you can choose to increase the font size of Treeline specifically or all apps directly from Control Center. Alternatively, you can customize visual accessibility settings for specific apps on iPhone from System Settings > Per App Settings.

Yes. Navigate to Settings > Appearance and select the Dark theme. Alternatively, you can set Treeline to follow the system theme.

Yes. Although I very much enjoy the topo line background, everyone has different needs. Navigate to Settings > Appearance and turn off Contour lines at the bottom of the screen.

Treeline is currently available for iPhone and iPad (iOS and iPadOS 18 or later).

No. There are no plans to build Treeline for Android.

Treeline reads your workouts directly from Apple Health on each device, so the device needs to be signed in to your Apple Account with Health syncing through iCloud turned on. If the iPad is signed in to your spouse’s account, it will show their data instead. The things you create in Treeline, such as goals, equipment, notes, appearance settings, and heart rate profiles, sync between your devices through the same Apple Account. Give it a little time after installing, because the first import can take a while.

There could be a few different reasons for this. First, Apple Health sometimes needs time to process a workout. Confirm the workout exists in Apple Health. If it does, try tapping the sync button in the upper right of the Today page, Fitness page, or Workouts page. If that doesn’t work, verify you’ve enabled all permissions in the system settings by navigating to Settings > Privacy & Security > Health > Treeline. Also check Settings > Sources to make sure the app or device that recorded the workout has not been turned off, and Settings > Duplicates in case Treeline set it aside as a copy of another workout. If permissions are turned on, try waiting a couple of hours to see if Apple will reveal the workout to Treeline.

Yes. Treeline works with the data already on your device. Only a few things need a connection: the map tiles behind a workout’s route, the one-time time zone lookup for a workout, and iCloud sync of your notes and settings.

For current subscription prices, go to Settings > Account.

Email support@treelinefitnessapp.com.