7-Day Caffeine and Upper-Body Power in Active Women

This study investigated the effects of a 7-day caffeine supplementation on heart rate variability, cognitive performance, and upper-body anaerobic power in active women. Thirty healthy active women aged 25-30 years participated in this double-blind, placebo-controlled trial. Participants were randomly assigned to receive either 5 mg/kg of caffeine or a placebo daily for 7 days. Heart rate variability, cognitive function (measured by the Stroop test), and upper-body anaerobic power (measured by a 20-second Wingate test) were assessed at baseline, 90 minutes after supplementation, and 30 minutes after exercise. The primary outcome was peak anaerobic power. The study aimed to determine whether short-term caffeine habituation enhances exercise performance without altering cardiac autonomic function or cognitive performance.