Energy drinks and life-threatening heart rhythm problems: the mounting evidence

When a 17 year-old girl, with a potentially life-threatening heart disorder, recently presented to me with an abnormally fast and irregular heart rhythm, I wondered how the natural history of her disease could so abruptly lead to a potentially fatal electrical rhythm disturbance. Until I questioned her more about the moments leading to the rhythm problem. Uncharacteristically, she had consumed a significant volume of a popular energy drink. Within an hour, she was in hospital receiving electrical shocks to her heart to bring her heart back into a normal rhythm. A mere co-incidence, or did consuming an “energy drink” trigger her potentially fatal heart rhythm?

Energy drink consumption has grown exponentially over the last 5-10 years.  Energy drink sales are increasing at double the rate of total carbonated beverage sales [1]. Energy drinks are primarily targeted at the vulnerable youth and young adult market with aggressive advertising and marketing, and the potential medical complications of ingesting such drinks are becoming more and more apparent, both to cardiologists, as well as other health specialists.

So what is in energy drinks which could potentially trigger cardiac events? Energy drinks typically comprise of high levels of caffeine, guarana, taurine and sugar with various other amino acids often also included. The combined levels of caffeine in these energy drinks are much higher than a standard cup of coffee [2,3]. Adverse events and complications from energy drinks largely arise from their caffeine content. Furthermore, energy drinks are targeted to be drunk fast, and more recently, have ben condensed to smaller volumes, so called “energy shots”, freely available in petrol stations and other convenience stores.

So what are the medical effects of energy drinks? Based on currently available peer-reviewed scientific literature, there are many effects. From a cardiac perspective, there are three main effects, i.e. an increase in heart rate, an increase in blood pressure, and evidence of increasing blood viscosity that can lead to clots forming in the heart and beyond. Most recently, 3 independent cases have been described in the medical literature where consumption of energy drinks led to catastrophic consequences, including cardiac rhythm disturbances and cardiac arrest. [4-6]. In addition, many other non-cardiac effects of energy drinks have been reported, including anxiety, insomnia, vomiting, nervousness and irritability. As well as this, many young adults combine high-energy drinks with alcohol or physical activity, which can further exacerbate the potential risks of the active ingredients.

These three recent cases further highlight the potential detrimental cardiac effects of energy drink consumption, particularly in those who may be predisposed to arrhythmias due to an underlying genetic heart disease. Given the potential catastrophic consequences of energy drink consumption amongst susceptible young individuals, greater community education and awareness needs to be promoted. This may include somewhat more drastic measures, including more graphic and clear warnings on energy drink cans to warn people of the potential dangers, much like the highly successful packaging of cigarette cartons which include images of the consequences of smoking such as cancer. Another key initiative may be to restrict the sales of energy drinks to children and adolescents, often the target of current energy drink advertising and under significant peer influence. The collective goal of such measures is to prevent the incidence of potentially life-threatening cardiac rhythm problems, particularly in the young, by raising awareness in the community of the potential detrimental effects of energy drinks.


[1] AC Nielsen. Nielsen Convenience Report, 2010.

[2] Gunja N, Brown JA. Energy Drinks: health risks and toxicity. Med J Aust 2012; 196: 46-9.

[3] Higgins JP, Tuttle TD, Higgins CL. Energy Beverages: Content and Safety. Mayo Clin Proc. 2010; 85: 1033-41.

[4] Dufendach KA, Hornder JM, Bryan BC, Ackerman MJ. Congenital type I long QT syndrome unmasked by a highly caffeinated energy drink.  Heart Rhythm. 2012; 9: 285-8.

[5] Rottlaender D, Motloch LJ, Reda S, Larbig R, Hoppe UC. Cardiac arrest due to long QT syndrome associated with excessive consumption of energy drinks. Int J Cardiol 2011; Nov 4 [Epub].

[6] Rutledge M, Witthed A, Khouzam RN. It took a Redbull to unmask Brugada syndrome. Int J Cardiol 2012; Mar 31 [Epub].

[7] Gray B, Das J, Semsarian C. Consumption of energy drinks: a new provocation test for primary arrhythmogenic diseases. Int J Cardiol 2012; June 15 [Epub]


A year of sadness for Norway continues: the tragic sudden death of a world champion swimmer

Within the space of 6 weeks, a third elite athlete has had a cardiac arrest. Bolten footballer Fabrice Muamba survived a cardiac arrest during an FA cup match, while Livorno midfielder Permario Morisini died during an Italian second division match. From elite footballers, today we heard the tragic news of , a world champion swimmer who was one of Norway’s top medal hopes for the London Olympics, who died from cardiac arrest after collapsing in his bathroom during a training camp in Flagstaff, Arizona. He was 26. At this time, the cause of death remains unclear and results of the post-mortem are pending.

As I wrote in my recent blog, a very likely cause of Alexander’s death is an underlying genetic heart disorder, such as a hypertrophic cardiomyopathy or a primary arrhythmogenic disorder. The death again highlights the unpredictable nature of genetic heart diseases. People with these diseases can reach the highest levels of sporting excellence, in this instance, at the Olympic level, yet on a particular day, at a particular time, cardiac arrest occurs and death strikes. On this occasion, the death occurred not during sporting activity, but essentially during very light effort having a shower. Sudden death in the young can occur during exercise, but we have also seen in our clinics that many young deaths occur with minimal exercise or at rest. In some young people, death occurs during sleep. The reasons why sudden cardiac death in the young can occur at any time remain unclear.

After the tragic terrorist attack in Norway on July 22, 2011 that killed 69 innocent civilians, Alexander Dale Oen gave a grieving and hurting nation great hope and a reason to smile with his outstanding efforts in the swimming pool. He was marked as a possible gold medallist in the London Olympics. As with all sudden cardiac deaths in the young, Alexander Dale Oen’s death is a terrible tragedy. We await news of the cause of his death. Norway, and indeed the world, mourns.