High Pulse rate. It means your heart is beating faster than normal.
Pulse. One hypothesis is when breath rapidly it stimulates the baghdad nerves which stimulate the brain to produce more adrenaline which affects the blood vessels which increases pulse rate. Another theory is hyperventilation causes more demand for oxygen which makes heart work faster.
I have dysautonomia, all day today my heart rate is ~56bpm & I have been cold, my skin has red/purple spots. This is the opposite of my usual. Any advice on how to regulate and raise my pulse/ temp?
56=ok. There's nothing wrong with a heart rate of 56 - don't try to change it. I suggest you wear warmer clothing - it will make you more comfortable, probably will make the red/purple spots go away, is free/inexpensive, has no side effects, and won't interact with your other meds.
Autonomic lab. Try to find an autonomic lab that can test you.