Listen to this deep hum (a tectonic rumble, a 95 Hz drone, ~6 Hz theta binaural pulses) to "activate" your vagus nerve and shift into a parasympathetic state that makes falling asleep easier.

noli's read

Same picture as with isochronic tones: systematic reviews of binaural beats and brainwave entrainment find mixed, heterogeneous results (Ingendoh et al., PLOS ONE, 2023; 8 of 14 studies contradict the entrainment hypothesis). The "vagus nerve stimulation" language isn't backed by the same evidence as actual vagal stimulation (electrical, or the slow-breathing route documented by Zaccaro et al.) — listening to a low hum doesn't mechanically stimulate the vagus nerve in the physiological sense, even though the subjective effect (a feeling of calm, easier sleep onset) can be genuinely real for the listener. Low, continuous brown-noise-type sound is reasonably associated with easier sleep onset in the noise-and-sleep literature, more through a sound-masking effect than any specific vagal mechanism. No measurement of cortisol, heart-rate variability, or vagal activity accompanies this video — only a technical description of the audio mix. Verdict: unproven — a plausible soundscape for winding down, but the "vagus nerve" mechanism it claims isn't what would explain the effect, if there is one.

the sources

No named source held this one up — that absence is part of the verdict.