Asked by: Jason Woods, Dover
In all mammals, including humans, a dive reflex is activated when the face is submerged. The heart rate slows, and blood flow is diverted away from the limbs towards the head and torso. In aquatic mammals, this reflex is particularly well-developed. Without training, we can manage about 90 seconds underwater before needing to take a breath. But on 28 February 2016, Spain’s Aleix Segura Vendrell achieved the world record for breath-holding, with a time of 24 minutes. However, he breathed pure oxygen before immersion.