The fastest way to increase lung capacity in Grand Theft Auto: San Andreas is to keep CJ (the main character) underwater for as long as possible. Lung capacity increases with time spent underwater.
Avoid swimming because it drains breath and leads to less time spent underwater. Lung capacity is one of many attributes that can develop depending on how CJ is used. CJ can gain muscle mass by working out, which helps in fist fights. Fat can be gained by eating often and lost by running. It's good to have a small amount of fat to burn when running or else muscle will be lost. Skills can be developed with weapons by using specific guns to damage a target. Improvements in weapon skills lead to increased aim, range and damage. Driving and flying increases skills in those areas and lead to more control of cars and planes.
Lung capacity is considered one of the less important skills in the game because it is only necessary for one mission. Grand Theft Auto: San Andreas has an open world environment that allows players to explore the environment and begin missions at any time. It was the first game in the Grand Theft Auto series to allow swimming. In previous games, characters would drown after coming into contact with water.