Previous studies have shown that caffeine – a stimulant found in coffee, soda and energy drinks – increases blood pressure and decreases heart rate in children, adults and adolescents. In a new study published in the online Pediatrics, researchers found that caffeine affects boys and girls differently after puberty.
The study, led by Jennifer Temple, PhD, an associate professor at the University at Buffalo School of Public Health and Health Professions, examined 96 children and adolescents ranging in age from 8 to 17, noting their heart rate and blood pressure before and after they consumed a caffeinated beverage or a placebo over the course of six visits.
“All of the children in the study showed a decrease in heart rate and an increase in blood pressure after consuming caffeine,” Temple told LiveScience. “After puberty, however, caffeine was found to affect boys and girls differently, with boys having a greater response to caffeine than girls.”
Specifically, the findings showed that caffeine lowered the heart rates of kids past puberty by about 3 to 8 beats per minute. Boys past puberty experienced a slightly greater increase in blood pressure than girls. In addition, Temple and her team found girls had varied responses to caffeine during their menstrual cycles.
“The data on the girls’ menstrual cycles does suggest that the cardiovascular response to caffeine changes along with hormonal fluctuations during menstruation,” said Temple. However, she noted that more research was needed to determine if reactions to caffeine were related to physiological factors or patterns of caffeine consumption.
Despite the recommendation of the American Academy of pediatrics that caffeine should not be a part of children’s diet, the growing popularity of caffeinated soda and energy drinks has led to an increased use by children and adolescents of these beverages. According to a recent report, 73 percent of U.S. children consume caffeine each day.
“Parents should monitor how much soda, coffee or energy beverages their teenagers drink and help them understand the risk associated with taking in large amounts of caffeine,” John P. Higgins, MD, a sports cardiologist with the University of Texas Health Science Center at Houston, told Health Day.
Higgins, who was not associated with the study, recommended that young children avoid caffeine entirely and that teens shouldn’t have more than 100 milligrams of caffeine a day, which is roughly the amount in a typical cup of coffee. He also cautioned that teens with medical issues such as heart or sleep problems should probably avoid caffeine altogether or “discuss possible safe limits with their physician.”