The detrimental side effects of energy drinks

Analysis by Dr. Joseph Mercola Fact Checked

energy drink

Story at-a-glance -

  • Although not marketed as an energy drink, the original formulation of Coke contained two stimulants — caffeine and cocaine; currently, common energy drinks are a combination of over 300 mg of caffeine with other metabolic agents proven to boost energy, disrupt sleep, alter heart function and interfere with arterial function
  • Experts are concerned the combination of caffeine with other ingredients in energy drinks, found in much higher concentrations than natural food or plants, may enhance the effects of caffeine and trigger negative health effects, including emergency room treatment or death
  • The antioxidants in straight black organic coffee has health benefits, statistically lowers risk of all-cause mortality and may improve cognitive function
  • Hydrating with molecular hydrogen helps boost energy without added risk; also pay attention to other lifestyle choices, such as getting quality sleep, staying well-hydrated, supporting your gut microbiome and eating a well-balanced diet, high in healthy fats and low in net carbohydrates

Over the past centuries, people have used a variety of beverages to give them an extra burst of energy. While trends have changed from tea to coffee, to soft drinks and then energy drinks, the ultimate goal has been the same. Although not marketed as such, the first energy drink may have been Coca-Cola, launched in 1886, as it originally contained two strong stimulants — caffeine and cocaine.1

The company's name — Coca-Cola — was derived from the coca plant from which cocaine is derived and the kola nut, the source of caffeine. In 1960, Taisho Pharmaceuticals in Japan made the first drink specifically targeted at increasing energy. It contained essential vitamins, taurine and niacin, metabolic agents proven to boost energy and concentration.2

Building on this, in 1987 Austrian Dietrich Mateschitz added caffeine and sugar and renamed the drink Red Bull.3 By 1997, Red Bull was introduced in the U.S., followed closely by Monster Energy drink and then 5-Hour Energy. An explosion of sales occurred by 2006 and while others have garnered part of the market, Red Bull remains the best known with annual sales near $2 billion globally.

By 2012, 13 deaths had been reported over the past four years as the result of using 5-Hour Energy.4 The market value is predicted to reach $61 billion by 20215 and it's estimated 30% of teenagers from 12 to 17 years drink energy drinks on a regular basis.6

In a study of military personnel, researchers discovered nearly 45% of deployed members drink at least one energy drink per day and 13.9% drink more than three daily.7 While manufacturers promote them as supplements to boost physical and cognitive performance, there have also been detrimental side effects reported, particularly cardiovascular and neurological.

The number of annual emergency department visits involving energy drink more than doubled between 2007 and 2011.8 Recent research9 shows energy drinks significantly prolong electrocardiogram measurements and raise blood pressure.

Study finds energy drinks interfere with heart function

The goal of the research was to determine the impact energy drinks may have on electrocardiographic and hemodynamic parameters in healthy volunteers with no known heart disease risk. They gathered 34 participants with an average age of 22 years and enrolled them in a randomized, double-masked, placebo-controlled crossover study.10

The participants drank 32 ounces of energy drink A, energy drink B or a placebo over 60 minutes on three study days. Between each study day, they underwent a six-day washout period.

Researchers also measured brachial and central blood pressures at baseline, and every 30 minutes for four hours. None of the participants were on medications except three who were taking oral contraceptives.

The primary end measurement was the assessment of various heart rhythms and electrical properties of the heart, referred to in medical terms as the QT and QTc (corrected QT) intervals, PR interval and QRS duration.

The QT interval refers to your heart rhythm, starting at ventricular depolarization (known as QRS complex) to ventricular repolarization (known as the T wave).11 In layman’s terms, it can be explained as the electrical pulses that govern the pumping action of your heart.

Long or prolonged QT refers to fast, chaotic heartbeats that can trigger fainting, seizure or even sudden death.12 According to the Food and Drug Administration, prolongation of the QTc interval (which is measured by the ECG machine) is an established risk factor for heart arrhythmias.13

Results confirm the energy drinks caused a prolongation of the QTc interval that remained sustained over a four-hour period, as opposed to being a transient effect. Both commonly available energy drinks had a similar effect on the electrocardiogram parameters.

They contained a combination of caffeine, taurine, glucuronolactone and B vitamins. The placebo drink contained lime juice, carbonated water and cherry flavoring.14 

The energy drinks also raised brachial and central blood pressure measurements. They recommended those with acquired or congenital long QT syndrome15 and/or those with high blood pressure should limit their intake of energy drinks as the beverages may worsen these conditions.

Both experimental energy drinks contained less than 350 milligrams of caffeine. Doses under 400 mg are not expected to influence electrocardiographic measurements.16 One of the limitations of the study was it measured only short-term effects and not the effect of routine consumption of energy drinks.

Lead author Sachin Shah, Pharm. D., professor of pharmacy practice at the University of the Pacific’s Thomas J. Long School of Pharmacy in Stockton, California, stated the effects went beyond what they might expect from caffeine alone. He warned:17

"We urgently need to investigate the particular ingredient or combination of ingredients in different types of energy drinks that might explain the findings seen in our clinical trial.”

Energy drink may reduce diameter of your arteries

Dr. John Higgins, chief of cardiology at Lyndon B. Johnson Hospital, led a study looking at the effects of energy drinks on blood vessel function. He enlisted 44 nonsmoking, healthy medical students in their 20s and tested the students’ blood vessels before and 90 minutes after they drank a 24-ounce energy drink.18

The researchers found noticeably diminished function and diameter of blood vessels using an ultrasound measurement indicating overall blood vessel health. They found dilation was 5.1% in diameter before and fell to 2.8% after, suggesting an acute impairment of function.19

Higgins reports a lot of young people use energy drinks when they exercise, or in circumstances when the body requires top functioning arterial blood flow, so oxygen may get to the cells quickly. However, this reduction in vessel diameter effectively restricts blood flow and oxygen delivery. He commented:20

“It's more work for the heart and less oxygen supply for the heart. This could explain why there have been cases where kids have had a cardiac arrest after an energy drink.”

Another study21 published in the Journal of the American Medical Association proposed energy drinks would increase blood pressure and heart rate in a healthy adult at rest and these changes would be associated with sympathetic activation.

While a small study sample size was used, researchers found the energy drink significantly increased blood pressure and catecholamines in young healthy adults. They proposed these acute changes may predispose an individual to an increased risk of a cardiovascular event. Higgins advises avoiding energy drinks when you are exercising or studying.22

High caffeine levels may interact with other ingredients

As mentioned, the energy drinks tested in the featured study had caffeine levels at least 50 mg below what would be expected to trigger heart changes. The American Beverage Association, however, continues to stand behind the safety of energy drinks, as the ingredients in them are also found in other foods and have been studied for safety.

Most energy drinks contain caffeine, added sugars and B-vitamins. They may also contain legal stimulants such as guarana; taurine, an amino acid naturally found in meat and fish; and L-carnitine, a substance the body uses to turn fat into energy. However, as Katherine Zeratsky, clinical dietitian at the Mayo Clinic told CNN:23

"Overall, the concern is that these vitamins, amino acids and herbals are often in higher concentrations than naturally in food or plants, and the effects when combined especially with caffeine may be enhanced."

In other words, Zeratsky identifies one of the same challenges existing in tests of any chemical added in manufacturing. In most cases, chemicals are tested in isolation and researchers are unable to predict what may happen when they're combined. Higgins also told CNN more research was needed to determine how ingredients might interact and trigger negative health effects.24

"They're sort of a black box. We really don't know a lot about them. People need to be aware of that. For certain groups, it could be potentially dangerous, like for those under 18, women who are pregnant, people who have a caffeine sensitivity, people who don't consume caffeine on a regular basis and people who are taking certain medications, like Adderall for attention deficit (disorder)."

Depending on the amount of caffeine ingested, researchers have found doses above 200 mg may be linked to caffeine intoxication.25 Symptoms may include gastrointestinal upset, muscle twitching, anxiety, restlessness and insomnia. High caffeine intake has also been associated with chronic daily headaches.

By comparison, the American Academy of Pediatrics26 recommends children not exceed 100 mg of caffeine a day as it is associated with elevated pressure blood pressure in adolescence. In 2007, the CDC reports, 1,145 adolescents from 12 to 17 years old were admitted to the emergency room with energy drink-related health emergencies. By 2011 the number had climbed to 1,499.27

Energy drinks interfere with quality sleep

Among the other groups who warned against the use of energy drinks, the U.S. military advises troops against drinking too many as it interferes with sleep and leads to long periods of fatigue. In a study28 conducted in 2010, researchers found service members who drank three or more drinks a day reported four hours of sleep or less on average per night.

Another study29 found an association between energy drink consumption and sleep problems with alcohol use in adolescents. They examined the potential interactions with the concurrent prediction of alcohol use and found those who drank energy drinks and experienced insomnia, or daytime fatigue, were at higher risk for alcohol use.

Quality of sleep is fundamental to supporting your immunity, learning and metabolism. Although energy drinks are popular among college students, they also interfere with sleep quality and may have long-term detrimental effects.

In one study,30 researchers evaluated the effect of energy drinks on students enrolled at Copperbelt University School of Medicine in Zambia; 157 students were enrolled and the majority of participants reported having poor sleep quality with a statistically significant association between poor sleep and energy drink consumption.

Benefits of coffee without the added chemicals

Although the mix of caffeine and additives may potentiate the effects of caffeine, and most energy drinks have high levels of caffeine, it is important not to discount the health advantages of plain organic coffee. For instance, in one study,31 researchers found those who drank the most coffee over a 16.4-year follow-up period had a statistically significant lower risk of all-cause mortality.

For all participants, drinking coffee was associated with a reduction of death from digestive diseases. Past studies have also demonstrated coffee drinking may be protective against four of the most prevalent killer diseases: heart disease, cancer, diabetes and stroke.

Researchers hypothesize the powerful antioxidants in coffee called polyphenols may provide your cells with adequate defense against reactive oxygen species or free radicals. Drinking coffee was also linked to a lower risk of glioma brain tumors and may help your brain function, lowering your risk of Alzheimer's disease and other forms of dementia.32

However, it's important to drink the right kind of coffee as light and medium roast have an increase amount of acrylamide, a toxic byproduct found in 40% of calories consumed by the average American.33

Acrylamide has been found to cause cancer in animals and likely will cause cancer in humans as well. For the best flavor and optimal health benefits, choose organic, shade-grown whole bean coffee that you grind yourself. This helps prevent rancidity, as pre-ground coffee may be rancid by the time you drink it.

The lighter the roast the more acrylamide is left in the coffee bean. Although darker roast coffee may have a bitter flavor, the longer it is roasted the more acrylamide is burned off the bean.34

Hydrate with molecular hydrogen for boost without risk

Another option to boost your energy levels is molecular hydrogen. This refers to diatomic hydrogen, or H2 gas where two hydrogen atoms are combined. Molecular hydrogen has been found to remediate oxidative stress, one of the most fundamental mechanisms destroying human health.35

Molecular hydrogen has been shown to benefit nearly every organ in the human body and it targets and mitigates the root causes of many diseases, inflammation and oxidation. Ingesting hydrogen-rich water has demonstrated clinical benefits, safety and effectiveness.

The added benefits to health and wellness, as well as an increase in energy level, maybe enough for you to consider using molecular hydrogen water to rehydrate after exercise. The addition of hydrogen to water has these benefits in animal and human studies:

A natural antioxidant to combat stress; research36 has shown it destroys free radicals without breaking down into new ones

Improve quality of life after radiation treatment, reducing biological reactions without compromising anti-tumor effects37

May reinforce quality of life by increasing nervous system function38

The scavenger effect of hydrogen-rich water may reduce oxidative stress in those with rheumatoid arthritis39

May regulate immune responses and cardiometabolic disease40

Demonstrates significant and rapid improvement in those with psoriasis after bathing the affected area in hydrogen-rich water related to the effective reactive oxygen species scavenger ability41

Demonstrated anti-fatigue effects on swimming mice42

Pre-exercise hydration with hydrogen-rich water reduced lactate levels and improved exercise-induced decline of muscle function43

Accelerated wound healing of radiation-induced skin lesions44

More strategies to boost your energy levels

It is important to consider how all your lifestyle choices impact your energy level and your ability to maintain focus and attention. In other words, while a jolt of caffeine midday may be useful occasionally, it is likely not something you want to depend on as a daily strategy. Instead, it's important to evaluate your lifestyle choices as they relate to your overall health and energy.

Quality sleep, supporting a strong gut microbiome, eating a well-balanced diet and staying hydrated are just some of the strategies you'll find will make a difference in your daily energy levels. For more information about these strategies, and help to incorporate them in your everyday life, see these previous articles:

+ Sources and References