The high toll of energy drinks: Insomnia, palpitations and elevated anxiety

In the supermarket, a row of colorful cans announcing exotic flavors welcomes shoppers to the energy drinks aisle. These peach, mango, coconut and watermelon beverages feature a massive dose of sugar, along with generous portions of caffeine, taurine and ginseng, stimulants all. They promise to wake up their consumer, improve their concentration, combat fatigue and increase alertness. More often than not, they succeed in these duties: while a cup of coffee has about 100 milligrams of caffeine, a half-liter can of this kind of soft drink can reach up to 160 milligrams. But staying alert comes with a price tag, and the medical community warns that abuse of energy elixirs can take their toll on one’s health.

Consumption of energy drinks is becoming more and more popular — particularly among adolescents — and scientists have gone public with their unease when it comes to the potential impacts on the cardiovascular system and mental health of intense or sustained consumption of these beverages. Studies have found evidence of increased insomnia, heart palpitations, anxiety and gastrointestinal conditions associated with drinking energy beverages. And, according to the amount of the stimulants one drinks and one’s predisposition, they can take an even greater toll: there have been reports of occasional cases of cardiac arrest and even death linked to the abuse of these beverages.

According to a study published this year, around 32% of people around the world consumed an energy drink during the last month. Experts consulted for this article are especially worried about young people and the effects these beverages can have on a body that is still developing. “It’s a curious social phenomenon. We should be worried, although not alarmed, because this is not a very harmful substance. But there are sub-groups of the population who are more at risk and who can experience more problems with long-term mental health because their body is still developing,” sums up Chema González Echevarri, a neurologist at the Unit for Neurocognitive Conditions at the Joan XXIII Hospital in Tarragona, Spain. According to the ESTUDES study conducted by Spain’s Ministry of Health among students 14 to 18 years old, in 2023, nearly half (47.7%) had drunk an energy drink within the last 30 days.

There aren’t too many trips to the emergency room that can be chalked up to these drinks, says Lidia Martínez, an emergency pediatrician at the Sant Joan de Déu Children’s Hospital in Barcelona, but that doesn’t mean the phenomenon isn’t worth keeping an eye on. “It is worrying, because a product is being marketed to adolescents that creates addiction — caffeine does create addiction — and the population is not aware of that risk,” says the specialist, who is also one of the coordinators of the Spanish Society of Pediatric Emergency Medicine’s intoxications working group. Energy drink cans carry warnings that their consumption is not recommended for children and pregnant women.

We’re living in an era of burnout, and energy drinks are packaged as “fuel” for our exhausted bodies, capable of increasing physical endurance and imparting a feeling of well-being. But Spain’s Ministry of Health points out in a report that “they have significant cerebral and metabolic consequences.” “Some of the adverse effects of energy drinks are stimulation of the central nervous and cardiovascular systems and their relationship with being overweight and obesity. Regular consumption of energy drinks has been associated with caffeine overdose, hypertension, loss of bone mass and osteoporosis. Among secondary effects stemming from regular consumption are palpitations, insomnia, nausea, vomiting and frequent urination,” the study’s authors state.

A scientific review of the effects of acute and chronic consumption of these drinks identified 86 cases of people who suffered from adverse effects stemming from such beverages. They were primarily related to cardiac damage such as arrhythmia, but there were also nine cases of cardiac arrest (three of which resulted in death). There was also documentation of neurological effects on the central nervous system (convulsions and cerebral vasculopathy) and gastrointestinal problems, such as hepatitis and pancreatitis.

Sugar and caffeine in the spotlight

Doctors are particularly concerned about two central ingredients of energy drinks: sugar and caffeine (or any other stimulants they may include.) González Echevarri, who is also a member of the Spanish Society of Neurology, describes the latter’s impact on the brain: “Stimulants like taurine and caffeine modulate a neurotransmitter that increases concentration, but they can also cause problems with insomnia or reduce one’s ability to cope with anxiety, with all the effects that can imply, from tachycardia to tremors and irritability.”

One study suggests that caffeine, in addition to causing dependence, is associated with gastrointestinal and psychological problems; ginseng has also been linked to elevated risks of developing some tumors and ginkgo biloba, another ingredient often used in energy drinks, has been associated with higher risk of spontaneous bleeding, including intracranial hemorrhage. González Echevarri characterizes the probability of stroke or cerebral hemorrhage among teens as “extremely rare,” saying, “The young body can withstand a lot because it has higher capacity for repair and everything is in good shape.”

Even so, among people with certain susceptibility to cardiovascular and mental health problems or anxiety, consumption of energy drinks can exacerbate some symptoms, adds González Echevarri. “There is a higher risk of these stimulants detonating something that was already there. People who are anxious, depressive or suffer from insomnia are very sensitive to stimulants and these drinks can worsen their symptoms. At the cardiovascular level, it is common to experience tachycardia and sometimes, arrhythmia — but normally when that happens, it is because the person is more susceptible to such conditions or else they are consuming large amounts of the beverages.”

Acute intoxication does not have many repercussions. But sustained consumption goes unnoticed and has clear effects on physical and emotional health

Lidia Martínez, emergency room pediatrician at Sant Joan de Déu children’s hospital in Barcelona

Miguel Caínzos,a cardiologist at Barcelona’s Hospital del Mar, emphasizes that “more studies are needed because there is little information on caffeine and taurine’s effects on the cardiovascular system,” though he does say that they can cause “palpitations and feelings of tachycardia.” Along the same lines, Luis Rodríguez Padial, president of the Spanish Society of Cardiology, warns that, although some patients who seek out consultations with cardiologists are “on time”, there is “a certain amount of concern” regarding the phenomenon. He says that “if there is an overdose of caffeine, it can lead to arrhythmia.”

When it comes to sugar, Caínzos is blunt. “There is concern regarding frequent, maintained consumption of these beverages due to their high sugar content, because that can generate resistance to insulin, obesity and diabetes,” all conditions that can lead to other cardiovascular diseases. “Chronic consumption of this kind of quantity of sugar is worrisome,” he says. Many brands now sell low-sugar options.

Dangerous when mixed with alcohol

The consumption of energy drinks doesn’t often land patients in the emergency room, but there is one serious situation in which they are sometimes implicated: alcohol poisoning, says Martínez. “It’s a problem because these sodas compensate for the effects of alcohol and since there is not as much awareness of the effect [of the intoxicant] on the body, more risks can be taken and, when the stimulant effect wears off, the depression generated by the alcohol increases,” explains Martínez, who is also the head of the pediatric toxicology office at Sant Joan de Déu.

Energy drinks can disguise the depressive effects of alcohol, which can lead to people drinking more. According to the ESTUDES study, nearly one in every five students between the ages of 14 and 18 has mixed energy drinks with alcohol during the last 30 days.

Martínez recommends that we not minimize the impact these drinks can have on our health, although doctors rarely ask about one’s caffeine consumption, even when a patient comes in with symptoms of anxiety. “If we asked adolescents about their caffeine consumption, we’d likely be surprised, and could discover a connection to headaches or symptoms of anxiety,” she surmises.

The pediatrician is embarking on a multi-faceted study to look at the caffeine consumption of kids who wind up in the emergency room. She recommends incorporating such questions into differential diagnosis. “Acute intoxication does not have many repercussions. But sustained consumption goes unnoticed and has clear effects on physical and emotional health,” she says. She insists that an energy drink is not like a traditional cola: “The amount of caffeine is very different [half a liter of cola can contain 56 milligrams] and, in addition to caffeine, energy drinks have other substances that are psychostimulants and cardio-stimulants. An adolescent’s brain needs to be free of toxins to develop as best it can.”

Experts warn that, though there is evidence regarding short-term consequences of energy drink consumption, long-term effects of chronic consumption are largely unknown. González Echevarri warns that, “in a brain that is still developing, anything that modulates neurotransmission can cause changes.” Caínzos emphasizes the need to provide more information “on the risks of drinking a few cans.” “You can’t trivialize the amount consumed in a short period of time,” he says.

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