SEALs are mammals too; even they spend _some_ time on land. And, said in a less snarky way: I can see why a diving instructor would say "don't hold your breath

SEALs are mammals too; even they spend _some_ time on land. And, said in a less snarky way: I can see why a diving instructor would say "don't hold your breath" when you're under water. Navy SEALs likely dive a lot, but they also do training and actions above the water. And they likely spend a lot of time in stressful situations (certainly more than me). I can imagine they might box breath _on land_ to help manage the stress.