This is what raises blood pressure, depletes muscle and organ hydration…

Health supplement for sportsmen -- Glycerine increases blood volume, enhances temperature regulation and improves exercise performance in the heat, or so it is claimed. It helps "hyperhydrate" the body by increasing blood volume levels and helping to delay dehydration. Following glycerol consumption, heart rate and body core temperature are lower during exercise in the heat, suggesting an ergogenic (performance enhancing) effect. In long duration activities, a larger supply of stored water may lead to a delay in dehydration and exhaustion. However, read the safety provisos.
http://www.supplementwatch.com/supatoz/
supplement.asp?supplementId=152