Some people hold their breath longer thanks to a mix of larger lung capacity, a strong diving reflex, a calmer response to the urge to breathe, and practice. Genes contribute too. In the Bajau people of Southeast Asia, researchers linked a gene variant to bigger spleens, which store extra oxygen-rich blood. For most of us, lung size, relaxation, and training make a noticeable difference as well.
What Limits How Long You Can Hold Your Breath?
When you stop breathing, sensors in your body track oxygen and carbon dioxide, and the urge to breathe grows stronger by the second. Eventually your diaphragm begins to contract involuntarily, an uncomfortable signal that most people cannot ignore.
Researchers have found that willpower and lung volume appear to matter more than how sensitive your chemical sensors are, although scientists are still working out the full picture.
Does Lung Size Make a Difference?
Probably, yes. In a study of 11 elite breath-hold athletes, forced vital capacity, a measure of how much air the lungs can move, explained nearly half of the differences in how long they could hold. A bigger starting supply of air buys time before discomfort takes over. The study was small, but it fits the common sense idea that a larger tank lasts longer. Lung size varies from person to person, which may be one reason some people start with an advantage.
What Is the Diving Reflex?
Humans share a built-in survival response with seals and whales. When your face meets cold water and you hold your breath, your heart rate slows, blood vessels in your limbs narrow, and your spleen contracts. That last step matters because the spleen releases a reserve of oxygen-rich red blood cells into your circulation, giving your body a small extra supply. Some people appear to have a stronger version of this response than others.
What Did Scientists Find in the Bajau?
The Bajau, often called sea nomads, live in Southeast Asia and spend much of their working day diving for food. In 2018, researchers reported that natural selection on a gene called PDE10A has increased spleen size in the Bajau, giving them a larger reservoir of oxygenated red blood cells. The team also found evidence of selection on BDKRB2, a gene that affects the human diving reflex. Their spleens were about 50 percent larger than those of a nearby non-diving group, and even Bajau who did not dive had larger spleens, which points to genes rather than training alone.
It is an exciting finding, but it comes with limits. The study looked at one population, and scientists are still working out exactly how the gene affects the spleen. It does not mean you can predict your own diving ability from a single gene.
Can Training Stretch Your Limit?
Practice helps a great deal. In one study, novices who completed two weeks of apnea training increased their breath-hold time by 46 percent. Part of that gain likely comes from learning to stay relaxed and getting comfortable with the urge to breathe. That is good news for anyone who feels shortchanged by their genes, because the mental side of breath-holding is largely trainable.
How Can You Practice Breath-Holding Safely?
Safety matters more than any record. Holding your breath in water can lead to shallow-water blackout, which means fainting underwater, and it usually strikes without warning and can happen in any body of water, even a bathtub. Experts advise never hyperventilating beforehand, never ignoring the urge to breathe, and never practicing alone. Dry-land practice with a partner nearby is the safest way to explore your limits. If you have a heart or lung condition, check with your doctor first.
Curious About Your Own Wiring?
A DNA report cannot tell you how long you could hold your breath, but it can help you explore how your genes relate to broader traits, such as endurance. SelfDecode turns your DNA data into personalized health recommendations, a handy starting point if you are curious. You might also enjoy our posts on the genetics of VO2 max and natural endurance and what your genes say about your muscle type.