Caffeine is the world's most widely consumed psychoactive substance and, when used strategically, one of the most effective performance-enhancing compounds available. The research is unambiguous: caffeine improves strength output, endurance performance, reaction time, and perceived effort across virtually all athletic contexts.
Effective dose: 3-6mg per kilogram of body weight. For an 80kg person, that's 240-480mg. A standard cup of coffee contains 80-120mg of caffeine, meaning 2-3 cups in the hour before training provides an effective dose for most people. Caffeine supplements (tablets or powder) provide more precise dosing at lower cost. Timing: consume 30-60 minutes before training for peak blood levels. Effects last 4-6 hours, which is relevant for evening training sessions that may affect sleep.
Tolerance develops with regular caffeine use, reducing its performance-enhancing effects. Strategies to maintain efficacy: cycling off caffeine for 1-2 weeks every 2-3 months, reserving high-dose caffeine for important training sessions (competitions, PRs, hard training sessions), and using lower habitual doses (1-2 cups of coffee daily) to preserve sensitivity. Side effects at high doses include anxiety, elevated heart rate, GI distress, and sleep disruption. For morning training, standard coffee consumption is sufficient. For evening training, consider caffeine-free pre-workouts or accepting slightly reduced performance rather than compromising sleep quality - sleep deprivation has far larger negative performance effects than caffeine has positive ones.