Thanks for the suggestion - sounds a lot like hyperventilating - will try. It can be embarrassing when it happens in a meeting, so sometimes I forewarn the speaker(s)!
There is lack of oxygen in your lungs. Do this exercise to exhale the old air in your lungs and so increase the oxygen level.
Build up your timing gradually.If you feel tired or dizzy, stop and resume after one minute.
Kapalbhati - Push air forcefully out through the nose about once per second. Stomach will itself go in(contract in). The breathing in(through the nose) will happen automatically. Establish a rhythm and do for 30 to 100 times.
Not for pregnant women. Seriously ill people do it gently. If you do this for more than one minute, then do it before eating or on empty stomach.