# Apnea Trainer

> Apnea Trainer is a breath-hold training app for iPhone, Apple Watch and Android, built and maintained since 2010. The site also publishes science-based guides on CO2 tolerance, dry apnea training and freediving, each one tied to named, linked studies. The blog exists to check the folklore of breath-hold training against what has actually been measured.

## About

- [About this blog](https://apnea-trainer.com/about-this-blog/): Who writes the Apnea Trainer blog, why it exists, and how every claim is tied to a source. Written by a keen amateur freediver who has built and maintained the app since 2010.
- [App Store](https://apps.apple.com/app/apnea-trainer/id391269557): Apnea Trainer for iPhone and Apple Watch.
- [Google Play](https://play.google.com/store/apps/details?id=de.appbisweb.apneatrainer&hl=en): Apnea Trainer for Android.

## Articles (English)

- [Breath Training for Runners: CO₂ Tolerance for More Endurance (An Honest Guide)](https://apnea-trainer.com/blog/breath-training-for-runners/): Breath work is a lever on CO₂ tolerance, breathing economy and comfort — not on your VO₂max ceiling. What the runner studies really show, plus a dry protocol.
- [The BOLT Score: What This CO₂ Tolerance Test Really Tells You (and What It Doesn't)](https://apnea-trainer.com/blog/bolt-score-co2-tolerance-test/): A myth-check of the BOLT score: a genuinely useful personal signal of CO₂ tolerance — but not the validated performance predictor the "40-second ideal" makes it sound like.
- [Find Your Breath-Hold Baseline: A Free Interactive Test (No Water Needed)](https://apnea-trainer.com/blog/breath-hold-baseline-test/): Before you train, measure. A guided dry test — paced breathing, one relaxed max hold — and an honest reading of what your result means.
- [Kumbhaka: What Yogic Breath Retention and Freediving Have in Common](https://apnea-trainer.com/blog/kumbhaka-breath-retention-freediving/): Pranayama’s retention and a freediver’s CO₂ table are the same mechanism in different vocabularies. What holds up under measurement — and what does not.
- [Breath-Hold Training for Spearfishing: A Beginner's Dry-Training Plan](https://apnea-trainer.com/blog/breath-hold-training-spearfishing/): You need less bottom time than you think — and CO₂ tolerance, not lung volume, is what is holding it back. A full six-week dry plan.
- [Apnea Walks: The Dry CO₂ Training You Can Do Anywhere](https://apnea-trainer.com/blog/apnea-walks-dry-co2-training/): Movement makes CO₂ faster. Apnea walks turn that into the most time-efficient dry tolerance session there is — with a configurable interval timer.
- [What Science Says About Breath-Hold Training: 4 Studies in Plain English](https://apnea-trainer.com/blog/breath-hold-training-science/): Four peer-reviewed studies, no hype: what breath-hold training actually changes, how fast, and which popular claims the measurements refuse to back.
- [CO₂ Tables Explained: The Science of Training Your Urge to Breathe](https://apnea-trainer.com/blog/co2-tables-explained/): The urge to breathe is a CO₂ alarm, not an oxygen alarm. Here is how CO₂ tables train that alarm — and how to build one from your current max.

## Artikel (Deutsch)

- [Atemtraining für Läufer: CO₂-Toleranz für mehr Ausdauer (ehrlich erklärt)](https://apnea-trainer.com/de/blog/atemtraining-fuer-laeufer/): Atemarbeit ist ein Hebel auf CO₂-Toleranz, Atemökonomie und Komfort – nicht auf deine VO₂max-Obergrenze. Was die Läufer-Studien wirklich zeigen, plus ein Trocken-Protokoll.
- [Der BOLT-Score: Was dieser CO₂-Toleranz-Test wirklich verrät (und was nicht)](https://apnea-trainer.com/de/blog/bolt-score-co2-toleranz-test/): Ein Myth-Check des BOLT-Scores: ein wirklich brauchbares persönliches Signal für deine CO₂-Toleranz – aber kein geprüfter Leistungsindikator, wie es das „40-Sekunden-Ideal" verspricht.
- [Baseline-Test: Wie lange kannst du die Luft anhalten? (kostenlos, ohne Wasser)](https://apnea-trainer.com/de/blog/atemanhalte-baseline-test/): Vor dem Training kommt die Messung. Geführter Trocken-Test mit Atem-Pacer und Stoppuhr – plus Einordnung, was deine Zahl wirklich bedeutet.
- [Kumbhaka: Was yogisches Atemanhalten und Freediving gemeinsam haben](https://apnea-trainer.com/de/blog/kumbhaka-atemanhalten-pranayama/): Die Retention im Pranayama und die CO₂-Tabelle beim Freediving sind derselbe Mechanismus in zwei Sprachen. Was der Messung standhält – und was nicht.
- [Atemtraining fürs Speerfischen: Ein 6-Wochen-Trockenplan für Einsteiger](https://apnea-trainer.com/de/blog/atemtraining-speerfischen/): Du brauchst weniger Bottom Time als gedacht – und CO₂-Toleranz statt Lungenvolumen bremst dich. Ein vollständiger 6-Wochen-Trockenplan.
- [Apnea Walk: CO₂-Trockentraining, das überall funktioniert](https://apnea-trainer.com/de/blog/apnea-walk-trockentraining/): Bewegung produziert CO₂ schneller. Der Apnea Walk macht daraus die zeiteffizienteste Trockeneinheit überhaupt – inklusive konfigurierbarem Intervalltimer.
- [Was die Wissenschaft zum Apnoetraining sagt: 4 Studien verständlich erklärt](https://apnea-trainer.com/de/blog/apnoetraining-studienlage/): Vier peer-reviewte Studien ohne Marketing: Was Apnoetraining wirklich verändert, wie schnell – und welche populären Claims die Messungen nicht hergeben.
- [CO₂-Tabellen erklärt: Die Wissenschaft hinter dem Atemreiz](https://apnea-trainer.com/de/blog/co2-toleranz-tabellen-erklaert/): Der Atemreiz ist ein CO₂-Alarm, jedoch kein Sauerstoff-Alarm. So trainieren CO₂-Tabellen genau diesen Alarm – inklusive Generator für deine eigene Tabelle.

## Notes

- German articles are written natively, not machine-translated; each one is the counterpart of an English article, linked via hreflang.
- Every article cites the journal, year and a link to the abstract. Claims that cannot be sourced are not published.
- Nothing on this site is medical advice. Breath-hold training carries real risk, especially in water.