In a feat that stretches the limits of human physiology, Croatian freediver Vitomir Maričić has set a new Guinness World Record by holding his breath for an astonishing 29 minutes and three seconds. The achievement, which took place in a 3-meter-deep pool in Croatia, has raised questions about the science behind such an extraordinary endurance.
While the average person can hold their breath for a mere 30 to 90 seconds, freedivers like Maričić have mastered the body’s involuntary reflexes to survive for minutes at a time. The key is to override the “breaking point”—the signal from the brain that tells the body it’s time to breathe. This signal is triggered not by a lack of oxygen, but by a buildup of carbon dioxide (CO2). By training, freedivers can desensitize their brains to this CO2 buildup and continue to hold their breath long after the urge to breathe becomes unbearable.
However, Maričić’s record-breaking attempt goes beyond mere training. This particular record is in the “oxygen-assisted” category, which means the diver breathes pure oxygen for a period before the attempt. This process, known as hyperventilation, flushes CO2 from the bloodstream and saturates the body with oxygen. According to Maričić, he began his dive with nearly five times more oxygen in his body than the average person. This “supercharged” state allows the body to delay the physiological breaking point, enabling a much longer breath-hold.
Even with this assistance, the feat is incredibly challenging and dangerous. The body’s “mammalian diving reflex” kicks in, slowing the heart rate (bradycardia) and redirecting blood from the extremities to vital organs like the heart and brain. However, as oxygen levels in the blood drop, a person is at risk of a hypoxic blackout, where the brain is deprived of oxygen and loses consciousness. For Maričić, the challenge was as much mental as it was physical. He stated, “It’s not about how much you inhale, it’s about how little you need. No panic, no thoughts, just silence. That’s how you make it to 29.”
Maričić’s world record, which he dedicated to raising awareness for ocean conservation, showcases a combination of extreme physical conditioning, mental discipline, and an understanding of the body’s innate survival mechanisms.
