Author(s): GONZÁLEZ-MOHÍNO, F., VALERO, F., LARA, B., GALLO-SALAZAR, C., ARECES, F., SALINERO, J.J., Institution: UNIVERSITY OF CASTILLA-LA MANCHA, Country: SPAIN, Abstract-ID: 450

INTRODUCTION:
According to previous research, believing ingested caffeine can improve sports performance to a similar extent to receiving caffeine (1, 2), so, the use of placebos can be an alternative to the use of caffeine. The perceived ergogenicity of caffeine (3, 4) could lead to these positive effects. However, the expectancy induced by caffeine can propitiate suffering the typical caffeine side effects too. Previous research found that caffeine ingestion increased diverse side effects, such as insomnia, activeness, and nervousness (3, 4). This study aimed to analyse the prevalence of perceived side effects after the ingestion of a placebo informed as caffeine.
METHODS:
Thirty-five individuals (28 men, 7 women; 28±11 years, 71±8 kg, 176±7 cm) volunteered to participate. Participants were provided with informed consent forms before participating in the investigation in which they were informed of the experimental procedures and risks. The study was approved by the local Research Ethics Committee and was performed under the latest version of the Declaration of Helsinki. On the day of testing, participants ingested a placebo informed as caffeine and completed a specific sports session. The morning after, participants were provided with a side-effects survey to determine if they had perceived any caffeine-associated side effects the hours after ingestion. This survey included questions about participants’ activeness, nervousness, gastrointestinal problems, irritability, diuresis, headache, and insomnia using a yes/no scale. This methodology has been previously used to assess the prevalence of side effects after the intake of caffeine in the sports context (4).

RESULTS:
The ingestion of a placebo informed as caffeine resulted in almost 4 out of 10 participants (37.1%) perceiving greater activeness. In addition, 17.1% reported nervousness, 14.3% increased diuresis, 11.4% headache, 5.7% gastrointestinal discomfort, and 5.7% insomnia. No one reported being irritable.
CONCLUSION:
The placebo effect can improve sports performance, but the use of a placebo reported as caffeine can produce adverse side effects in some individuals. Coaches/nutritionists employing placebos may wish to consider other options (i.e. other fictive substances) with known ergogenic effects but without adverse side effects.