In this concise but dense talk drawn from his book Breath: The New Science of a Lost Art, journalist James Nestor argues that the human species has lost the ability to breathe correctly — and that the consequences are far broader than most people realise, touching on heart rate, digestion, brain function, immune response, and longevity. He offers five concrete, actionable techniques: switching from mouth to nasal breathing, actively maintaining lung capacity, slowing the breath (especially the exhale), correcting email apnea and chronic over-breathing, and building CO2 tolerance through breath retention. Each technique is grounded in pulmonology research, evolutionary biology, and ancient breathing practices.
Why Does Breathing Correctly Matter So Much?
Nestor opens with a deliberately provocative frame: "The only people who could benefit from breathing correctly are people who breathe." The joke lands, but the underlying point is serious. Breathing happens roughly 25,000 times a day, and each dysfunctional breath compounds across a lifetime. Nestor distinguishes between surviving and being genuinely healthy — a difference he describes as "compensation versus vibrant health." Mouth breathing, over-breathing, and shallow chest breathing are not acute emergencies; they are chronic low-grade stressors that gradually degrade cardiovascular, neurological, and immune function.
Tip 1: Stop Breathing Through Your Mouth
Nestor is unambiguous on this point: mouth breathing is, in his words, "terrible for our health." The nose is engineered for breathing in ways the mouth simply is not. It filters incoming air, heats it, pressurises it, and moistens it so that by the time air reaches the lungs, the body can extract roughly 20% more oxygen per breath compared with an equivalent mouth breath. That efficiency gain, compounded across tens of thousands of breaths a day, is enormous.
He points to the anatomy as evidence of intentional design: the front of the human face contains structures that, if removed, would leave a space equivalent to a billiard ball. These nasal passages force incoming air through a gauntlet of chambers where it is purified, conditioned, and pressurised. Nestor draws an analogy to sea animals that use their shells as a defence against invaders — the nose performs the same protective function for the respiratory system.
He also invokes comparative biology: of the 5,400 known mammal species, none are obligate mouth breathers except humans with obstructed airways. Dogs pant through their mouths only to offload heat — a thermoregulatory exception, not a breathing strategy. Chronic mouth breathing in humans is linked to periodontal disease, facial structural changes, hyperventilation, anxiety, and worsened allergies and asthma.
Tip 2: Improve Your Lung Capacity
Nestor references a large longitudinal study conducted approximately 40 years ago that tracked around 5,000 subjects and found that the single strongest predictor of longevity was neither genetics nor diet — it was lung capacity. The larger and more efficiently operating the lungs, the longer the individual tended to live.
The challenge is that lung capacity naturally begins to shrink after approximately age 35. Nestor's prescription is not aggressive respiratory training but rather consistent, low-intensity practice: breathing slowly and low (diaphragmatically rather than from the chest), maintaining good posture so the lungs can fully inflate and deflate, and doing even mild to moderate exercise regularly.
He also reclaims yoga as a breathing technology. The Vinyasa-flow yoga widely practised today was codified only about 100 years ago. The original practice was about sitting in a stable position and consciously controlling the breath — what Nestor calls "a technology of breathing." By maintaining flexibility in the thoracic area and practising controlled respiration, practitioners can preserve the lungs' full range of expansion across a lifetime.
Tip 3: Slow Down Your Breathing
Approximately 80% of the neural signals travelling between the brain and body originate in the body and travel upward, not the other way around. This means the physical act of breathing — its pace, depth, and rhythm — directly informs how the brain interprets the state of the body. Fast, shallow breathing sends an alarm signal: fight or flee. Slow, rhythmic breathing sends the opposite message: safety, calm, readiness to rest and digest.
Nestor's practical entry point is simple: inhale to a count of three and exhale to a count of six or eight. Extending the exhale beyond the inhale activates a parasympathetic response — measurable in reduced heart rate and blood pressure, and perceptible as a felt sense of relaxation throughout the body. He notes that this can be done anywhere, at any time, without equipment or training.
The physiological mechanism involves CO2 and oxygen balance. Slow breathing allows the body to use more of the oxygen already in the bloodstream rather than flushing it out with excessively rapid ventilation. This is why hyperventilation makes people feel dizzy or anxious: it lowers CO2 levels precipitously, paradoxically reducing oxygen delivery to tissues even as air intake increases.
Tip 4: Stop Over-Breathing and Correct Email Apnea
Nestor identifies two related dysfunctional patterns that affect a significant portion of the population. The first is chronic over-breathing — taking in more air than the body metabolically requires, keeping the nervous system in a low-level state of arousal and stress. The second is email apnea (or screen apnea): unconsciously holding the breath while reading or responding to email, then over-compensating with rapid, shallow breaths. He cites research suggesting this affects an estimated 80% of office workers.
The cycle looks like this: hold breath → become hypoxic and CO2-rich → take a rapid series of large breaths → repeat. Over time, this pattern resets the body's CO2 tolerance downward, making a person increasingly sensitive to even small rises in CO2, which the brain misinterprets as an emergency. The result is a hair-trigger stress response that becomes the default physiological baseline.
The corrective is awareness followed by deliberate slow nasal breathing, particularly during sedentary screen-based work. Nestor frames this not as a relaxation technique but as a basic maintenance practice — analogous to correcting a chronic bad posture before it causes structural damage.
Tip 5: Build CO2 Tolerance Through Breath Retention
The most counterintuitive of Nestor's five techniques involves deliberately holding the breath to build tolerance for carbon dioxide. The popular understanding of breathwork focuses almost entirely on oxygen — getting more of it. But Nestor argues that CO2 tolerance is equally important and largely overlooked.
CO2 is not merely a waste gas. It is the primary trigger that tells the body when to breathe, and it plays a critical role in the Bohr effect: the mechanism by which oxygen is released from haemoglobin into tissues. Without adequate CO2, oxygen clings to haemoglobin and is not efficiently offloaded to cells that need it. Paradoxically, breathing less — or holding the breath periodically — can improve cellular oxygenation by raising CO2 enough to drive oxygen delivery.
Nestor notes that by gradually increasing breath-hold tolerance over time, practitioners can shift their respiratory threshold — becoming calmer under physiological stress, performing better athletically, and entering states of focused attention more readily. This is the mechanism underlying many ancient pranayama practices and modern protocols such as the Buteyko method, even if the precise language differs.
How Breathing Connects to Every System in the Body
A thread running through all five tips is Nestor's insistence that breathing is not a narrow respiratory matter — it is a whole-system regulator. In his talk he lists the systems directly affected by how we breathe: heart rate, circulation, digestion, brain function, immune response, facial bone structure, and even spinal alignment. Dysfunctional breathing puts all of these systems under low-level chronic stress simultaneously.
He uses a simple self-experiment to make this visceral: try hyperventilating for 10 to 20 seconds and observe the result. The lightheadedness, tingling, and anxiety that follow are a compressed demonstration of what chronic over-breathing does, more slowly, across years.
"We want to breathe fewer breaths, but to obtain more oxygen in each breath. So that is efficiency. Why would we unnecessarily be overworking ourselves all day long?" — James Nestor
Where to Go from Here
Nestor's five techniques form a coherent hierarchy: close the mouth first, then protect and expand lung capacity, then slow the breath with an extended exhale, then audit and correct over-breathing and apnea patterns, and finally build CO2 tolerance through deliberate retention practice. Each step reinforces the others.
For those who want to go deeper, his book Breath: The New Science of a Lost Art draws on research in pulmonology, biochemistry, psychology, and human physiology, as well as Nestor's own experience as a subject in clinical breathing studies. Key practitioners and researchers referenced in the wider work include the Buteyko method tradition, the work of pulmonologist Dr. Breath (Carl Stough), and contemporary researchers studying nasal nitric oxide and the cardiovascular effects of resonant frequency breathing.
A practical starting point for today: tape your mouth shut lightly at night (a method Nestor himself used during a documented experiment) to enforce nasal breathing during sleep, where mouth breathing is both most common and most consequential. During the day, simply notice your breath pattern at the desk. Awareness consistently precedes change.
