Samantha

There is real literature on slow breathing and digestive function, but it doesn't test this exact protocol. A study by Tak et al. (2016, Neurogastroenterology & Motility, n=18) did show increased gastroduodenal motility with slow breathing at a 4-second inhale / 6-second exhale pace — but combined with transcutaneous auricular vagus nerve stimulation, not breathing alone. A vagal-biofeedback trial for functional dyspepsia (n=40) showed improved symptoms and quality of life with breathing exercises at 6 breaths per minute — but without a measurable increase in baseline vagal tone, which actually undercuts the 'it works via the vagus nerve' explanation. A study on rumination syndrome points the same way: diaphragmatic breathing reduced episodes, but that improvement wasn't correlated with a measured rise in vagal tone. None of these studies test 8-second box breathing specifically, and none confirm the direct link 'box breathing to better digestion' claimed here. Verdict: unproven — the idea that slow breathing helps some digestive symptoms has real ground, but this exact protocol and mechanism aren't what the available studies show.