Caffeine is known to increase performance when taken before endurance activities, but more than 80% of studies have focused on men. A recent randomized, double-blind, crossover study out of Queensland, Australia, aimed to determine whether or not gender affects ergogenic responses to caffeine.
Researchers conducted the study with 27 adult endurance-trained male and female cyclists and triathletes, all of whom took either a placebo or a caffeine capsule (3 milligrams per kilogram of body mass) 90 minutes before a performance time trial. Every subject completed an exercise test to exhaustion, two familiarization trials and two performance trials.
Data analysis showed that caffeine, when compared with a placebo, improved performance by approximately 4% in both men and women. In spite of this, subjects reported no difference in rating of perceived exertion between the two protocols. Following the exercise, women experienced much higher plasma caffeine concentrations than men, with similar gains.
Study authors concluded that current recommendations for caffeine intake (3-6 mg/kg/BM) before exercise—with a goal of enhancing endurance performance—is equally applicable to men and women. The study is available in Medicine & Science in Sports & Exercise (2019; 51 , 1195–1202).