I would also like the preach the benefits of deep breathing, only from a different perspective.

As a person with severe asthma et al, deep breathing has saved me from many a trip to the hospital, or at least long nights of albuterol induced insomnia. Especially when i'm crying (imagine that, i'm also a guy), or hyperventilating. It helps if you have a person there (or on the phone) to coach you through it, bascially just counting your breathing off for you, or breathing loud enough to be heard over your own gasps. It gets very hard to focus on much of anything when the fullest breath you can get is about an 1/4-1/8 of normal. Panic is a keyword. It feels like your mind is numb, and about to pass out. But either way, it helps stop the randomness of your breathing, and stabilize your mind