Most people can hold their breath underwater for a minute or two, but a people called the Bajau can spend up to five hours a day underwater, diving to depths that would unnerve a scuba diver — and scientists have traced the ability to a change written into their very DNA

If you don’t believe in any kind of human evolution, I present to you this story about bajau people who have adapted because they live near the sea, and spend a lot of time under the water … their bodies can maintain their oxygen supply for much longer than most humans, go deeper than you and I, and they have a unique ability to recover quickly once they return to the surface; they can dive again almost immediately. 

https://spacedaily.com/d-most-people-can-hold-their-breath-underwater-for-a-minute-or-two-but-a-people-called-the-bajau-can-spend-up-to-five-hours-a-day-underwater-diving-to-depths-that-would-unnerve-a-scuba-diver/