The last sip of fluid you swallow at the one-hour cutoff should be used to wash down your prerace caffeine pills, if you choose to use them. Caffeine levels in the bloodstream peak one hour after caffeine consumption, so if you take your NoDoz or Stay Awake tablets one hour before your race begins you will be feeling the full effects just as you start to run. Caffeine pills are preferable to coffee for several reasons. First of all, it is simply not practical to have coffee available one hour before the start of a marathon or half marathon, when you’re likely to be already at the race site. Even if it were practical to have coffee available at the start line, drinking enough coffee to get the maximum performance benefit just one hour before you started running would almost certainly cause you to require a bathroom break in the middle of the race. Furthermore, research suggests that, for whatever reason, pure caffeine is more effective than coffee as a performance booster. Finally, it’s much easier to control your caffeine dosage with pills than it is with coffee.
The optimal dosage of caffeine before exercise has been much researched. A minimum dose of 2 mg of caffeine per kilogram of body weight is required for an ergogenic effect. Doses above 6 mg per kilogram of body weight carry no additional benefit. A 2012 study out of Australia’s Griffith University found that a caffeine dose of 3 mg per kilogram of body weight enhanced cycling performance as much as twice that amount. Based on the principle that it’s wise not to use more of any drug than is needed to serve its purpose, I suggest that you aim to consume approximately 3 mg of caffeine per kilogram you weigh before your races unless you are normally a heavy caffeine user, in which case a dosage closer to the maximum effective dosage of 6 mg per kilogram may be more effective. Caffeine pills generally come in 200 mg tablets, so you may need to divide tablets to get the right amount. But it’s okay to be approximate. A 150-pound (68.2 kg) runner would need to consume 205 mg of caffeine to hit the mark of 3 mg per kilogram. In that case, a single 200 mg would be close enough. Note that if you plan to consume caffeinated energy gels during the race (a topic I’ll revisit in the next chapter), you should take somewhat less than the maximum effective dosage before the race so that the total amount of caffeine you take before and during the race does not exceed 6 mg per kilogram of body weight.