The average human can hold their breath between 30 to 90 seconds before needing to take a breath. You can increase this time with practice, and by taking slow, calm breaths prior to a breath hold, rather than hyperventilating.
If we're swimming underwater, your time holding your breath may be much lower! On 27 March 2021, Croatia’s Budimir Šobat achieved the world record for breath-holding underwater, with a time of 24 minutes and 37 seconds. However, he breathed pure oxygen before immersion.
Yet there is one group of sea-faring nomadic people called the Bajau who habitually spend minutes at a time underwater, at depths of up to 60 metres. They have lived on the waters off Southeast Asia for more than 1,000 years, and collect their food by freediving, without snorkels, fins or wetsuits.
While they practise and train to perfect their skills, research published in the journal Cell in 2018 found that the Bajau actually have physiological adaptations to help them dive better. A key difference was that they have a DNA mutation for an enlarged spleen. In fact, the spleen was found to be up to 50 per cent larger in Bajau individuals, compared to a related group of people called the Salua, who live on the mainland.
The spleen stores and filters blood, removing any damaged red blood cells, meaning that a larger spleen would provide a greater reservoir of oxygenated red blood cells.
How can I hold my breath for longer?
For people who want to increase the amount of time that they can hold their breath, it is obviously safest to practise on land, from the comfort of your home. Take slow, calm breaths prior to a breath hold, rather than hyperventilating by breathing quickly in and out. As you hold your breath, try to relax your body and think of other things.
Once you’re ready to attempt breath holds in water, try just submerging yourself in a swimming pool while holding onto the side.
If you are keen to approach the three-, four-, or even five-minute mark for holding your breath underwater, then there are courses run by freediving schools, where you can be trained to improve your skills in a safe environment.
Read more about breathing:
- Does holding your breath make you stronger?
- Mouth-breathing: Why it's bad for you and how to stop
- Dr Michael Mosley: How deep breathing can soothe anxiety, help you sleep and more
How long can marine mammals hold their breath?
In all mammals, including humans, a dive reflex is activated when the face is submerged into cold water. The heart rate slows, and blood flow is diverted away from the limbs towards the head and torso, where essential organs like the brain and heart are located. These physiological changes allow us to survive for longer when we are submerged in water.
In marine mammals, this reflex is particularly well-developed, and has become an adaptation for their aquatic lifestyle, allowing them to hunt, play and even sleep underwater.
The world record for the mammal that can hold its breath for the longest is the Cuvier’s beaked whale, with one individual completing a dive lasting 222 minutes. Other marine mammals can also remain submerged for impressive periods of time, with sperm whales habitually clocking up 90-minute dives, and harbour seals managing 30 minutes.
Aquatic mammals are so good at surviving underwater because their muscles are chockful of myoglobin. In fact, myoglobin in the muscles of marine mammals can exceed those of land-based mammals by a factor of 30.
Myoglobin is similar to its cousin, haemoglobin, in that it contains iron and can store oxygen. However, myoglobin has a greater affinity for oxygen and is less affected by acidity than haemoglobin. This is important, because during long dives, carbon dioxide and lactic acid build up in the muscles, making them more acidic.
As well as this, marine mammals have streamlined, torpedo-like bodies, meaning they don’t need to put in much effort when swimming, so their oxygen stores last for longer.
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