According to the Internet (so it must be true), biathlon has its roots with Norwegian soldiers (i.e. good guys on military patrol). Yes, the modern-day biathlon event recreates the ancient battle of good vs. evil: only the strongest survives, and in this case, the best and most well-conditioned skier/shooter. Serious stuff, huh? It sort of puts "ice dancing" in its place, wouldn't you say?
Cross-country skiing is one of the best forms of exercise, and what really amazes me is a biathlete's ability to control his or her breathing for the moments when they have to be extremely calm/steady to hit small targets with their .22-caliber rifles. So their breathing is racing at near max level for the skiing, then they have to "shut it down" for the shots (five shots per stop), then it cranks up again for the skiing. And get this: If you miss targets, you have to ski farther (literally penalty laps), so it's mission-critical to be supremely accurate.
Check out this 28-second video clip, and be sure to crank up the volume as loud as possible. And simply listen to the shooter's breathing leading up to pulling the trigger, and then in between shots. Talk about calm at the moment of truth!
Whether your target is breathing or not, knowing when to hold it and when to ... um, exhale ... will improve your shooting significantly.