There are a few things that can help trumpet players avoid passing out from playing too high. First, they should make sure to warm up properly before playing. This will help to increase their lung capacity and reduce the risk of hyperventilation. Second, they should take breaks throughout their practice sessions to give their lungs a chance to rest. Finally, they should avoid playing in hot or humid environments, as this can make it more difficult to breathe.
If a trumpet player does start to feel lightheaded or faint, they should stop playing immediately and sit down. They should also take some deep breaths and try to relax. If they do not feel better after a few minutes, they should seek medical attention.