Table 2. Mean blood lactate for subjective placebo responders (n = 3) and percentage difference from mean blood lactate for placebo non-responders (n = 9) in informed caffeine/received caffeine and informed caffeine/received placebo conditions. Condition Lactate mmol·l Difference (%) from placebo non-responders Chances effect is clinically beneficial (trivial/harmful)+ Mean (SD) Mean (SD) 95% CI* Informed caffeine/received caffeine 7.4 (0.8) 19.3 (49.0) -26.6 to 65.2 17 (4/80) Informed caffeine/received placebo 7.2 (1.1) 16.7 (49.1) -27.1 to 60.4 19 (4/77) 95% CI = 95% confidence interval. smallest worthwhile effect of 1.5%.