Yes, there's very good research that longer exhalations activate the parasympathetic nervous system.

I'd be interested to see if Dr. Huberman's method (breathing pursed lips through the mouth) is more effective, or if it's just the longer exhalation.

I teach this using "ujayi" breathing - keeping the throat muscles slightly closed when exhaling. It seems to have similar effects though I haven't seen research comparing the two.

By the way, I've written Resperate numerous times regarding their $300+ breathing device. They only recently admitted they've done no research comparing it to doing the same (in their case, long slow breathing with the same length for inhale and exhale - 15', 4x a week) without any device.

My guess is it's the same (their claims to lower blood pressure with their device alone were recently subjected to further research (previous research confirmed the claims) and they didn't reach a level beyond placebo.

People don't exercise, eat terrible quality food, are stressed out, hardly sleep, smoke, drink alcohol, etc and expect a simple breathing exercise (or a pill!) to lower blood pressure.

I can't guarantee doing the best things will eliminate your need for blood pressure meds (It hasn't in my case, but it least it keeps it anywhere from 10-20 points lower than it otherwise would be).

Anyway, I'll keep trying different breathing methods - maybe I CAN get off the pills one day:>)