Holding your breath: what happens and when not to

What happens while you're not breathing

Your body keeps working: it uses up oxygen and makes carbon dioxide, which builds up in your blood because it has nowhere to go. After a while the urge to breathe shows up, faint at first and then impossible to ignore. The moment your body forces a breath is called the breakpoint.

It's usually explained with carbon dioxide alone, and rising carbon dioxide does push you to breathe. But a review by Michael Parkes, published in 2006 in Experimental Physiology, concludes that there is no simple explanation. Neither blood gases nor lung size account for it on their own, and the author suggests the diaphragm plays a bigger part than once thought. The same review makes two useful points. How long a hold lasts varies enormously from person to person and with how much air you start with. And under normal conditions, nobody can hold their breath until they pass out: an involuntary mechanism steps in.

The diving reflex

Hold your breath with your face wet and cold, and your body answers with a reflex you share with every air-breathing vertebrate studied so far. The trigeminal nerve senses water on your face and the vagus nerve slows your heart: in humans, heart rate drops 10 to 25 percent. Blood vessels in the arms and legs narrow, and blood is saved for the core organs. It's an adaptation for conserving oxygen underwater. It is not a reason to practice breath holds there.

The danger: hyperventilating, then holding

That safety mechanism has a weak spot. If you breathe fast and deep before a hold, you blow off a lot of carbon dioxide and add almost no oxygen. With carbon dioxide low, the urge to breathe arrives late, and oxygen can fall to the point of blackout with no warning from your body. In water this is called freediving blackout, or shallow-water blackout when it happens near the surface, and it ends in drowning.

The U.S. Centers for Disease Control and Prevention (CDC) reviewed 16 cases in New York State between 1988 and 2011. Four people died. Half were advanced swimmers, and every case of intentional hyperventilation involved an advanced swimmer.

Something similar happens on land. A 2014 study measured healthy young men doing rounds of thirty full breaths followed by an empty-lung hold of two to three minutes. Their blood oxygen saturation dropped to around 50 percent for about ten seconds in each round. That's why these practices are done sitting or lying down, and never in water.

What tradition says

In yoga, the hold is called kumbhaka, from a word meaning pot. It can be done with the lungs full or empty, and the hatha yoga manuals treat it as the heart of pranayama. Those same texts are cautious. The 15th-century Hatha Yoga Pradipika asks you to progress little by little, the way a lion, an elephant or a tiger is tamed, and says practice done wrong brings on illness.

The pauses on this site

Nearly all of them are short. Box breathing 4-4-4-4 holds for 4 seconds full and 4 seconds empty. Triangle breathing 4-4-4 and 4-4-8 breathing hold for 4 seconds. 4-7-8 breathing holds for 7. At that scale, the pause is a moment of stillness.

Two breathings carry a high-intensity notice. The 1-4-2 ratio holds for 16 seconds in every cycle. Deep breathing rounds pair thirty full breaths with an empty-lung pause whose counter runs to 60, 90 and 120 seconds: that's a ceiling, not a goal.

There isn't much research on what the pauses themselves add. A 2023 trial of 108 adults included a box breathing group and a group doing fast breaths with a 15-second hold. Every group reported better mood, and so did the group that meditated. The trial can't tell us how much of the effect belongs to the pause.

When not to hold your breath

• In or near water. Not the pool, the ocean, the bathtub or the shower. Ever.
• While driving or running any machinery.
• Standing up, if the hold is long or follows fast breathing. Fainting on your feet means a fall.
• As a contest, with yourself or anyone else. The clock isn't the point.
• Without asking a health professional first if you're pregnant or have a heart, lung or blood pressure condition, epilepsy, or a history of fainting or panic attacks.
• When your body says enough. Dizziness, tingling, blurred vision, a pounding heart or a headache are signals to let the air go and breathe normally.

How to do it sensibly

A good hold feels like waiting, not fighting. Your throat, face and shoulders stay loose. You don't bear down, and you don't fill up to the brim.

Your exhale tells you whether you overdid it: if you can let the air out slowly and evenly, the pause was the right size. If it bursts out or you need to gasp, it was too long. Lengthen over weeks, not days, and only once the current pause is easy. Long holds are for experienced adults and, when possible, for learning with a teacher.