Contrary to popular belief, caffeine does not cause stress. Normally, minor stresses occur during the course of most people's routine day. For those who drink caffeine beverages, especially in large quantities, stress levels are quick to rise and slow to subside. Caffeine inhibits the body's normal biochemical turn off mechanism for stress responses. As stresses continue to occur, the accumulation of stress responses without relief intensifies stress symptoms.
Dehydration is another potential problem with excessive caffeine consumption.
This is especially true for those who use coffee, colas or teas as their primary beverage. Since caffeine is a diuretic and acts to increase fluid loss via urine output, these beverages are a poor substitute for water. Mild dehydration can increase fatigue, further intensifying the perceived need for more caffeine. And, thus the cycle continues. Cardiac Arrthymias can also be intensified and prolonged by caffeine's effect on the body.