High energy drinks such as Red Bull, Rockstar, and Monster have become wildly popular during the past decade with the greatest consumption by teens and young adults. While they have been touted as helping to increase athletic performance, they are primarily used by older teens and college students as a study aid and sleep substitute. Teens and young adults have very busy lives with classes, sports, after school activities, and jobs. This grinding schedule generally leaves little time for studying. As a result, this age group has turned more and more to the use of highly caffeinated drinks, usually in place of a good night's sleep.
As a result of several scientific studies, scientists have issued warnings about the use of highly caffeinated drinks and have gone so far as to recommend that the FDA require warning labels on cans of high energy drinks. The FDA currently regulates the amount of caffeine allowed in soft drinks to 71 mgs per 12 ounce can but since energy drinks are labeled as "dietary supplements", there is no legal limit to the amount of caffeine they can contain.
The energy drink No Fear contains 174 mg of caffeine and Monster and RockStar each have 160 mg. That means as little as two cans of each of these drinks (more than 250 mgs) can induce "caffeine intoxication" which, according to the Diagnostic and Statistical Manual of Mental Disorders, can cause restlessness, nervousness, excitement, insomnia, flushing of the face, increased urination, gastrointestinal disturbance, muscle twitching, a rambling flow of thought and speech, irritability, irregular or rapid heartbeat, and psychomotor agitation. Larger doses can cause mania, depression, lapses in judgment, disorientation, disinhibition, delusions, hallucinations, and psychosis. Large amounts of caffeine, in some cases, can induce anxiety severe enough to require medical attention. The British Journal of Addiction concluded that "caffeinism," although infrequently diagnosed, may afflict as many as one person in ten of the population.
There's not a whole lot of information on the risks of high energy drinks and driving but it doesn't take a huge stretch of the imagination to make a correlation between the symptoms listed above and the dangerous effect they can have on driving.
Moderate use of caffeine, say in one or two cups of coffee, has certainly been shown to have a beneficial effect in raising alertness and can be quite effective in keeping a driver awake and alert on the road. The problems occur when large amounts of caffeine cause a driver to become excited, irritable, nervous, and restless. It is well known that irritable, agitated drivers become aggressive drivers. Rambling thoughts and mental agitation can cause a driver to take chances that he or she might not otherwise take and loss of patience and anger can lead to poor decision making which can be deadly on the road.
The biggest problems occur when these high energy drinks are used as a substitution for sleep. Lack of sleep along with the large doses of caffeine can increase the level of agitation and, instead of raising the alertness level, can cause a driver to become disoriented. Studies show that approximately one hour after drinking a highly caffeinated and sugared drink, a sleep deprived person can experience lapses in concentration and tends to have slower reactions. The greatest danger comes when the effects of the caffeine wear off. At that point, a sleep deprived driver won't be able to fight the fatigue and can very quickly fall asleep at the wheel. It has long been recognized that sleepy drivers have the same reaction time and driving skills as someone who is legally drunk. Long term use of these high energy drinks can also lead to "caffeine induced sleep disorder" which disrupts the user's sleep patterns leading to even more sleep deprivation.
Large amounts of caffeine can also cause increased heart rate and blood pressure. Anyone with heart problems or a family history of heart problems should cut back on their consumption before it leads to a heart attack. For a person who normally ingests large amounts of caffeine, withdrawal can cause problems too. While it is obviously beneficial for people to cut back on their use of caffeine they should be aware that withdrawal symptoms can include severe headaches and difficulty concentrating. Driving should be avoided while you are trying to withdraw from caffeine.