Excessive caffeine has been linked to elevated heart rates, hypertension, anxiety, headaches, and interrupted sleep patterns.
Some energy drinks warn that they're not for use by individuals younger than 18, those pregnant or nursing, or if there's a family history of heart disease, high blood pressure, depression, caffeine-sensitivity, glaucoma, and other ailments. But most carry no warning.
A recent statewide Patient Poll conducted by the Pennsylvania Medical Society's Institute for Good Medicine found that 20 percent of respondents ages 21-30 had used energy drinks in high school or college to stay awake longer to study or write a paper.
Also the study found that 70 percent of respondents knew someone who had used an energy drink to stay awake longer to study or work.
A cup of brewed coffee has between 80 and 135 milligrams of caffeine.
Some energy drinks contain two to three times that amount plus the equivalent of 5 teaspoons of sugar.
"My colleagues and I are seeing more patients coming in with sleep disturbances, often caused by energy drinks," notes Philadelphia family physician and Chair of the Philadelphia Assembly, PA Academy of Family Physicians, Suzanne Steele, MD.
Dr. Steele feels that most people should not be drinking these beverages, especially growing children.
The expert said: "They can often be harmful. Energy drinks contribute to sleep disturbances, obesity, tooth decay, and dehydration. Children should be drinking milk instead to strengthen their growing bones.
"We're looking at a generation that will have serious problems with osteoporosis based on a lack of calcium intake and obesity from too much sugar."Brittle bones and too much weight on them just spells trouble."