Table 2 Effect of caffeine or placebo on heart rate (HR), rating of perceived exertion (RPE), oxygen uptake (VO) and respiratory exchange ratio (RER) during 15 min of steady state cycling (Phase A). Values are means (±SD, n=10).
Time Placebo Caffeine Mean change (%) ± 90%
confidence limits
P
HR 5 min 130 (12) 129 (10) -.07 (.57)
10 min 134 (10) 136 (13) -.37 (.68)
15 min 138 (12) 140 (12 .23 (.61) .81
RPE 5 min 11 (2) 10 (2) -.04 (.56)
10 min 11 (2) 11 (2) -
15 min 11 (2) 11 (2) - .74
VO2 (mL·kg-1·min-1) 5 min 16.05 (3.92) 16.93 (4.03) .22 (.24)
10 min 16.79 (3.91) 17.27 (3.33) .12 (.19)
15 min 15.85 (3.64) 17.78 (3.93) .53 (.28) .08
RER 5 min .95 (.08) .94 (.08) -.21 (.52)
10 min .89 (.05) .91 (.07) .43 (1.18)
15 min .90 (.04) .88 (.08) -.35 (.73) .31
P indicates interaction effect of time and trial.