Johanna is performing deep breathing exercises, she is sitting on the edge of a foreboding triangular hole, freshly cut into the surface of a remote frozen lake in Southern Finland, she is about to dive. Join us on a journey of discovery about the science of risk. Inigo is partnering with Johanna Nordblad, a record-holding professional Ice water freediver, to understand how she is able to de-risk the seemingly foolhardy,
transforming it into something exceptionally calculated and executed. We will learn about the science that keeps her safe. From the technical aspects of understanding the environment she operates in, to the complex physiological reactions she has to stimulate and control to achieve what she does. Her perspective on risk is breathtakingly similar to ours.
Let’s jump in.
THE VAGUS NERVE
A nerve no thicker than a single human hair is the critical communication channel between Johanna’s brain and vital organs. Her ability to stimulate this nerve allows her to control her heart rate within very strict parameters.
Her heart rate slows down significantly, sometimes by as much as 50 percent or more. This reduction in heart rate helps her conserve oxygen and allows her body to maintain a steady supply of blood to vital organs.
As a response to the increased pressure underwater, blood is shifted from her extremities towards her chest cavity and vital organs. This redistribution of blood helps to maintain the blood pressure and oxygen supply to her essential organs.
Her spleen, an organ located in the upper left side of the abdomen, contracts in response to the dive reflex. This contraction releases additional red blood cells into her circulation, further optimising oxygen-carrying capacity.
If the ice suddenly breaks under foot as she is traversing a frozen lake, Johanna carries ice daggers tethered to her wrists as a safety precaution. They might be the only chance she has of preventing herself going under.
Johanna uses a brightly coloured guide rope under the ice. The danger of disorientation is high. Losing her way back to the ice hole could end in catastrophe.