Alternatives
Products that do what O2 - Breath Hold Trainer does
Train your breath holds with science-based apnea tables
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Turn your watch into a complete breath training system.
Jun 2026 · apps-developer.garmin.com
- 4IM
Hey HN! Some more info: I’m an NHS doctor and the founder of Pi-A (https://www.pi-a.io) which developed Lungy (https://www.lungy.app). Lungy is an app (iOS only for now) that responds to breathing in real-time and was designed to make breathing exercises more engaging and beneficial to do. It hopefully has many aspects of interest to the HN community – real-time fluid, cloth and soft body sims running on the phone’s GPU. My background is as a junior surgical trainee and I started building Lungy in 2020 during the first COVID lockdown in London. During COVID, there were…
2023 · lungy.app
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- 6BP
2020 · github.com
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Through controlled breathing it is possible to regulate your body's stress response. I've built an app to measure and train this effect with a Polar H10 Heart Rate monitor. With every breath you take, you can set the pace of your breathing rate, measure your breathing control with the chest accelerometer, and see how heart rate variability responds.
2023 · github.com
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- 11IM
Hey HN! I’m an NHS doctor and the founder of Pia (https://www.piahealth.co) which developed Lungy (https://www.lungy.app). Lungy is an iOS app that responds to breathing in real-time and was designed to make breathing exercises more engaging and beneficial to do. It’s been two years since Lungy launched (here’s the original ShowHN: https://news.ycombinator.com/item?id=34534615) and it's had a huge update and complete redesign. We rebuilt the whole app, and added a real-time 3D soft body solver which gives some really cool interactions like blobs /…
2025 · apps.apple.com
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I built a terminal app that paces slow breathing at 6 breaths per minute for vagal tone training. It's a single Python file, stdlib only, no dependencies — just run breathe and follow the bar. I'm a cardiology patient (HFrEF). Slow breathing at resonance frequency is one of the few non-pharmacological interventions shown to improve cardiac vagal tone and baroreflex sensitivity (Bernardi et al., Circulation 2002; Lancet 1998). I wanted a frictionless daily habit tool — no app store, no account, no subscription, just open terminal and go. Design constraints, all grounded in the clinical…
May 2026 · github.com
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Not AI-powered. Built for my wife. Simple & Science-backed.
2025
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CO₂ tables, breathwork & dive log for freedivers 49 chars
May 2026 · fathomfreedive.app
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- 22DT
A person's heart rate fluctuates based on factors such as activity, environment, and mental state. Additionally, heart rate variations occur on a much shorter timescale, with changes happening every few seconds. During inhalation, heart rate slightly increases, and it decreases again during exhalation, a phenomenon known as respiratory sinus arrhythmia. There are several reasons for this. Firstly, an increase in volume within the thoracic cavity (the space between the ribs) leads to a corresponding drop in pressure, which is counteracted by a rise in heart rate to regulate blood pressure.…
2023 · github.com
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- 24BT
2020 · breathing.tips
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