TY - JOUR
T1 - The effect of double blind carbohydrate ingestion during 60 km of self-paced exercise in warm ambient conditions
AU - Nassif, Camila
AU - Gomes, Aline Regina
AU - Peixoto, Gustavao H.C.
AU - Chagas, Mauro Heleno
AU - Soares, Danusa Dias
AU - Silami-Garcia, Emerson
AU - Drinkwater, Eric
AU - Cannon, Jack
AU - Marino, Francesco
N1 - Includes bibliographical references.
PY - 2014
Y1 - 2014
N2 - This study evaluated double blind ingestions of placebo (PLA) versus 6% carbohydrate (CHO) either as capsules (c) or beverage (b) during 60 km self-paced cycling in the heat (32uC and 50% relative humidity). Ten well-trained males (mean 6 SD: 2663 years; 64.567.7 kg and 70.768.8 ml.kg21.min21 maximal oxygen consumption) completed four separate 60 km time trials (TT) punctuated by 1 km sprints (14, 29, 44, 59 km) whilst ingesting either PLAb or PLAc or CHOb or CHOc. The TT was not different among treatments (PLAb 130.2611.2 min, CHOb 140.5618.1 min, PLAc 143.1629.2 min, CHOc 137.3620.1 min; P.0.05). Effect size (Cohen’s d) for time was only moderate when comparing CHOb – PLAb (d = 0.68) and PLAb – PLAc (d = 0.57) whereas all other ES were ‘trivial’ to ‘small’. Mean speed throughout the trial was significantly higher for PLAb only (P,0.05). Power output was only different (P,0.05) between the sprints and low intensity efforts within and across conditions. Core and mean skin temperatures were similar among trials. We conclude that CHO ingestion is of little or no benefit as a beverage compared with placebo during 60 km TT in the heat.
AB - This study evaluated double blind ingestions of placebo (PLA) versus 6% carbohydrate (CHO) either as capsules (c) or beverage (b) during 60 km self-paced cycling in the heat (32uC and 50% relative humidity). Ten well-trained males (mean 6 SD: 2663 years; 64.567.7 kg and 70.768.8 ml.kg21.min21 maximal oxygen consumption) completed four separate 60 km time trials (TT) punctuated by 1 km sprints (14, 29, 44, 59 km) whilst ingesting either PLAb or PLAc or CHOb or CHOc. The TT was not different among treatments (PLAb 130.2611.2 min, CHOb 140.5618.1 min, PLAc 143.1629.2 min, CHOc 137.3620.1 min; P.0.05). Effect size (Cohen’s d) for time was only moderate when comparing CHOb – PLAb (d = 0.68) and PLAb – PLAc (d = 0.57) whereas all other ES were ‘trivial’ to ‘small’. Mean speed throughout the trial was significantly higher for PLAb only (P,0.05). Power output was only different (P,0.05) between the sprints and low intensity efforts within and across conditions. Core and mean skin temperatures were similar among trials. We conclude that CHO ingestion is of little or no benefit as a beverage compared with placebo during 60 km TT in the heat.
U2 - 10.1371/journal.pone.0104710
DO - 10.1371/journal.pone.0104710
M3 - Article
C2 - 25110952
SN - 1932-6203
VL - 9
SP - 1
EP - 8
JO - PLoS One
JF - PLoS One
IS - 8
M1 - e104710
ER -