Fig. 8From: The physiological and perceptual effects of plant extracts (Catha Edulis Forsk) during sustained exerciseThis shows the mean (and SEM) of rate of perceived exertion of all volunteers after consuming khat and after taking the placebo. Red symbols show data from the placebo day and the black symbols show data from the khat day. There are increases in the both means of perceived exertion during the khat and placebo trialsBack to article page