Swim for a long time, often. Train, push, and work at it.
long distance jogging, cycle, swimming
As well as great exercise,you can build stamina and endurance for both long and short events
Swimming.
One of the best ways to build endurance is to run on the beach. A lot of marathon runners prepare by running on the beach in the sand. It will help you build endurance.
Endurance - NikkiJ.
swimming & shooting
Running, jogging and swimming are all good for building endurance. You just keep at it on a regular basis, ideally two or three sessions a week, and try and go a little further each time.
practice
It helps build up physical endurance and strength
Holding your breath without any reason is actually bad for the body. If you are performing any activity, swimming for instance, holding your breath for long time will work for your benefit. To build good endurance regular physical exercise is advisable.
probably swimming
Endurance