Statistics show that adolescents are the fastest-growing population of caffeine users.

A new study published in the Journal of Nutrition Education and Behavior, as reported by Medical News Today, indicates that 83.2% of teenagers consume caffeinated beverages regularly, and at least 96% consume them occasionally.

How much caffeine is safe? The Mayo Clinic states that up to 400 mg of caffeine a day is probably safe for most healthy adults. That is approximately four cups of brewed coffee, 10 cans of cola or two “energy shot” drinks.

More than 500-600 mg a day, they term “heavy daily caffeine use.” Heavy use can cause side effects, such as nervousness, anxiety, jitteriness, sleep problems, gastrointestinal disturbances, tremors, increased heart rate and even death.

Even moderate doses of 100-400 mg can cause symptoms in children and adolescents.