I have an odd issue when I raise my heart rate quickly (or at the beginning of exercise). It doesn t persist, it s only when I initially get my heart rate up, typically in a quick manner (for instance if I jump on a pull up bar and knock out a set of pullups, then do some dips, etc). This happens nearly everyday - I get an odd sensation in my stomach(?) - maybe more in my chest, but it eventually moves into the base of my throat, like an odd tickle, but there s definitely an odd sensation in my stomach / chest (hard to pinpoint the location). Then my mouth starts to create saliva at a very high rate, so high that I can lean over a sink and saliva will just continue to drip from my mouth (it forms under my tongue / the bottom of my mouth). This usually lasts about 30 - 60 seconds. After that I m good to go and I m able to exercise vigorously (brazilian jiu jitsu for upwards of 90 minutes). Any idea what the hell is going on when I initially bring my heart rate up?