Well the other day I bought a tub of the powerade powder mix so I could bring a sports drink with me on some rides and not spend a fortune. I used it in 3 bottles so far on the MTB with lots of drinking of water from the camel back. Well today I headed out on the road with one bottle decently flavored and one with what I thought to be more water for earlier in the ride. I was only taking a small drink every mile or two which is typical of me. However when I got to mile 19 my chest started to hurt. It hurt when I was breathing, and hurt right behind my sternum. I have never had this happen to me before, I have been out of breath before but not this. I had not recently taken on any major hills and every other part of my body was fine.

My only theory as to why this could have happened was maybe I used too much powder in the bottle? Does this seem reasonable or any other suggestions?

I rode my MTB yesterday for 4 solid hours of some pretty tough climbs and stellar downhills and pysically I was drained but even then I was not out of breath...

???

Sounds like lung cancer to me.

maybe the powerade is giving you heartburn....or GERD

High carbohydrate, concentrated sports drinks can contribute to gastroesophageal reflux. It doesn't necessarily mean GERD; many athletes experience GER training (esp. high intensity) though it is more common for runners than cyclists. It's less common with water. It's one reason I stick to gels and blocks and solid food. I use electrolyte water as well, though it doesn't contain sodium. I still have a hard time with the blocks in my throat / chest if I eat when my HR is too high.

I had the same problem with Cytomax.