Lots of energy drinks contain large amount of vitamin B that causes heart palpitations and tremors. Fitness enthusiasts should be aware that caffeine has a strong diuretic effect. This means that energy drinks should not be consumed after a workout since the body loses a lot of liquid during physical activity. The body can become extremely dehydrated and go into shock.
Overdose can lead to a sharp pressure increase or blood sugar levels increase. People suffering from heart disease and hypertension should not drink them at all. Countries such as France, Denmark and Norway have banned energy drink sales in grocery stores and other commerical stores; drug-stores are the only places you can purchase the drinks in those countries.