Within four hours of energy drink consumption, maximum systolic blood pressure (the top number that represents pressure while the heart contracts to pump blood to the body) increased by 7.9 percent on day one and 9.6 percent on day seven; diastolic blood pressure (the bottom number that represents the pressure when the heart relaxes between beats) increased by 7 percent and 7.8 percent, respectively, within two hours of energy drink consumption. Heart rate increased by 7.8 percent on day one and 11 percent on day seven.
Over the duration of the study, heart rates increased five to seven beats per minute and systolic blood pressure increased 10 millimeters of mercury (mmHg) after energy drink consumption, the researchers reported. No significant ECG changes were observed.
This occurred while participants were sitting in chairs watching movies, said Kalus. The increases in heart rate and blood pressure werent enough for something to happen acutely, but a person on hypertension medication or who has cardiovascular disease may not respond as well.
While energy drinks increase concentration and wakefulness, people with risk factors for heart disease could have a bad reaction. The subjects in this study were healthy with low blood pressure.
Kalus feels that the increases in blood pressure and heart rate may be due to the caffeine and taurine in the drinks. However, the energy drink used in the study had as much caffeine as one to two cups of coffee, and usually the effect of this amount of caffeine on blood pressure would be expected to wane over 2 or 3 days of regular intake. Some of the other energy drinks contain much higher levels of caffeine, he said.
Thousands of young adults are using these drinks, Kalus said. Some are mixing the energy drinks with alcohol. We dont necessarily know how much they are drinking at a time or whether they are drinking be
|Contact: Karen Astle|
American Heart Association