Name: Nautilus
Rating: 5 (3 reviews)
Author: Ikee

Nautilus -- Apnea & Breath-Hold Training

Turn your Garmin into a dry-land breath-hold trainer. Record apnea cycles with live heart rate and best-effort pulse oximetry, follow CO2/O2 tables, or track a max hold. Save a FIT activity that syncs to Garmin Connect.

FEATURES
- Configurable countdown, vibration cues, progress ring and round indicator
- Live HR and available SpO2, hold statistics, session totals and comparison with the previous hold
- Four training modes: Basic, CO2 table, O2 table and Max hold
- Optional hold alerts, rest-ending warning, target cue and automatic end at target
- Plan pages preview every round's hold and rest, including final recovery
- Resume, Save or confirmed Discard; pausing preserves the current phase
- Garmin Connect SpO2 timeline, round laps, hold duration, minimum SpO2, longest hold and totals
- Optional tones, silent training and display wake at phase changes
- On-device settings and a built-in Controls guide

CONTROLS
Five-button watches: START/STOP begins or pauses; BACK/LAP ends a hold or starts the next hold during rest; UP/DOWN browse pages; hold UP for settings.

Touchscreens: tap the lower third for the BACK/LAP action, tap the top of the ready screen for settings, swipe up/down for pages and swipe right to pause. On two-button touch watches, the top button is START and the bottom is BACK/LAP. On vivoactive 3, the button starts/pauses, a lower-screen tap ends the hold and holding the screen opens the menu. Edge uses START and LAP keys; touch Edges page with a left/right swipe.

Find the same guide in Settings / Controls or by pressing DOWN on the ready screen.

TRAINING MODES
Basic: fixed countdown and rest, with unlimited rounds or a chosen round count and optional hold target.
CO2: hold time stays constant while rest gets shorter.
O2: hold target increases while rest stays fixed.
Max hold: one round; BACK/LAP ends the hold and opens the save menu.

SETTINGS
Adjust countdown, rest, rounds, hold targets, table steps, hold/rest alerts, vibration, tones, pulse oximetry and display wake. BACK/LAP during rest can start the next hold immediately or run its countdown. After saving, START begins a new session.

COMPATIBILITY
The app builds for 143 Garmin product targets running Connect IQ 3.0+: Descent Mk1/Mk2/Mk2i/Mk2S/Mk3/Mk3i/G1/G2, fenix 5 and newer, Chronos, epix, quatix, tactix, Forerunner, Instinct 2/3, Venu, vivoactive 3 and newer, Enduro, MARQ, D2, Approach, Edge and compatible handhelds.

Don't see your device under Compatible Devices? Garmin sells paid apps only to some devices. The free companion, Nautilus for classic devices, covers devices missing from this paid listing and runs the same app. Submitted for Garmin approval; installation will be available after approval:
https://apps.garmin.com/apps/f3f6abe7-7b56-46eb-b97a-5401c07689e2

Pulse ox needs Connect IQ 3.2 and a pulse-ox sensor. Unsupported devices show SpO2 as N/A. Garmin firmware controls reading availability and cadence; the app cannot force continuous measurement. Edge and handhelds need a paired heart-rate sensor and have no vibration motor; enable Tones for audible cues where supported. Devices without a speaker ignore Tones. G1 and Instinct layouts keep text clear of the circular display inset.

SAFETY
Dry training only. Train seated or lying down and do not train alone. Never use this app for in-water apnea. Wet apnea risks shallow-water blackout and requires a trained, attentive buddy at arm's length.

Permissions: Sensor, Fit and FitContributor.