The challenge in sport freediving is that humans can destroy their own limits. By hold breath, and can dive back into the water for a long time and so far. Experience the sea is calm. for divers who can dive deeper to have a peaceful mind and concentration For divers who can dive too deep than 100 meters, heart rate is reduced, rest just 20 times per minute. From the usual 60 times per minute. However sports freediving it is considered a dangerous sport.