In waltz we use breathing (only in training, not at comps) , to 1 breath out but dont lose your streched spiral & frame and breath in to 2 but dont raise shoulders and get stiff.

My partners never recognice that my breathing frequency raise during dancing, but i dont control it, i recognice my breathing when leaving the floor, when we prepeare our frame for the next dance its gone again...
I take a look at my trainers the last day and they do it the same, too. During dancing you dont see them breathing. But after a dance .... 
I was in a hurry so i cant speak with them about this topic...
In germany, some of the high level couples of each county get special trainings, one or two times a mounth. During this , like all common athlets, (we are artist
) they get (sorry, I dont know the correct words in english) sport specific medical care, how to raise condition, what to eat ... ,how to prepeare for comps....
During one of these sessions some guys of an for athlets specialized medical care center come and measure that data. The data was analyzed and they told us something about our condition and give us hints how to perform better on heats at comps. And may be they use this data for other things we dont know
.
BTW, the best thing was the masseur, i liked it but then he was replaced by a psychatrist... before a comp he talk to us that we are sooooo good...
since dancer have a totally different performance profile like "normal" athlets its different to prepeare. A dancer have to give all between the 1 1/2 minutes of dance... every second on the floor count.. 5 times 1 1/2 minute full power ...so we was instructed that dancers have to train very different like 100m or marathon runners. its more like running 1000m 5 times with a break of a minute. so it is OK that the heartbeat is about 180 to 220 after a dance. But during the break it must go down under 100 or 110. At comps we have to dance up to 5 heats including the final (35-40 couples).In training we do final heats, 1 1/2 dancing, 1 minute break, again and again and again. after a little warming up phase 5 final heats with full power and heartbeat have to be under 110 after a break. If heartbeat hangs at 130, the couple was out and have train this extra as homework.