The following 1 min audio tracks can be used to find a breathing rate that increases parasympathetic activity, “recovery breathing”. The breathing pattern can help you recover energy quickly, even within a couple of minutes, without having to take a long rest.
The tracks are filtered white noise. Listen to the audio and inhale as the sound gets louder and exhale as the sound gets softer. The exhalation will be slightly longer than the inhalation as that increases parasympathetic activation. Use the audio as a rough guide. You do not need to stress about breathing exactly in time with it every breath.
Find a breathing rate that is comfortable. If you are using the HRV Trace app then look for a wave pattern on the display as you breathe with the audio. The slowest rate that feels comfortable and that gives a smooth wave pattern will be your recovery breathing pace.
You can listen to these audio tracks here, or you can download them by right-clicking on the link and selecting the “Download linked file” option.
Some people find that their most comfortable breathing rate is between the ones listed above. Here some additional tracks to try.