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Apple Health for Serious Lifters

Most Apple Health integrations in fitness apps are an afterthought: save a generic session, call it a day. Anvil Workout does it properly — writes real Traditional Strength Training sessions, logs sets via a native Apple Watch companion app, tracks active calories/heart rate, and keeps your private data on-device.

What gets written to Apple Health

When you finish a workout, Anvil Workout writes a Traditional Strength Training workout session to Apple Health. The session includes:

• Start and end time of the workout
• Duration (excluding any time you paused)
• Workout type — strength training, marked as indoor

The session shows up in the Health app alongside your runs, cycles, and any other logged activity. If you have third-party tools that read Health — trainer dashboards, nutrition apps, research studies — your lifting activity is now visible to them like any other workout.

What gets read from Apple Health

During a workout, if your Apple Watch is logging heart rate and active energy for the same time window, Anvil Workout can surface those metrics on your session summary:

• Active energy burned (calories) during the workout
• Average heart rate across the session

Both numbers are pulled from Apple Health after the workout ends, and only for the exact time window of your session. They appear in your Anvil Workout history view next to the workout you completed.

How Apple Watch fits in

Anvil Workout includes a native watchOS companion app that integrates with the active workout on your iPhone. You can check off reps, complete sets, and skip exercises directly from your wrist, so you don't have to keep picking up your phone. When a rest timer starts, a circular progress view and live countdown appear on your Watch, complete with a haptic wrist-tap alert when the timer hits zero.

Practical setup:

1. Launch a workout on your iPhone. The Apple Watch companion app automatically synchronizes and displays your active set.
2. Perform your exercises and log sets from either device—changes sync instantly over local connectivity.
3. While you lift, your Apple Watch continues to track active energy (calories) and heart rate in the background.
4. When you complete your workout, Anvil Workout queries HealthKit for the heart rate and active calories recorded during your session and links them to your history.

If you don't wear a Watch, Anvil Workout still saves the workout — heart rate and calories just won't appear on that session.

Privacy and permissions

Apple's HealthKit is one of the strictest privacy frameworks on iOS. We think that's a good thing.

• The first time you start a workout or tap "Grant Access" in Settings, iOS shows Apple's own permission dialog listing exactly what Anvil Workout wants to read and write. You approve each category individually.
• You can change permissions any time in Apple's Health app → your profile → Privacy → Apps and Services.
• If you revoke write permission, Anvil Workout stops saving workouts to Health. If you revoke read permission, we can't show calories and heart rate on session summaries.
• Anvil Workout never transmits Health data off your device. Apple's framework handles all access on-device; we simply ask for the data and display it.

Why most workout apps skip this

HealthKit integration takes real work: permission flows, background fetches, workout builder APIs, correct unit handling, and respecting Apple's privacy boundaries. A lot of subscription-based fitness apps either skip it entirely or write a generic "Other" workout type that doesn't integrate with the rest of the Health ecosystem.

Anvil Workout was built around HealthKit from the start. It's a local-first app, and Apple Health is the local-first fitness platform. The integration is natural.

What Anvil Workout doesn't do (yet)

We're honest about the gaps:

• No standalone Apple Watch tracking (without phone). The Watch app operates as a companion view for the workout running on your iPhone; it does not record standalone sessions without your phone nearby.
• No HealthKit history read. We don't read past workouts from Health and pull them into Anvil Workout's history. Our history view only shows sessions you logged with us directly.
• No body weight or body measurements. Anvil Workout focuses on lifting performance. If you track weight in the Health app, it stays there.