A previously healthy 28-year-old man wound up in the emergency room
with heart problems after drinking two energy drinks a day, as well as
alcohol, for months, according to a new report.
The man experienced a very fast heart rate and an irregular heart
rhythm (called arrhythmia), and the report supports a connection found
in many previous studies: that there is a link between energy-drink consumption and heart problems.
Although the new report cannot prove that the energy drinks caused the
man's abnormal heart rate, this case, combined with other previous
reports, shows the abnormal heart rhythm "could be a complication" of
energy-drink consumption, the researchers, from the University of
Florida, reported in the July/August issue of the Journal of Addiction
Given the popularity of energy drinks, doctors should consider asking
patients about their energy-drink consumption if they have an
unexplained heart rhythm problem, the researchers said.
Previous studies have found that consuming just one energy drink can increase blood pressure, sometimes to unhealthy levels. And there have been several reports of young people who have suffered heart attacks after consuming energy drinks, including a 2015 report of a 26-year-old who drank eight to 10 of these highly caffeinated beverages a day.
In the new report, the researchers wrote that the man went to the
hospital after he started vomiting blood. He told the doctors that he
had consumed two Monster energy drinks that day, each of which contained
160 milligrams of caffeine, for a total of 320 mg of caffeine that day.
(For comparison, an 8-ounce cup of coffee contains about 95 to 200 mg
of caffeine, according to the Mayo Clinic.) He also reported having
consumed two to three beers that day.
A physical exam showed normal results, except that the man's heart rate was very fast — 130 beats per minute. (A normal heart rate
is usually between 60 and 100 beats per minute.) A test of his heart's
electrical activity showed he had atrial fibrillation, or an abnormal
heart rhythm. The problem is not usually life-threatening, but it can
increase the risk of stroke and other heart complications, according to
the Mayo Clinic.
The man was treated with two heart medications (diltiazem and
metoprolol), and his heart rate returned to normal within 24 hours. He
was released from the hospital three days later, and as of one year
after the incident, he had not experienced any more problems with his
heart rhythm, the report said.
Monster energy drinks contain about four to five times the amount of caffeine per serving as caffeinated soft drinks. Caffeine
can cause heart cells to release calcium, which may affect heartbeat,
and high amounts of caffeine can cause heart palpitations and vomiting,
the researchers said.
Between 2004 and 2012, the Food and Drug Administration received 40
reports of people experiencing health problems after drinking Monster
energy drinks, including abnormal heart rate, increased blood pressure,
loss of consciousness and cardiac arrest, the report said.
Still, up to 400 mg of caffeine per day is considered safe for healthy adults, according to the Mayo Clinic.
It's possible that other ingredients in energy drinks, along with
caffeine, contribute to the development of heart problems, the
researchers said. For example, taurine, a common ingredient in energy
drinks, may heighten the effects of caffeine, the researchers said.
Another ingredient, called guarana, also usually contains caffeine and
may boost the caffeine content of the whole beverage above what's listed
on the label, they said.
Further studies of the ingredients in energy drinks are needed for
experts to better understand how the beverages may be linked with heart
problems, the researchers noted.
Consuming alcohol along with energy drinks
might also increase the effects of caffeine, allowing the compound to
stay in the blood longer, the researchers said. Caffeine also could
lower the sedative effects of alcohol, allowing people to continue
drinking longer and consume more alcohol, which, in turn, could increase
intoxication and lead to arrhythmias, they said.
Although the long-term effects of energy-drink consumption are not
known, "it may be reasonable to limit their use, especially in
combination with alcohol or illicit substances and in patients
predisposed to arrhythmias," the researchers concluded.
At the time of publication, Monster Energy had not responded to an email request from Live Science for comment on the study.
Original article on Live Science.
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