I believe everyone has that shared experience of presenting and getting an instantaneous empty stomach or feeling butterflies flying everywhere. I have the exact same feeling and I have resorted to eating air as if its cheddar biscuits at Red Lobster. Weird but true taking long deep breaths has been essential in preparing for presentations. I read along time that as human beings we don’t breathe enough and often don’t give our bodies the air it needs. So if your fancy Fit Bit has an excellent tool to help you take deep control breaths through breathing in when the circle closes and out when the circle closes. But, if that doesn’t work start by taking breaths in waiting to your chest fills completely you can tell its filled when you fill pressure inside. Another cool tricked I learned through swimming is breathing with mouth open and then exhaling with your nose, easy stuff right. So the next time your getting ready to present and you get an emptiness in your stomach take a breath and you will feel a lot better.