, which is a peer-reviewed, Open Access
Journal of the American Heart Association and the American Stroke Association,
Dallas, Texas, USA.
The lead author of
the study was Professor Sachin A. Shah, PharmD, FAHA, who is the Regional
Coordinator and Director of Pharmacy Research and Education at Travis Air Force
Base, Thomas J. Long School of Pharmacy and Health Sciences, University of the
Pacific, Stockton, California, USA.
The co-author of
the study was Professor Kate M. O'Dell, PharmD, BCPS, who is the Director of
Experiential Programs and Vice Chair of Pharmacy Practice at the Thomas J. Long
School of Pharmacy and Health Sciences, University of the Pacific, Stockton,
California, USA.
Composition of the
Energy Drinks
Two commercially
available caffeinated energy drinks or placebo was used in the study. Both these
energy drinks contained 304 and 320 milligrams (mg) of caffeine per 32 fluid
ounces (fl. oz). It is known that caffeine levels below 400 mg do not produce
any changes in electrocardiograms (ECG).
Besides caffeine,
other ingredients included taurine (amino acid containing sulfur),
glucuronolactone (a component of connective tissues and plant gums), and
vitamin B-Complex. The placebo drink was composed of cherry flavored carbonated
water and lime juice.
"Energy drinks are readily accessible and commonly
consumed by a large number of teens and young adults, including college
students. Understanding how these drinks affect the heart is extremely
important," says O'Dell.
Study Procedure
- Study
participants included 34 healthy volunteers aged 18-40 years
- Participants
were randomly assigned to drink one of the two caffeinated energy drinks
or the placebo drink
- 32 oz of
the drinks were consumed on three separate days
- Drinks
were consumed within 1 hour
- Rate of
consumption was no more than 16 oz in 30 minutes
- Electrical
activities of the participants' hearts were recorded by ECG
- The ECG
recorded the QT interval, which is a measure of the total duration of
ventricular activation (depolarization) and recovery (repolarization) during
the pumping action or beating of the heart
- Too short
or too long QT interval can cause abnormal heartbeats (arrhythmia),
which can be life-threatening
- Blood pressure was also measured and recorded
- All
measurements were taken at the beginning of the study and every 30 minutes
for up to 4 hours after finishing the drinks
Study Findings
- In energy drink consumers, the QT intervals for the
two drinks were six milliseconds or 7.7 milliseconds higher at 4 hours
compared to placebo drinkers
- In energy drink consumers, there was a 4-5 mmHg
increase in systolic and diastolic blood pressure, which was statistically
significant
- After consuming the energy drinks, the changes in
QT intervals were sustained over the 4-hour study period, rather than
short-lasting, which corroborates previous studies
"We found an association between consuming energy
drinks and changes in QT intervals and blood pressure that cannot be attributed
to caffeine. 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," says Shah.
Limitations of the
study
- The
effect of long-term or regular consumption of energy drinks was not
assessed
- The
effect of consumption of energy drinks in combination with alcohol, which
is very common, was not assessed
- The
results obtained were for healthy individuals in the age-group of 18-40
years, which could be different for other populations
Concluding Remarks
Professor Sachin
Shah concludes with a word of caution for energy drink consumers having
underlying heart conditions or
high blood pressure: "The public should be aware of the impact of energy
drinks on their body, especially if they have other underlying health
conditions," says Shah.
"Healthcare
professionals should advise certain patient populations, for example, people
with underlying congenital or acquired long QT syndrome or high blood pressure,
to limit or monitor their consumption."Funding Source
The study was
funded by the University of the Pacific, Stockton, California, USA.
Reference :- Energy drinks may increase risk of heart function abnormalities and blood pressure changes - (https://newsroom.heart.org/news/energy-drinks-may-increase-risk-of-heart-function-abnormalities-and-blood-pressure-changes?preview=2c57)
Source: Medindia