It’s the time of year when getting fit tops many resolution lists. But reaching for that energy drink to get you prepped for exercise may do more harm than good, according to research presented last month at the Radiological Society of North America’s annual meeting. [1]
Researchers at the meeting explained their findings that the hearts of adults have shorter contraction times one hour after consuming energy drinks containing caffeine and the amino acid taurine. The research did not include sports drinks designed to replenish lost nutrients and electrolytes during exercise.
Jonas Dörner, M.D., of the University of Bonn, Germany, explained how his colleagues compared the contractions of the heart using MRIs before consuming energy drinks and an hour afterward. They found that the lower left chamber of the heart – the left ventricle – contracted more vigorously in people who drank energy drinks. Heart rate, blood pressure and the amount of blood leaving the heart, though, remained about the same within one hour of consumption, the research concluded.
What the Results Mean
Those shorter contraction times may disrupt the normal function of the heart, according to Jonathan Fialkow, M.D. [2], medical director of clinical cardiology at Baptist Cardiac & Vascular Institute [3] and certified lipidologist. He says the main concern is that over time, and with higher doses of caffeine consumed with multiple servings of the drinks, those shortened heart contractions may lead to scarring of the heart muscle, and increased risk for higher blood pressure and potentially life-threatening arrhythmias.
Dangers to Young People
“This study just looked at the short-term effects of consuming one of these drinks,” Dr. Fialkow said. “We know from what we see in the Emergency Room that people, especially teens and young adults, generally consume two or three of these drinks in a short period of time.”
The effects of energy drinks on adolescent’s hearts were not part of this study, but the Substance Abuse and Mental Health Services Administration (SAMHSA), in a January 2013 report [4], suggested these products were originally marketed to 18- to 25-year-olds, and that age group dominates trips to the emergency room following consumption of these drinks. That same report cites increased use among people 40 years of age and older between 2007 and 2011.
The Caffeine Culprit
Most of the reported dangers of energy drinks, including the SAMHSA report, point to excessive caffeine – a fact disputed by the American Beverage Association [5]– a trade organization representing non-alcoholic beverage makers in the United States. The Association issued a response [6]to the Radiological Society of North America’s research: “The fact remains that most mainstream energy drinks contain only about half the caffeine of a similar size cup of coffeehouse coffee. Caffeine is a safe ingredient and is consumed every day in a wide variety of foods and beverages, including energy drinks, which have been enjoyed safely by millions of people for nearly three decades.”
Dr. Fialkow agrees that most of the energy drinks contain the same amount of caffeine as is found in coffeehouse servings, but adds that consuming two or three coffeehouse servings is less likely than consuming two or three energy drinks. Plus, he says, people drink larger amounts of energy drinks at one time.
“Younger people typically don’t consume coffee for various reasons – cost, taste, etc. – and adults are more likely to stop drinking coffee before too much caffeine is consumed,” Dr. Fialkow said.
Combining Energy Drinks with Alcohol
There’s also the trend of combining energy drinks with alcohol, which Dr. Fialkow says contributes to a quicker absorption of the alcohol that masks the symptoms of being drunk. This could lead to more alcohol consumption in a shorter period of time, increasing the risks for alcohol poisoning, drunk driving and other life-threatening dangers.
Sports Drinks
Dr. Fialkow says that while there are concerns in the medical community that caffeine-based energy drinks can be dangerous, sports drinks do serve a purpose for hardcore athletes.
“While sports drinks contain minerals and fluids that should be replenished after periods of intense sweating, they also contain a lot of sugar to improve the taste. That sugar can contribute to weight gain, just as we see with soft drinks, and adds no benefit to the intensity of a workout,” he said. “For most people who exercise for short bouts with moderate intensity, water is the best drink to prevent dehydration.”
For children, the recommendation is the same. The American Academy of Pediatrics, in a 2011 article [7] published in its journal Pediatrics, suggested water is the best first choice for hydration for most activities, as long as a person maintains a healthy daily caloric and nutrient intake. However, those who participate in prolonged or vigorous activity, the article said, may also need to replenish their carbohydrate levels, and sports drinks fulfill that need.
More Studies Needed
Dr. Fialkow says the real value of this latest study of energy drinks is that it will likely lead to more studies that will test the long-term effects of consuming these beverages.
Dr. Dörner, who presented the study at last month’s meeting, hinted that more studies are on the horizon.
“We’ve shown that energy drink consumption has a short-term impact on cardiac contractility,” he said. “Further studies are needed to evaluate the impact of long-term energy drink consumption and the effect of such drinks on individuals with heart disease.”
In the meantime, Dr. Fialkow hopes people understand the possible risks posed by consuming excessive amounts of caffeine through energy drinks. Those risks may outweigh the desired benefits, he warns, and those benefits are extremely minimal.
“We simply don’t yet know the long-term effects on our bodies. It’s best to drink these products in moderation or avoid them altogether,” he said.