(HealthDay News) — Gender differences in the effects of caffeine emerge after puberty, and responses vary across the menstrual cycle for postpubertal girls, according to a study published online June 16 in Pediatrics.

Jennifer L. Temple, PhD, from the University at Buffalo in New York, and colleagues examined gender differences in the cardiovascular response to caffeine after puberty, as well as differences in response across the menstrual cycle. Heart rate and blood pressure were examined before and after administration of two doses of caffeine (1 and 2mg/kg) and placebo in 52 prepubertal (8–9-year-olds) and 49 postpubertal (15–17-year-olds) children. Participants included 54 boys and 47 girls.

The researchers identified an interaction between gender and caffeine dose, with a greater response to caffeine seen for boys than girls. Interactions were identified for pubertal phase, gender, and caffeine dose, with gender differences observed in postpubertal participants, but not in prepubertal participants. In postpubertal girls, differences in responses to caffeine were identified across the menstrual cycle, with greater decreases in heart rate in the midfollicular phase and greater increases in blood pressure in the midluteal phase.

“These data suggest that gender differences in response to caffeine emerge after puberty,” the authors write. “Future research will determine the extent to which these gender differences are mediated by physiological factors, such as steroid hormones, or psychosocial factors, such as more autonomy and control over beverage purchases.”

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