Free‑diving, or breath‑hold diving, is a sport with historical ties to spear fishers and pearl divers. Most countries, including Canada, have national teams that compete to see who can dive the deepest and hold their breath the longest. Croatia’s national team continues to break world records and now some of their top divers are helping a team of Canadian researchers from UBC’s Okanagan campus.
School of Health and Exercise Sciences PhD candidate Chris Willie and a team of UBC scientists were invited to Croatia to work with that country’s top scientific lab in conducting tests on some elite free‑dive athletes. Among them was Croatia’s world‑record holder, Goran Colak, who recently held his breath for 22 minutes and 30 seconds after breathing in pure oxygen.
“There have been some preliminary studies done over the years on breath‑hold divers, but very little research completed on their brains,” says Willie, who is earning his PhD in cerebral vascular physiology. “We aim to tease out the mechanisms involved that allow these people to hold their breath for such a long time.” The second goal, he says, is to fundamentally understand how the brain responds to changes in blood gases, both oxygen and carbon dioxide.
Under dry land conditions in a lab, the athletes were monitored while holding their breath until reaching levels of oxygen far lower than most people could survive – nearly as low as that of a human on the summit of Mt. Everest. (The world record for free‑divers not using oxygen, the type of testing that Willie is conducting, is about 12 minutes.) Sophisticated ultrasound equipment was used to monitor the flow of blood into the brain.
“This kind of research is important to breath‑hold divers, and to most people,” Willie says. “But it’s especially important for people who live with diseases such as chronic obstructive pulmonary disease and heart failure, who have changes in blood flow that affect the delivery of oxygen to the brain. These are things that affect their pathology, their quality of life, and their doctor’s ability to treat them.”