Table 3.

Heart rate during exercise at 50 and 80%V˙o 2max 1, 3, and 6 h after caffeine or placebo ingestion

Time1 h3 h6 h
CaffeinePlaceboCaffeinePlaceboCaffeinePlacebo
Nonusers3-150 (n = 8)
 5 min 50%V˙o 2max 125 ± 8122 ± 8125 ± 12124 ± 7128 ± 12124 ± 10
 5 min3-153 80%V˙o 2max 164 ± 73-151 162 ± 9168 ± 113-151 164 ± 8167 ± 103-151 162 ± 8
 10 min3-153 80%V˙o 2max 170 ± 83-151 168 ± 9174 ± 113-151 171 ± 10174 ± 113-151 170 ± 9
 15 min3-15380%max174 ± 83-151 172 ± 10177 ± 103-151 174 ± 10178 ± 113-151 175 ± 10
 Exhaustion3-153 80%V˙o 2max 180 ± 83-151 174 ± 14183 ± 113-151 177 ± 11182 ± 123-151 177 ± 12
Users (n = 13)
 5 min 50%V˙o 2max 110 ± 9116 ± 9113 ± 11110 ± 10113 ± 11115 ± 14
 5 min3-153 80%V˙o 2max 154 ± 93-151 155 ± 9154 ± 123-151 152 ± 11155 ± 113-151 152 ± 10
 10 min3-153 80%V˙o 2max 164 ± 103-151 163 ± 7164 ± 113-151 161 ± 11162 ± 113-151 159 ± 10
 15 min3-153 80%V˙o 2max 169 ± 103-151 167 ± 8168 ± 93-151 165 ± 10166 ± 123-151 164 ± 10
 Exhaustion3-153 80%V˙o 2max 173 ± 103-151 170 ± 7171 ± 103-151 168 ± 10170 ± 123-151 166 ± 10
  • Values are means ± SD (in beats/min).

  • F3-150 Nonuser at 50% and at 80% V˙o 2max > user.

  • F3-151 Caffeine at 80% V˙o 2max > placebo at 80% V˙o 2max.

  • F3-153 Heart rate increased with time.