The Drug in Your Nose

Of all the interventions in this collection, this is the only one that is free, always available, and something you are doing — badly or well — at this very moment. Functional breathing (through the nose, from the diaphragm, and often more slowly than feels natural) is the least glamorous and, arguably, the most powerful lever here. The catch is that most of us, most of the time, breathe in a way that quietly works against us.

The nose makes its own medicine

Start with a fact that ought to be more famous: your nose manufactures a drug. The paranasal sinuses continuously release nitric oxide — the same molecule that relaxes blood vessels, that won a Nobel Prize in 1998, and that inspired a certain well-known blue pill. When you breathe in through your nose, that nitric oxide is carried down into your lungs, where it widens the blood vessels around the air sacs and measurably improves the uptake of oxygen. Breathe through your mouth and you skip the dose entirely. The nose also filters, warms and humidifies the air; the mouth does none of these things. We have, in short, a superbly engineered breathing organ, and a worrying tendency to bypass it.

The man who half-suffocated himself

To prove how much this matters, the journalist James Nestor did something few would volunteer for. For his 2020 book on breathing, he had a Stanford rhinologist plug his nostrils with silicone for ten straight days, forcing him to breathe entirely through his mouth, while instruments tracked what happened. It was grim: he developed obstructive sleep apnoea, snored for hours a night, and his blood pressure climbed. When he switched back to nasal breathing — taping his mouth shut at night — the apnoea and snoring vanished, his blood pressure fell, and his heart-rate variability, a key marker of nervous-system balance, leapt by more than 150%. It remains one of the more vivid demonstrations in modern self-experimentation of a very old idea: how you breathe changes your physiology.

Slowing down, and the Iceman

Two threads of good science run through breathwork. The first is slow breathing: at around six breaths a minute, the heart and breath synchronise, the vagus nerve is stimulated, and the body shifts decisively toward its rest-and-recover mode — an effect shown to lower blood pressure and sharpen the reflexes that regulate it. The second is more dramatic. In 2014, researchers put a group trained in the Wim Hof method — a mix of forceful breathing, cold and focus — through an experiment in which they were injected with a bacterial toxin. Astonishingly, the trained group could voluntarily ramp up their own adrenaline and suppress their inflammatory response, cutting pro-inflammatory proteins by more than half and reporting far milder symptoms than untrained controls. It was the first proper demonstration that the innate immune response, long thought beyond conscious reach, could be deliberately influenced — through breathing.

You have breathed your whole life. You have, in all likelihood, been doing it wrong.

The most available lever there is

How to use it

The foundations are almost comically simple: breathe through your nose, day and night; let the belly, not the chest, do the moving; and when you want to settle the system, slow the breath toward six cycles a minute. More structured practices — the Wim Hof method, Buteyko, resonance breathing — layer on top for specific goals, some with real vigour and best learned with guidance. But the base of it all is that unfashionable instruction your grandmother might have given: close your mouth and breathe through your nose.