We have seen many studies that show how caffeine may enhance cognitive and physical performance. Some supplements provide the greatest improvement when used consistently over long periods of time. However, caffeine has the greatest effect when used sporadically, when a boost is needed. Learning when and how to take caffeine can make it a valuable tool for your mental and physical work.
Caffeine May Enhance Performance at Low Points
This study had 15 active males, aged 19-21, complete cognitive and physical tasks with a placebo or 6 mg caffeine per kg body weight, at six different times of day. Reaction time, attention, and a 5-meter multiple shuttles run test were measured.
Caffeine improved performance scores at each time of day. For cognitive performance, the worst scores were at 7:00 and 13:00 and the best scores were at 11:00 and 17:00. Caffeine improved the worst scores 6-6.4% while only improving the best scores 3.4-3.8%. For physical performance, the worst scores were at 7:00 and the best scores were at 17:00. Caffeine improved the worst scores 1.6% while only improving the best scores 0.5%.
Caffeine supplementation improved performance at all points in the day. But it made a more significant difference during times of lowest performance.
Caffeine May Work for Everyone Sometimes
Similar to how a study with more participants is more reliable, a study with more repetitions also tends to be more reliable. This study tested the myth that some people are non-responders to caffeine. On eight different occasions, while supplementing with a placebo or 3 mg caffeine per kg bodyweight, a group of 11 participants completed an incremental cycling test to volitional fatigue and an adapted version of the Wingate cycling test.
All of the 11 participants experienced improved performance with caffeine supplementation on at least three occasions, in either the graded exercise test or the Wingate test. None of the participants were completely immune to the effects of caffeine.
The researchers noted that the participants with the lowest ergogenic effects were the ones with the greatest cardiovascular side effects. It is not yet pinned down if the different responses are linked to genes (CYP1A2 and ADORA2A) or environmental factors like tolerance.
Habitual Caffeine May Reduce Power Benefits
Many studies have confirmed that caffeine can increase power output. Usually caffeine studies use subjects who do not usually take large amounts of caffeine. And the subjects usually consume 3-6 mg caffeine per kg bodyweight for the study.
In contrast, this study involved 15 strength-trained male athletes, 20-32 years old, who regularly consumed 4-6.4 mg caffeine per kg bodyweight (324-528 mg caffeine). To measure power output and bar velocity, participants completed a bench press exercise of three sets of five repetitions at 50% one-rep max. The exercise was completed 4 times with a week between trials. The exercise was performed 60 minutes after taking a placebo or 3, 6, or 9 mg caffeine per kg bodyweight.
The researchers found no significant differences between the power output or the bar velocity among the 4 trials. Researchers observed some performance benefit in the 9 mg per kg group compared to placebo. But at 9 mg caffeine per kg body weight, 87% of participants expressed side effects such as heart palpitations, anxiety, headache, and insomnia.
The researchers concluded that habitual caffeine intake limits physiological responses to acute caffeine doses.
This group of studies shows that caffeine may improve performance in everyone at least part of the time, and the greatest benefit may come at times when it's most needed. However, performance enhancement varies by person. And habitual use of caffeine may decrease the benefits of a single dose.
Habitual use of caffeine results in the need for a larger dose of caffeine in order to provide a performance benefit. And with that larger dose comes greater risk of side effects.
Multiple repeated comparisons of trials, using both a placebo and an active supplement, improve reliability of results. But I imagine that it can get tedious for participants and costly for researchers.
Judging from studies such as these, I suggest that you try to pay attention to how a supplement affects your body. And avoid using caffeine supplements daily. Save caffeine for the times when you need greater cognitive or physical performance.
Thrivous developed Surge Acute Nootropic for occasional use to enhance energy, both cognitive and physical, without sacrificing focus. Surge provides 100 mg Caffeine in each capsule. And Surge also provides clinical doses of L Theanine and Panax Ginseng to expand the performance enhancement benefits of Caffeine.