Placebo in sports nutrition: a proof-of-principle study involving caffeine supplementation

Autor(es):Mostrar menos -

Saunders, B. ^[1] ; de Oliveira, L. F. ^[1] ; da Silva, R. P. ^[1] ; de Salles Painelli, V. ^[1] ; Goncalves, L. S. ^[1] ; Yamaguchi, G. ^[1] ; Mutti, T. ^[1] ; Maciel, E. ^[2] ; Roschel, H. ^{[1, 2]} ; Artioli, G. G. ^{[1, 2]} ; Gualano, B. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Appl Physiol & Nutr Res Grp, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Sch Med, Rheumatol Div, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SCANDINAVIAN JOURNAL OF MEDICINE & SCIENCE IN SPORTS; v. 27, n. 11, p. 1240-1247, NOV 2017.
• Citações Web of Science: 35

Resumo

We investigated the effects of supplement identification on exercise performance with caffeine supplementation. Forty-two trained cyclists (age 37 +/- 8years, body mass {[}BM] 74.3 +/- 8.4kg, height 1.76 +/- 0.06m, maximum oxygen uptake 50.0 +/- 6.8mL/kg/min) performed a similar to 30min cycling time-trial 1h following either 6mg/kgBM caffeine (CAF) or placebo (PLA) supplementation and one control (CON) session without supplementation. Participants identified which supplement they believed they had ingested (caffeine, placebo, don't know) pre- and post-exercise. Subsequently, participants were allocated to subgroups for analysis according to their identifications. Overall and subgroup analyses were performed using mixed-model and magnitude-based inference analyses. Caffeine improved performance vs PLA and CON (P0.001). Correct pre- and post-exercise identification of caffeine in CAF improved exercise performance (+4.8 and +6.5%) vs CON, with slightly greater relative increases than the overall effect of caffeine (+4.1%). Performance was not different between PLA and CON within subgroups (all P>0.05), although there was a tendency toward improved performance when participants believed they had ingested caffeine post-exercise (P=0.06; 87% likely beneficial). Participants who correctly identified placebo in PLA showed possible harmful effects on performance compared to CON. Supplement identification appeared to influence exercise outcome and may be a source of bias in sports nutrition. (AU)

• Processo FAPESP: 14/11948-8 - Vida sem carnosina: desenvolvimento e caracterização de um modelo de rato nocaute para estudo do papel fisiológico da carnosina e suas implicações para o exercício físico e metabolismo muscular
• Beneficiário: Guilherme Giannini Artioli
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 11/19513-2 - Efeitos da Suplementação Crônica de Beta-Alanina Combinada ou não à Ingestão Aguda de Bicarbonato de Sódio sobre a Concentração Pico de Carnosina, o "Washout" de Carnosina e o Desempenho em Exercício Intenso.
• Beneficiário: Bryan Saunders
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/14746-4 - Metabolismo da carnosina no músculo esquelético: um estudo de múltiplas abordagens
• Beneficiário: Bruno Gualano
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/04806-0 - Efeitos de 12 semanas de treinamento intermitente de alta intensidade sobre as concentrações intramusculares de carnosina
• Beneficiário: Vitor de Salles Painelli
• Modalidade de apoio: Bolsas no Brasil - Doutorado