Heart Rate Alerts: High & Low Thresholds

By John Ganotis, Beat Watcher’s developer · Updated

Beat Watcher lets you set both a high and low heart rate threshold on your Apple Watch. When your BPM crosses either limit, you get instant haptic vibration and audio feedback. Here’s how to set them up.

Setting your high threshold

The high threshold alerts you when your heart rate goes above a BPM you choose. This is the main threshold you see on the Beat Watcher home screen.

1

Open Beat Watcher

Your current heart rate and threshold are displayed on the main screen.

2

Turn the Digital Crown

Turn the Digital Crown to adjust the threshold to your desired level. Range: 30–250 BPM.

3

Done

Your threshold is saved automatically. Beat Watcher will provide haptic and audio feedback when your heart rate goes above it.

Beat Watcher showing 72 BPM with threshold set to 80

Adding a low threshold

Low Alerts notify you when your heart rate drops below a value you set. Useful for monitoring bradycardia or staying aware of significant heart rate drops during rest or sleep.

1

Open the menu

Tap the top part of the screen that shows your heart rate and threshold.

2

Enable Low Alerts

Tap Settings, then tap Low Alerts. Turn on the Low Alerts toggle.

3

Set your level

Use the Digital Crown to adjust between 30–150 BPM. You’ll receive haptic and audio feedback when your heart rate drops below this value.

Beat Watcher Low Alerts editor

Range Mode: fewer alerts between High and Low

Range Mode is an optional setting for fewer, more focused alerts while you monitor the range between your High and Low thresholds. Beat Watcher alerts once above High, then once below Low, and stays quiet between those crossings. After the Low alert, the cycle starts again.

1

Waiting for High

Range Mode begins by waiting for a fresh reading above your High threshold.

2

One alert above High

After the High alert, Beat Watcher waits for a fresh reading below Low. It stays quiet between the thresholds, even if your heart rate rises above High again before reaching Low.

3

One alert below Low

After the Low alert, Range Mode starts waiting for High again.

For example, with High at 95 BPM and Low at 75 BPM, Beat Watcher alerts once when your heart rate rises to 96 BPM. It then stays quiet, even if your heart rate climbs above 95 BPM again, until it falls to 74 BPM and the Low alert arrives.

How it differs from ordinary alerts

With Range Mode off, High and Low alerts work independently, and Persistent Alerts can repeat feedback every few seconds while your heart rate stays past a threshold. Range Mode gives you one alert above High, then one alert below Low, in that order.

Turning it on

On Apple Watch, tap the top part of the Beat Watcher screen, tap Settings, then tap Range Mode. On iPhone, open Beat Watcher and tap Range Mode under Settings. Range Mode requires Alerts and Low Alerts to be on and Persistent Alerts to be off. Beat Watcher shows any required changes before turning it on.

Thresholds and resets

Change your High and Low thresholds on Apple Watch or in the Beat Watcher iPhone app. Every new monitoring session starts by waiting for High. To reset the cycle while Background Mode is active, turn Background Mode off, then turn it back on.

Requirements

Range Mode works in the foreground and in Background Mode and needs no separate purchase. It depends on fresh heart rate readings from Apple Watch, so reading gaps may delay alerts.

Heart rate can change for many reasons. Range Mode is for general wellness awareness. It does not determine recovery, readiness, or safety.

Choosing the right thresholds

The best thresholds depend on what you are using Beat Watcher for:

Medical monitoring

For POTS or ME/CFS pacing, consult your doctor. Common starting points are resting HR + 30 BPM for POTS, or (220 – age) × 0.6 for ME/CFS.

Stress awareness

For stress monitoring, set your high threshold 15–25 BPM above your resting heart rate.

Fitness and sauna

Set it to your target zone ceiling. For sauna sessions, 140 BPM is a common exit threshold.

Dual coverage

Set a high threshold of 120 BPM and a low threshold of 50 BPM to be alerted when your heart rate goes outside that range in either direction.

How it compares to Apple’s built-in notifications

Apple Watch has built-in high and low heart rate notifications, but they check periodically and are delayed. Beat Watcher provides:

  • Instant alerts with continuous monitoring in Background Mode
  • Fully customizable thresholds (any BPM you choose, vs. Apple’s preset options)
  • Persistent Alerts that repeat every few seconds while past threshold
  • Haptic + audio feedback directly on your wrist
  • Phone Alerts that forward threshold crossings to your iPhone, with Critical Alerts to cut through Do Not Disturb
  • Alert History on iPhone for reviewing alert events you save, with local notes, context tags, and CSV export of your saved history

Try Beat Watcher on your Apple Watch

Requires Apple Watch Series 4 or newer (watchOS 9+).

Download on the App Store
Beat Watcher on Apple Watch

Frequently Asked Questions

What range can the high threshold be set to?

The high threshold can be set from 30 to 250 BPM using the Digital Crown.

What range can Low Alerts be set to?

Low Alerts can be set from 30 to 150 BPM using the Digital Crown.

Can I use both high and low thresholds at the same time?

Yes. The high threshold and Low Alerts work simultaneously. For example, you might set your high threshold to 120 BPM and your low threshold to 50 BPM to be alerted when your heart rate goes outside that range.

What happens when my heart rate crosses a threshold?

Beat Watcher will provide haptic and audio feedback when your heart rate goes above or below the set threshold. If Persistent Alerts are enabled, the feedback repeats every few seconds as long as your heart rate remains past the threshold.

What is Range Mode?

Range Mode is an optional setting for fewer alerts while you monitor the range between your High and Low thresholds. Beat Watcher alerts once above High, then once below Low, and stays quiet between those crossings. After the Low alert, the cycle starts again.

How is this different from Apple Watch’s built-in notifications?

Apple Watch’s built-in heart rate notifications check periodically and are delayed. Beat Watcher provides instant alerts with fully customizable thresholds and works continuously in Background Mode. You can set the exact BPM level that matters to you.

Does the threshold persist after closing the app?

Yes. Your threshold is saved automatically and will be the same when you open Beat Watcher next time.

Related: Background Mode Guide · Phone Alerts Guide · Sleep Heart Rate Monitor · POTS Heart Rate Monitor