And now for something completely different. We hold our breath and go underwater with Tetsuo Hara, champion free diver. Tetsuo is a tech executive  by day and in his free time, an elite freediver. He set a Guinness World Record by reaching 100 meters in constant weight at age 58. He explains why deep dives are won with preparation, calm, and systems thinking, not bravado.
• Constant weight freediving basics and what 113 meters feels like under pressure 
• How an engineering mindset turns the body into a trainable system 
• The real drivers of performance like CO2 tolerance, equalization, relaxation, and lung flexibility 
• Training progression that builds confidence by going shallow first 
• Why the urge to breathe is mostly CO2 and how training delays the reflex 
• Close calls, abort decisions, and the safety logic that keeps divers alive 
• Ideal deep dive conditions including warmth, visibility, low current, and free fall 
• Pre-competition food and hydration choices plus why scuba holds no appeal 
• Lessons from the sport on consistency, community and facing yourself