Pneo is a breath training app built around CO2 tolerance, the physiological base of calm, steady breathing. Instead of only guiding you through a session, Pneo measures where you are and trains you to breathe less and hold longer over time.

WHAT YOU CAN DO

CO2 Tolerance Test
Measure your CO2 tolerance with a guided test and get a score you can track and share. Your score is a simple readout of how well your body tolerates carbon dioxide, which is what actually drives the urge to breathe.

Guided breathing techniques
Practice box breathing, extended exhales, coherent breathing, and more, with a clear on-screen circle, phase counts, and optional sound and vibration cues.

CO2 training tools
Build tolerance with structured CO2 tables and drills, calibrated to your current level.

Learn library
Short, readable lessons on how breathing works: CO2 and the Bohr effect, the nervous system, the vagus nerve, and why slower breathing changes how you feel. Sources are cited.

Progress tracking
See your scores and practice history over time, all stored on your device.

PNEO PRO
Pro unlocks Personalized CO2 Training calibrated to your level, a 4-week progressive program, and advanced analytics. Pro is available as a monthly or annual subscription with a 3-day free trial, or a one-time lifetime purchase.

WHO IT IS FOR
Anyone who wants calmer, more controlled breathing: for stress, focus, sleep, athletic performance, or freediving practice.

Pneo is an education and training tool. It is not a medical device and does not diagnose or treat any condition. If you have a heart or respiratory condition, are pregnant, or have any concern, talk to a clinician before starting breath holds.