Scientists test what one can of an energy drink does to the human body

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1 Scientists test what one can of an energy drink does to the human body By Los Angeles Times, adapted by Newsela staff on Word Count 765 Dr. Steve Sun looks over a heart monitor display in the emergency room at St. Mary's Medical Center in San Francisco, California, Jan. 14, Photo: AP/Eric Risberg Downing an energy drink might seem like the perfect motivational aid before a trip to the gym. But a team of researchers has now tested the effects on the body of Rockstar brand drinks, and the results were not good for the heart. The team from the Mayo Clinic in Rochester, Minnesota, said that in just 30 minutes, one can of Rockstar boosted blood pressure and caused a big jump in levels of fight-or-flight type of hormone. The increase affects the cardiovascular system, which is made up of the heart and blood vessels. What's In That Can? Scientists worked with 25 volunteers, 14 men and 11 women. Each participant drank a 16- ounce can of Rockstar on an empty stomach in under five minutes. One drink contains 240 milligrams of caffeine, the ingredient in coffee and cola drinks that leads people to feel more awake. Rockstar also contains 2,000 milligrams of an amino acid called taurine, Guarana seed, ginseng root and milk thistle.

2 Taurine is an amino acid that helps regulate the level of water and minerals in the blood. Some studies say it improves mental and athletic performance. Guarana is made from the seeds of a South American tree and is high in caffeine. Ginseng root is believed to provide energy and lower blood sugar, and milk thistle has a few uses including also lowering cholesterol. Rockstar Vs. Placebo Another day, the same group of people drank a placebo energy drink that tasted just like Rockstar. However, it had none of the caffeine, taurine or other stimulants. The volunteers did not know which drink that they were given. All of the participants were healthy. They each were around 29 years old and had body mass indexes (BMIs) of about 25, on the border of normal weight and overweight. BMI is a measure of body fat based on weight and height. None of the volunteers were on medications, and none had consumed alcohol or caffeine in the day before each test. Before drinking, researchers measured participants' heart rates and blood pressure, and took blood samples. All of the tests were repeated 30 minutes later. Just like the volunteers, the researchers conducting the tests did not know who got the real Rockstar drink and who got the placebo. Blood Pressure Rising Before the drinks, all volunteers had normal heart rates and blood pressure readings. After drinking Rockstar, blood pressure readings increased. Blood pressure is measured in two readings. Systolic blood pressure measures the force created in arteries when the heart beats. Diastolic blood pressure measures the same thing, but between heartbeats. People with high blood pressure have a greater chance of developing heart disease. Systolic blood pressure in those who drank Rockstar rose an average of 6.2 percent, and diastolic blood pressure rose an average of 6.8 percent. The placebo drinkers were better off with systolic blood pressure rising just 3.1 percent. There was no change at all in diastolic blood pressure. Blood Pumping, Heart Pounding Both drinks caused participants' hearts to beat faster. Rockstar drinkers averaged 3 additional beats per minute. Those given the placebo averaged about 4 more beats per minute. Doctors said the difference between the two is unimportant. The biggest difference was in blood levels of norepinephrine, the hormone that can lead to the so-called fight-or-flight response. Norepinephrine narrows blood vessels and increases blood pressure and blood sugar levels. The hormone gets blood pumping and the heart

3 pounding. It mobilizes the brain and body for action, and is related to adrenaline. When it reaches much higher levels during situations of stress or danger, it leads to the fight-orflight response. That reaction causes humans or animals to prepare for fighting or fleeing. After consuming Rockstar, the average amount of norepinephrine rose 74 percent in the blood. There was only a 31 percent increase in the hormone for those who drank the placebo. Focus On Heart Health To see whether stressful situations would affect how the energy drink works, researchers asked the group to answer math questions, squeeze a hand grip or put a hand in ice water for two minutes. None of the activities made a difference. Stress may not make a difference, but scientists are still worried about the increases in blood pressure and norepinephrine. They recently published a study in the Journal of the American Medical Association, a magazine for scientists. The study found that the increases in blood pressure and hormone after consuming Rockstar could make people more likely to develop heart disease. They also said that results might be different with another energy drink or a larger group of volunteers.

4 Quiz 1 Scientists would most likely AGREE with which of the following statements? Rockstar is especially dangerous for people who are healthy. Consuming Rockstar is the best way to improve mental and athletic performance. Drinking Rockstar can be dangerous for people who already have cardiovascular issues. Because Rockstar is so dangerous to the cardiovascular system, people should consider consuming placebos instead. 2 Which of the following answer choices BEST describes the connection between consuming Rockstar and blood pressure? Consuming Rockstar increases the heart rate which raises blood pressure. Consuming Rockstar lowers the hear rate which lowers blood pressure. Consuming Rockstar increases the level of hormones in the blood with increases blood pressure. Consuming rockstar lowers the level of hormones in the blood with lowers blood pressure. 3 Read the last sentence of the article. They also said that results might be different with another energy drink or a larger group of volunteers. Why does the author conclude with this sentence? To suggest that the volunteers scientists used were not reliable. To suggest that there is more research to be done. To suggest that the research done by scientists in this experiment were not valuable. To suggest that other energy drinks probably would not have the same effects on the heart that Rockstar did.

5 4 Read the second paragraph of the section "Blood Pumping, Heart Pounding." How does this paragraph contribute to the article? It defines norepinephrine. It explains the effect of norepinephrine on the body. It connect the term adrenaline to its clinical term, norepinephrine. It grounds the results of the experiment in its effects on the heart.

6 Answer Key 1 Scientists would most likely AGREE with which of the following statements? Rockstar is especially dangerous for people who are healthy. Consuming Rockstar is the best way to improve mental and athletic performance. Drinking Rockstar can be dangerous for people who already have cardiovascular issues. Because Rockstar is so dangerous to the cardiovascular system, people should consider consuming placebos instead. 2 Which of the following answer choices BEST describes the connection between consuming Rockstar and blood pressure? Consuming Rockstar increases the heart rate which raises blood pressure. Consuming Rockstar lowers the hear rate which lowers blood pressure. Consuming Rockstar increases the level of hormones in the blood with increases blood pressure. Consuming rockstar lowers the level of hormones in the blood with lowers blood pressure. 3 Read the last sentence of the article. They also said that results might be different with another energy drink or a larger group of volunteers. Why does the author conclude with this sentence? To suggest that the volunteers scientists used were not reliable. To suggest that there is more research to be done. To suggest that the research done by scientists in this experiment were not valuable. To suggest that other energy drinks probably would not have the same effects on the heart that Rockstar did.

7 4 Read the second paragraph of the section "Blood Pumping, Heart Pounding." How does this paragraph contribute to the article? It defines norepinephrine. It explains the effect of norepinephrine on the body. It connect the term adrenaline to its clinical term, norepinephrine. It grounds the results of the experiment in its effects on the heart.