[perow1]

Well, there are people who don´t get them. There are also people who don´t get them from not holding their breath long enough AND most importantly people who hyperventilate and dont get them.

People who hyperventilate will not get a good breathhold and most importantly will be doing a dangerous thing and risk their health/life.

Don´t let the contractions be a measurement of your breathhold capacity. How your body react is very individual and is to be learned together with someone else with experience. Be safe.