The nose-plugging experiment, and what a study of two people is good for

Two men had their noses plugged for ten days at Stanford, and the results became the centrepiece of a bestselling book. A study that size cannot prove anything. It is still worth your time, and the controlled version of it, run forty years earlier, is more interesting than either.

In 2020 a science journalist and a Swedish breathing instructor had silicone plugs pushed into their noses and taped over, and left them there for ten days. Then they spent ten days breathing through the nose only. Jayakar Nayak, a rhinologist at Stanford, ran the measurements. The journalist was James Nestor, and the account of it is the centrepiece of his book Breath.

The numbers he reported are the ones people remember. On the first obstructed night his sleep apnea events went up fourfold and his snoring rose by something like 1,300%. His blood pressure climbed about 13 points, which put him into stage one hypertension. Heart rate variability fell and stress hormones rose. When the plugs came out and the nasal phase started, the snoring collapsed, the apnea events went to nothing, and his blood pressure settled roughly 10 points lower than it had been.

It is a vivid story, and it is two people.

What a study of two cannot tell you

There was no control group and no blinding. Both men knew exactly which phase they were in, both expected a direction, and both had an obvious interest in the result being dramatic. With two subjects there is no meaningful statistics to run, and no way to separate the effect of blocked noses from the effect of ten days of knowing your nose is blocked. It was never published in a peer-reviewed journal.

To his credit Nestor says most of this himself, in print and in interviews, and describes the experiment as not conclusive evidence of anything. That is a more honest framing than the book usually gets credited with, and more honest than most people manage about their own results.

What a study of two can tell you

Self-experiments have a real history, and dismissing the form is lazier than the form itself. Barry Marshall drank a culture of Helicobacter pylori in 1984 to show it could cause gastritis, which it promptly did, and he shared a Nobel Prize for it in 2005. An n of one or two is not useless. It is just answering a narrower question than people think.

What it can establish is that something is possible, and roughly what it looks like when it happens. Blocking a healthy person's nose can produce snoring and apneas within a single night. That is a real claim and this experiment supports it.

What it cannot establish is how often, in whom, or how much. Those are the questions a reader actually has, and no self-experiment answers them.

It had been done before, properly

This is the part that makes the experiment more interesting rather than less, and it is usually left out.

In 1981, Olsen, Kern and Westbrook took eight healthy adults and studied each of them across two nights, one with the nose open and one with it obstructed. With the nose blocked, sleep was measurably disturbed: more awakenings, more stage shifts, longer REM latency, more time in light sleep, and significantly more partial and total obstructive breathing events. One of the eight developed sleep apnea from the acute obstruction alone.

In 1984, Lavie and Rubin did something cleverer. They blocked the noses of six men who had no apnea themselves but whose fathers did, and compared them against four age-matched men with no family history. Occlusion raised the number of apneas far more in the sons than in the controls. The same blocked nose did substantially different things to different people, and the authors read it as an inherited tendency toward unstable breathing in sleep that nasal resistance then exposes.

So the Stanford experiment was a vivid re-staging, forty years on and with better instruments, of a finding that already had controlled evidence behind it. That is a reasonable thing for a journalist to do. The honest description is that it illustrates a real effect rather than discovering one, and illustration has value.

The result that complicates all of it

Here is where it gets genuinely interesting.

If blocking the nose causes apneas, unblocking it should cure them. A systematic review of eleven studies of surgical and non-surgical treatments for nasal obstruction, each with sleep studies before and after, found mostly no relationship between nasal obstruction and the apnea-hypopnea index. Reducing nasal resistance did not reliably improve obstructive sleep apnea.

Both things appear to be true at once. Acutely blocking a nose generates breathing events. Unblocking a chronically obstructed one does not reliably remove them. The authors raise the possibility that the effect shows up in sleep fragmentation and arousals rather than in the apnea count, and note that few of the studies measured those.

The sensible reading is that the nose is a load on the system rather than the disease itself. A blocked nose makes a night worse. Clearing it does not, by itself, fix a breathing disorder that has other causes.

Before you tape your mouth shut

This is the point where the book sends people to the chemist, so it is worth being direct.

A 2025 systematic review in PLOS ONE pulled together the ten studies that exist on mouth taping, about 213 patients in total. Every one of the ten was rated poor quality. Only two found a significant reduction in the apnea-hypopnea index, and both were in people with mild obstructive sleep apnea only. Four of the ten warned that sealing the mouth carries a risk of asphyxiation or regurgitation in anyone whose nose is not clear, and most of them had excluded people with nasal obstruction from the start, which means the evidence barely applies to the people most likely to reach for tape.

The authors' own words are that there is a potentially serious risk of harm for people practising this indiscriminately. If you snore heavily, gasp or stop breathing at night, or have never been assessed for sleep apnea, the thing to do is get assessed, not to tape your mouth and hope.

That assessment matters here for a reason beyond sleep. Untreated sleep apnea presents as exhaustion, flat mood, poor concentration and irritability, which is also what depression looks like from the outside, and people are treated for the second while carrying the first for years.

What to take from it

The experiment is good journalism and weak evidence, and those are not in conflict. It made a forty-year-old finding legible to people who were never going to read Acta Otolaryngologica, and the finding it dramatised is real.

Breathing through your nose is better than breathing through your mouth, and you do not need a study to act on that one, because the cost of trying it while awake is zero. The leap worth resisting is the one from there to a protocol, a product, or a claim that your nose is the reason you feel the way you do. The controlled evidence says a blocked nose makes a night worse. It does not say clearing it will make you well.

This article is for general information and is not a substitute for professional care. If you are in crisis or thinking about harming yourself, please contact your local emergency services or a crisis line. See crisis lines.