Heart Rate Tracking

Monitor your heart rate during workouts for better training insights.

Heart Rate Sources

Treadmill Assistant supports up to three heart rate sources (wireless earbuds are iOS-only):

Source	Accuracy	Convenience
External HR Monitor	High - chest straps and arm bands provide reliable, continuous readings	Requires separate device
Wireless Earbuds (AirPods / Beats)	High - optical sensor on supported Apple earbuds	iOS 26+, Premium, Apple Health; hands-free
Treadmill Grip Sensors	Moderate - affected by grip pressure, sweat, and movement	Built into most treadmills

External HR Monitors

Bluetooth heart rate monitors (chest straps, arm bands) provide the most accurate readings. They allow continuous monitoring without holding the treadmill handles.

See Heart Rate Monitor Settings for setup instructions.

Wireless Earbuds (AirPods / Beats)

On iOS, supported Apple earbuds with a heart-rate sensor can supply your heart rate hands-free — shown live in the app and recorded in Apple Health. See Wireless Earbud Heart Rate below.

Treadmill Grip Sensors

Many treadmills have metal contact sensors on the handlebars. These require both hands on the sensors and take 30-60 seconds to stabilize.

Using Treadmill Grip Sensors

Proper Hand Placement

For accurate readings:

Place both hands on metal sensor pads
Maintain firm but relaxed grip
Keep hands relatively still (small movements OK)
Don't grip too tightly (restricts blood flow)

Waiting for Stable Reading

After placing hands on sensors:

Takes 15-30 seconds to get first reading
Another 30-60 seconds to stabilize
"N/A" shows until stable reading acquired
Be patient - don't remove hands too soon!

Heart Rate Display

During Workout

On the main screen, the Heart Rate stat card shows:

Current BPM when receiving data from either source
"N/A" when no signal or unstable
Updates every few seconds when stable

After Workout

In History, expanded workout shows:

Minimum HR - Lowest BPM reached
Average HR - Mean BPM across workout
Maximum HR - Peak BPM reached

These sync to your health platform (if enabled).

Wireless Earbud Heart Rate (AirPods / Beats)

iOS 26 or later · Premium · Apple Health

This feature is iOS-only. It requires iOS 26 or later, a Premium subscription, and Apple Health integration turned on.

If you wear compatible Apple earbuds with a heart-rate sensor (such as AirPods Pro 3 or supported Beats models), Treadmill Assistant can use their heart rate during workouts. The app can't read earbud heart rate directly over Bluetooth, so it starts a live workout session on your iPhone — iOS then collects the earbud heart rate and hands it back to the app.

When this is on, your earbud heart rate:

Shows live in the app — the Heart Rate card displays your earbud BPM (and HR zones), labelled with the earbud name (for example "AirPods Pro").
Is recorded in Apple Health — your earbud heart rate is attributed to the workout in the Apple Health workout view.

Turning it on

Make sure Apple Health is enabled (Settings > Apple Health).
Go to Settings > Heart Rate Monitor.
Turn on Live workout session.

It is off by default. If a live session can't start — for example on an older iOS version — the app quietly falls back to its standard health sync.

Start without waiting for a Bluetooth monitor

If you also have a Bluetooth chest strap or arm band set up but usually work out with just your earbuds, you can skip the "heart rate monitor not connected" prompt:

With Live workout session on, turn on Start without waiting for monitor (shown just below it).
Workouts now start straight away on your earbuds. Your Bluetooth monitor still connects in the background if it's switched on — and if it does, it takes over (it's the most accurate source).

When this setting is off, starting a workout while your Bluetooth monitor is configured but not connected shows a prompt. With Live workout session on, that prompt includes a Use earbuds option so you can start on earbuds with one tap.

Which source wins

If more than one source has data, the app prefers them in this order: a connected Bluetooth monitor first, then your earbuds, then treadmill grip sensors. If your strap drops out mid-workout, earbuds take over automatically.

Granting Heart Rate access in Apple Health

For earbud heart rate to reach the app and Apple Health, the app needs Heart Rate (read) access in Apple Health. If you turned on Apple Health in an older version of the app, that access may never have been requested — so earbud heart rate won't appear, and the permission may not even be listed in the Health app yet.

To fix it:

Go to Settings > Heart Rate Monitor (or Settings > Apple Health).
Tap Update health permissions.
In the Apple Health sheet, turn on Heart Rate (and Workout), then allow.

If the sheet doesn't appear, or the toggles still aren't listed, grant them manually in the Health app:

Open the Health app, tap your profile picture (top-right), then under Privacy tap Apps, select Treadmill Assistant, and turn on Heart Rate.

iOS only asks once

Apple shows the permission sheet only for data types you haven't decided on yet. If you previously declined — or already answered — the Update health permissions button can't re-open that decision; use the Health app steps above instead. (This is an iOS privacy rule, not an app limitation.)

Heart Rate Stabilization

Treadmill Assistant uses smart stabilization to ensure accurate readings.

Why Stabilization Matters

Treadmill HR sensors can show:

Wildly fluctuating values initially
False lows when first touching sensors
Inaccurate spikes during movement

Stabilization waits for consistent, reliable readings before tracking.

How It Works

You place hands on sensors
App monitors incoming HR values
Calculates standard deviation over time
When variation drops below threshold, HR is "stable"
Only then does app start recording min/max values

Configuration

Advanced users can adjust stabilization settings:

Go to Settings > Advanced Settings
Find Heart Rate Stabilization section
Adjust:
- Stability Threshold - How stable readings must be (default: 5 BPM)
- Sample Window - How many readings to analyze (default: 10 readings)
- Max Wait Time - Max wait for stabilization (default: 60 seconds)

Default Settings Work Well

Most users should keep default settings. Only adjust if you have specific needs.

Minimum and Maximum Tracking

When Tracking Starts

Min/max HR only tracked after stabilization:

Prevents false lows from initial erratic readings
Ensures accurate extremes
More reliable data for training analysis

Continuous Tracking

Once stabilized:

Minimum updates if HR goes lower
Maximum updates if HR goes higher
Average calculated from all stable readings

If Never Stabilizes

If hands never stay on sensors long enough:

Min/max show "N/A" in history
Average shows "N/A"
Workout still saved (just without HR data)

Heart Rate Training Zones

Treadmill Assistant can display your current HR zone (1-5) directly on the heart icon during workouts, and track time spent in each zone.

Requires Health Integration

HR zones require health integration with age data. On iOS, this means Apple Health with Date of Birth permission. On Android, enter your date of birth in Settings > Health Connect > Health Profile.

How Zones Work

Your maximum heart rate is calculated using the standard formula:

Max HR = 220 - your age

For example: Age 35 → Max HR = 185 BPM

The five standard training zones are:

Zone	% of Max HR	BPM (Age 35)	Purpose
Zone 1	50-60%	93-111	Recovery, warmup
Zone 2	60-70%	111-130	Fat burning, base fitness
Zone 3	70-80%	130-148	Aerobic endurance
Zone 4	80-90%	148-167	Lactate threshold, performance
Zone 5	90-100%	167-185	VO2 max, sprints

Enabling HR Zones

iOSAndroid

Enable Apple Health integration in Settings > Apple Health (required)
Grant age permission when prompted (or go to iOS Settings > Privacy & Security > Health > Treadmill Assistant)
Go to Settings
Find Heart Rate Zones toggle
Enable it

When you first enable HR zones, the app will request access to your Date of Birth from Apple Health.

Enter your date of birth in Settings > Health Connect > Health Profile
Go to Settings
Find Heart Rate Zones toggle
Enable it

Age Data Required

HR zones will not work without age data. On iOS, Apple Health integration and Date of Birth permission are required. On Android, enter your date of birth manually in health settings.

Privacy

Your date of birth is only used locally to calculate zones. It is not transmitted anywhere.

During Workout

When HR zones are enabled:

The heart icon shows your current zone number (1-5) overlaid in white
Zone updates in real-time as your heart rate changes
If HR is below Zone 1 (<50% max), no number is displayed
Zone time is tracked only while the treadmill is running (not during countdown or pauses)

Zone Distribution in History

After a workout with zones enabled, the expanded history view shows:

Zone Progression Timeline - A horizontal bar showing zone segments in chronological order
Color-coded segments - Each segment is colored by zone (blue for Z1, green for Z2, etc.)
Pause gaps - Gray segments showing when the workout was paused
Zone breakdown - Time spent in each zone with percentages (e.g., "Z2 Fat Burn: 12:30 (45%)")

The timeline provides a visual story of your workout intensity over time, making it easy to see:

How quickly you reached your target zone
Whether you maintained consistent intensity
How much time was spent in each zone
When and for how long you paused

Zone Tracking During Pauses

Zone time is only accumulated while the treadmill is actively running. Pause periods appear as gray gaps in the timeline and don't count toward your zone totals.

Troubleshooting Zones

No zone number showing:

Ensure HR Zones is enabled in Settings
Check that Date of Birth is available (Apple Health on iOS, Health Profile on Android)
Verify heart rate is being detected (needs >50% of max HR to show Zone 1+)

Zone calculation seems wrong:

Verify your Date of Birth is correct
The 220-age formula is an estimate - individual max HR may vary

No Date of Birth permission (iOS):

Go to iOS Settings > Privacy & Security > Health > Treadmill Assistant
Ensure "Date of Birth" is enabled under Read access

Date of Birth not set (Android):

Go to Settings > Health Connect > Health Profile
Enter your date of birth

Using Zones for Training

Zone 1-2 (50-70%): Easy recovery runs, warmups, cooldowns

Zone 3 (70-80%): Steady-state runs, building aerobic base

Zone 4 (80-90%): Tempo runs, improving lactate threshold

Zone 5 (90-100%): High-intensity intervals, sprints (use sparingly)

Troubleshooting Heart Rate

No Heart Rate Showing

Problem: HR shows "N/A" during workout

Possible causes:

Hands not on sensors
Sensors dirty/not working
Too much movement
Treadmill doesn't have HR sensors

Solutions:

Place both hands firmly on handlebar sensors
Clean sensors with damp cloth
Keep hands still for 30-60 seconds
Verify treadmill has HR capability

Erratic Readings

Problem: HR jumping around wildly

Solutions:

Keep hands still
Don't grip too tightly
Ensure good contact with sensors
Wait longer for stabilization
Adjust stabilization threshold in Settings

HR Never Stabilizes

Problem: Always shows "N/A", never gets a reading

Solutions:

Increase stabilization timeout (Settings > Advanced)
Check treadmill sensor functionality
Try different hand positions
Ensure sensors are clean and dry

HR Seems Inaccurate

Problem: Readings seem wrong (too high or low)

Solutions:

Treadmill sensors are less accurate than chest straps
Compare with manual pulse check
Try different grip positions
Clean sensors thoroughly
Consider this normal sensor variance

Improving Heart Rate Accuracy

Best Practices

Clean sensors regularly - Sweat and oil reduce accuracy
Proper grip - Firm but not tight
Minimal movement - Keep hands steady
Both hands - Don't use just one sensor
Patience - Allow time for stabilization

When to Check HR

At start of workout (baseline)
During steady-state portions (for zone training)
At peak intensity (max HR)
During cooldown (recovery rate)

Limitations

Treadmill handlebar sensors:

✅ Good for general monitoring
✅ Useful for training zones
⚠️ Less accurate than chest straps
⚠️ Require hands on bars (limits natural running)
⚠️ Can be affected by sweat, grip pressure

For professional training, consider dedicated HR monitors.

Heart Rate and Calorie Estimation

Experimental Feature

HR-based calorie estimation is a new, experimental feature. Results may vary between individuals.

With Premium and a Bluetooth HR monitor connected, Treadmill Assistant can estimate calories burned using your heart rate data. This provides a more personalized calorie figure than treadmill-reported values alone.

Requirements

Premium subscription
Bluetooth HR monitor connected (chest strap or arm band)
Health profile with biological sex, weight, and date of birth filled in

How It Works

The app uses an established exercise science formula (Keytel et al., 2005) that factors in your heart rate, age, weight, and sex to estimate energy expenditure during exercise. This approach accounts for your individual effort level rather than relying solely on distance and speed.

What You See

When HR-based estimation is active:

Primary value: HR-estimated calories (based on your actual heart rate)
Secondary value: Treadmill-reported calories (shown for reference)

If HR data is unavailable (no monitor connected, or signal lost), the app falls back to the treadmill's calorie value.

Enabling HR Calorie Estimation

Set up your health profile (sex, weight, date of birth)
Connect a Bluetooth HR monitor in Settings > Heart Rate Monitor
Enable HR zones in Settings
HR-based calorie estimation activates automatically during workouts

Next Steps

View your stats - Understand HR min/avg/max
Health integration setup - Sync HR data
Tips & Tricks - Advanced HR training strategies

HR issues? Check Troubleshooting.