What is Breath Holds?

2006

Finding: This study of competitive breath-hold divers examined why hyperventilating before a hold is dangerous: taking rapid deep breaths beforehand blunts the natural, carbon-dioxide-driven urge to breathe, so the body can run critically low on oxygen before any warning signal arrives, leading to fainting (a hypoxic blackout) or loss of muscle control. The researchers noted that even trained competitors performing maximal holds surfaced with these hypoxia symptoms, and that prior heavy exercise can lower the oxygen level at which trouble begins. For anyone practising breath holds, the practical message is clear: never hyperventilate to stretch a hold, avoid pushing to your absolute limit, and never do holds in or near water, where a blackout can be fatal. This work focuses on the specific setting of breath-hold diving and static apnea, so it speaks most directly to prolonged or maximal holds rather than brief, gentle pauses.

2018

Finding: This physiology review tracked what happens inside the body during maximal breath holds in highly trained apneists, and found that holding the breath sets off a coordinated "diving response": the heart slows, blood vessels in the limbs tighten, and the spleen contracts, all of which stretch the body's oxygen supply, while blood flow to the brain climbs by roughly double its resting level to keep the brain supplied. For someone practising breath holds, this shows that even a simple pause in breathing engages a built-in reflex that shifts the nervous system toward conserving oxygen. The measurements here come from elite competitive divers pushing to their limits, so the dramatic changes described are not a goal for everyday practice; a gentle hold engages the same reflex far more mildly.

n = 40

Finding: In this trial, 40 healthy adults preparing to climb to 5,100 metres either practised voluntary breath holds on their own for six weeks or did not, and the training worked as intended for one thing: average longest breath-hold times rose from about 80 seconds to 107 seconds. But that new capacity did not carry over to the mountain, roughly the same share of people in each group developed altitude sickness (42% versus 52%), and the breath-hold group fared no better on anxiety, sleep, blood-oxygen levels, heart rate, or blood pressure at altitude. For someone considering breath holds as altitude prep, the takeaway is honest and specific: you can reliably extend how long you hold your breath, but this study gives no reason to expect that alone to ease altitude symptoms or calm nerves. Because the trial was small and limited to healthy adults on a single high-altitude ascent, it speaks to that scenario rather than to breath holds as a general wellness practice.

n = 1,263

Finding: Across 22 studies of 1,263 adults, this review found that how long someone can comfortably hold their breath is a useful window into how well they tolerate uncomfortable body sensations: people with anxiety disorders held their breath for shorter times than those without, with the clearest, moderate difference showing up in panic disorder. Breath-hold time also rose and fell with in-the-moment anxiety and distress, though it was only weakly tied to a person's general, longer-standing anxiety levels. For someone exploring breath holds, this suggests the practice touches the same body-awareness and discomfort-tolerance that anxiety can shrink, but the study measured breath-holding as a marker of that tolerance, not as a treatment, so it does not show that breath-hold training treats or resolves anxiety or panic.

2021

Finding: This review looked at breath-holding as it's actually been studied, which is mostly in elite competitive divers and apneists pushing toward maximal, extreme holds, not in everyday people doing gentle, graded breath work. Its main takeaway is a caution: the long-term health effects of regular breath-holding aren't established, designing an effective protocol is trickier than it sounds, and firm claims about breath holds as a performance tool still await proper placebo-controlled trials. For someone considering the practice, this means the dramatic results seen in trained divers shouldn't be read as proven benefits of light or moderate holds; the evidence for the kind of practice most people would do is still thin.

2025

Finding: This review of breath-holding in sport found that repeated holds can briefly raise markers that help the blood carry oxygen, and that people who practise over the long term tend to tolerate the uncomfortable "air hunger" better and show some cardiorespiratory and muscle adaptations. For a practitioner, that points to breath holds as a way to build comfort with the urge to breathe rather than a proven performance booster, since the authors are clear that the evidence is not yet strong and needs properly controlled trials. It is also worth knowing that most of this research looks at elite divers doing extreme maximal holds, so how well it applies to gentle, everyday graded practice is still an open question.

2009

Finding: Tracking eight elite divers through maximal breath holds, this study found that the involuntary breathing movements of the late "struggle" phase, along with tightening blood vessels in the limbs and rising carbon dioxide, worked together to keep blood volume, and oxygen, flowing to the brain even as the hold pushed toward its limit. In practical terms, the uncomfortable urge to breathe that builds near the end of a hold is part of how the body protects the brain, not simply a signal that something is going wrong. This was a small snapshot of highly trained specialists during extreme holds, so it describes the body's built-in reflexes rather than a target for everyday practice; the deep drops in oxygen these divers reach are not a goal to chase.

2004

Finding: Studies of breath-hold divers found that hyperventilating before a hold, or pushing to a long or deep maximal hold, can drop blood oxygen low enough to cause fainting and loss of muscle control, sometimes without warning. The research also showed that a long bout of exercise beforehand delays the natural urge to breathe, letting oxygen fall further before your body signals you to stop, which raises the risk of blacking out. For anyone practising breath holds, the practical message is clear: never hold your breath in or near water, and don't over-breathe to stretch your holds, since a blackout can be silent and, in water, fatal. This evidence comes from divers and swimmers specifically, so it speaks most directly to holds done at the edge of your limits rather than gentle, seated pauses.

1994

Finding: When elite breath-hold divers breathed air enriched with carbon dioxide, they kept breathing far more slowly and steadily than untrained people, showing they were less driven to gasp for air as CO2 climbed. In practical terms, regular breath-hold training seems to build tolerance for the rising carbon dioxide that creates the urge to breathe, which is likely why experienced practitioners can stay calm and hold longer before that panicky "air hunger" kicks in. The key limit is that this was measured in highly trained divers rather than everyday people following graded light-to-strong holds, so it points to what practice may develop over time rather than proving what any single beginner routine will do.

2012

Finding: This study of breath-hold divers found that hyperventilating before a hold, and pushing to long or maximal holds, can drop blood oxygen low enough to cause fainting and loss of muscle control before the urge to breathe ever kicks in; a hard bout of exercise beforehand makes this even more likely. For anyone practising breath holds, the practical takeaway is clear: never hold your breath in or near water, and don't over-breathe first to stretch the time, because the warning signs may not arrive until you've already blacked out. Keep in mind that this evidence comes from elite divers doing extreme holds rather than everyday people doing gentle, graded practice, so it speaks far more to what's risky at the extremes than to the effects of moderate, comfortable holds.

n = 13

Finding: In a small experiment with 13 healthy adults, resting in water up to the neck let people hold their breath about 20% longer than usual, and the carbon dioxide that normally builds up during a hold rose more slowly, a sign the body was storing more of it. That extra CO2 storage did not actually line up with who held their breath longest, so the study couldn't pin down exactly why immersion stretches a hold. For a practitioner, it's a useful hint that your surroundings and how your body handles CO2 can change how long a breath hold feels doable, but the underlying mechanism here remains an open question.

2016

Finding: This small study followed 16 competitive divers through three days of a national breath-hold competition, comparing them against five people of similar age who didn't dive, and tracked blood markers linked to brain-cell stress to see whether repeated extreme breath-holding leaves a measurable mark on the nervous system. It's worth knowing this looked at elite athletes pushing apnea to its competitive limits, which is very different from the gentle, short breath holds most people use in a calming practice. Because the group was small and drawn only from top-level divers, it can't tell you much about everyday breathwork, but it points to a sensible caution: the safety picture around long, maximal breath-holds is still being worked out, so building holds gradually and never near water alone is the prudent approach.

2014

Finding: This small study compared eight elite breath-hold divers with scuba divers and non-divers, and found that the breath-hold divers responded much more calmly to rising carbon dioxide: when breathing air enriched with extra CO2, they breathed noticeably less hard than untrained people did. In practical terms, their bodies had learned to tolerate more of the CO2 buildup that normally triggers the urgent "I need to breathe" feeling, which is the same air hunger you meet during a breath hold. For someone practising breath holds, this points to a real physiological reason the urge to breathe can become easier to sit with over time. Keep in mind the finding comes from a handful of highly trained divers rather than beginners following a light-to-strong practice routine, so it shows what is possible with extensive training more than what any given protocol guarantees.

2013

Finding: When trained breath-hold divers and untrained people breathed air with extra carbon dioxide added, the divers breathed noticeably less in response, meaning their bodies reacted less strongly to the rising CO2 that normally triggers the urge to breathe. For someone practising breath holds, this points to a real physiological reason why regular practice can make you more comfortable with the "air hunger" that builds during a hold, rather than that feeling being pure willpower. Keep in mind this was measured in elite divers, not in everyday light-to-strong breath-hold routines, so it shows what long-term adaptation can look like rather than proving that a beginner's graded practice produces the same change.

n = 9

Finding: When nine experienced breath-hold divers pushed themselves to a maximal breath hold, using the intense pre-breathing and air-packing techniques they rely on in training and competition, a protein that shows up in the blood when the brain is under strain (S100B) rose measurably afterward. In plain terms, holding your breath to the extreme limit appears to place real stress on the brain, not just the lungs. This was a very small study of just nine highly trained divers performing competition-style maximal holds, so it speaks to the far edge of the practice rather than the gentle, comfortable breath holds most people would use, and it is a caution worth respecting before chasing longer and longer times.

n = 11

Finding: In 11 trained male freedivers holding their breath as long as they possibly could, the brain's ability to keep its blood flow steady was temporarily weakened, and that dip tracked closely with rising carbon dioxide rather than falling oxygen. In practical terms, it is the build-up of CO2 during very long, maximal holds, not simply running low on oxygen, that briefly loosens the brain's blood-flow control, which is a good reason to build up hold times gradually rather than pushing to your absolute limit. This was a small snapshot in a handful of highly trained divers, so it says nothing about the shorter, gentler holds most people practise, and it is not evidence that graded breath work causes harm.