Show HN: Sixbpm – a free thing that slows your breathing down
A free web app called Sixbpm uses a phone's accelerometer to detect breathing, then plays tones guiding the user to slow their breathing to about six breaths per minute over 15 minutes. The technique, based on public-domain research into resonance frequency breathing, is intended to lower heart rate and activate the parasympathetic nervous system. No account, ads, or data collection is involved.