Meet Trevor Hutton, a South African freediver. Diving as deep as possible on one breath is a dangerous but exhilarating business, and in Deep Blue Dive we follow Trevor as he negotiates the hostile South African coastline, the ocean swells and dangerous marine life that inhabit his local waters. Trevor is self-trained but South Africa has always cautioned against the sport, and for good reason. But something incredible happens to this six-feet-plus man as he enters the water. We’ll watch as nerve receptors in his heart trigger oxygen-saving responses in his body, slowing his heart down by 50 per cent. Blood vessels constrict, his spleen shunts red blood cells into his bloodstream to prepare for a lack of oxygen and a litre of blood floods into the chest. His body turns into a deep diving machine. With CGI we’ll find out how Trevor’s extraordinary body uses subconscious techniques passed down genetically from generation to generation to cope in extreme conditions, and bring to life some of these incredible physiological transformations. And then there’s the beauty of the underground world off the coast of South Africa – deep blue and full of amazing marine wildlife.