I have an interesting quandary for you to consider. I live in an area of the southeastern US that becomes EXTREMELY humid during the summer months as well as during other times throughout the year, and as I'm sure you're aware of, there is a proportional increase in HR as relative humidity percentage increases. In other words, when it's 85% humidity and even just 85 degrees, you can really feel your heart practically beating out of your chest even during a slower-paced run. In fact, the left side of my chest will actually be sore during the last half mile or so of my run when the climate is that humid. Sometimes I will even get the feeling that death must be imminent and that I won't possibly be able to make it another mile back to my car. This is drenched-in-sweat humidity, where you get so sweaty after 30-40 minutes that your running shoes squeak when you walk in them.So which do you think would make for a more dangerous workout that would be more likely to lead to having a heart attack and/or cause a greater increase in HR: not taking any stimulants and running in extreme humidity, or taking EC and running in a dry, tolerable climate?