Abstract
Background:
Perhaps the most ubiquitous example of energy shots is the product known as 5-Hour ENERGY. With caffeine being the primary ingredient, it has been hypothesized that the claimed effects of this product are due in most part to the caffeine content, estimated to be ∼200 mg.
Objective:
The aim of this study was to compare the effects of 5-Hour ENERGY to caffeine only, as well as to a placebo, on subjective feelings of energy and mood, objective measures of cognitive performance, heart rate, and blood pressure in men and women.
Methods:
Ten healthy men (Mage=22.7±1.1 years) and 10 healthy women (Mage=22.1±0.4 years) ingested either 5-Hour ENERGY, caffeine only (200 mg), or a placebo on three different days, separated by ∼1 week using a randomized design. Before and at 1, 3, and 5 h following ingestion of the assigned condition, subjects completed a subjective assessment of energy and mood, as well as tests of cognitive performance (Trail Making Test, Digit Symbol Substitution Test). Heart rate and blood pressure were measured.
Results:
Neither caffeine nor 5-Hour ENERGY resulted in an improvement in subjective feelings or in objective cognitive performance. Heart rate was not impacted by treatment, but blood pressure (diastolic in particular) was elevated (∼4–10 mmHg) with caffeine and 5-Hour ENERGY.
Conclusion:
These data indicate that in a controlled laboratory environment, subjective feelings and cognitive performance are not impacted by caffeine or 5-Hour ENERGY. Heart rate is unaffected by treatment, and blood pressure increases in a minor and similar manner with both 5-Hour ENERGY and caffeine.
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