Table 3.
Incidence of side effects reported immediately after and the morning after ingestion of a caffeinated gel or a placebo.
| Placebo | Caffeine | Placebo | Caffeine | |
|---|---|---|---|---|
| Immediately After Testing Session | Immediately After Testing Session | Morning After Testing Session | Morning After Testing Session | |
| Muscle soreness | 0 | 0 | 0 | 0 |
| Increased urine production | 0 | 6 | 0 | 6 |
| Tachycardia and heart palpitations | 6 | 12 | 0 | 0 |
| Increased anxiety | 0 | 18 | 0 | 0 |
| Headache | 0 | 0 | 0 | 0 |
| Abdominal/gut discomfort | 0 | 6 | 0 | 0 |
| Insomnia | n/a | n/a | 0 | 6 |
| Increased vigor/activeness | 12 | 41 | 0 | 0 |
| Perception of improved performance | 6 | 35 | n/a | n/a |
Data are frequencies for 17 participants, expressed as the percentage of positive cases; none of the comparisons were significant based on the McNemar test.