Davina McCall: Life at the Extreme S01E02 - Azores - Deep

Davina travels to the Azores in the mid-Atlantic to investigate how animals cope with with atmospheric pressure changes underwater, particularly the ones that have to take in air before they submerge. She swims with a school of dolphins and finds out about the inbuilt response that both animals and humans have when they go underwater, and meets a world champion freediver who teaches her the techniques needed to swim alongside sperm whales, before trying to overcome her nerves and dive down to the ocean floor on a single breath.