Table 2.  Effect of caffeine or placebo on heart rate (HR), rating of perceived exertion (RPE), oxygen uptake (VO2) 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.