PMID- 22436075
OWN - NLM
STAT- MEDLINE
DCOM- 20121105
LR  - 20160513
IS  - 1715-5312 (Print)
IS  - 1715-5312 (Linking)
VI  - 37
IP  - 2
DP  - 2012 Apr
TI  - Independent and combined effects of carbohydrate and caffeine ingestion on 
      aerobic cycling performance in the fed state.
PG  - 276-83
LID - 10.1139/h11-160 [doi]
AB  - The purpose of this study was to examine the independent and combined effects of 
      carbohydrate and caffeine ingestion on performance and various physiological 
      parameters during aerobic cycling ( approximately 1 h). Ten male cyclists (28 +/- 9 years, 73 +/- 6 
      kg, 66 +/- 9 mL.kg(-1).min(-1) maximal oxygen consumption) performed 20 min of 
      steady-state (SS) cycling (60% peak power (W(max))) followed by a simulated 20-km 
      time trial (TT) under placebo (PLA), carbohydrate (CHO), caffeine (CAF), and 
      combined CAF-CHO conditions, all of which were performed in the fed state. 
      CAF-CHO improved TT performance by 3.4% +/- 2% (84 +/- 57 s) compared with PLA (p < 
      0.05), whereas no differences were detected among CHO, CAF, and PLA. The SS 
      respiratory exchange ratio was elevated in CHO (0.92 +/- 0.03), CAF (0.96 +/- 0.07), 
      and CAF-CHO (0.95 +/- 0.02) compared with PLA (0.89 +/- 0.03) (p < 0.05). Post-SS and 
      post-TT blood glucose levels were also elevated in CAF-CHO (88.3 +/- 16.7 mg.dL(-1) 
      and 111.2 +/- 33.5 mg.dL(-1), respectively) compared with PLA (74.5 +/- 9.8 mg.dL(-1) 
      and 85.4 +/- 17.6 mg.dL(-1), respectively) (p < 0.05). Treatment conditions did not 
      differentially impact SS pulmonary ventilation, oxygen consumption, heart rate, 
      peak quadriceps muscle strength, rating of perceived exertion, or blood lactate. 
      CAF and CHO improved TT performance when taken together but not independently. 
      Although the present work did not yield any definitive physiological mechanisms 
      for the performance findings, these data suggest that cyclists in the fed state 
      should ingest carbohydrate and caffeine together to improve time trial 
      performance.
FAU - Acker-Hewitt, Tiffany L
AU  - Acker-Hewitt TL
AD  - Department of Kinesiology, James Madison University, Harrisonburg, VA 22807, USA.
FAU - Shafer, Brooke M
AU  - Shafer BM
FAU - Saunders, Michael J
AU  - Saunders MJ
FAU - Goh, Qingnian
AU  - Goh Q
FAU - Luden, Nicholas D
AU  - Luden ND
LA  - eng
PT  - Journal Article
PT  - Randomized Controlled Trial
DEP - 20120321
PL  - Canada
TA  - Appl Physiol Nutr Metab
JT  - Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition 
      et metabolisme
JID - 101264333
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 33X04XA5AT (Lactic Acid)
RN  - 3G6A5W338E (Caffeine)
SB  - IM
MH  - Adult
MH  - Blood Glucose/analysis
MH  - Caffeine/*administration & dosage
MH  - Diet
MH  - Dietary Carbohydrates/*administration & dosage
MH  - Double-Blind Method
MH  - Energy Intake/*drug effects
MH  - Energy Metabolism/drug effects
MH  - Exercise/*physiology
MH  - Exercise Test/methods
MH  - Heart Rate/drug effects
MH  - Humans
MH  - Lactic Acid/blood
MH  - Male
MH  - Muscle, Skeletal/drug effects/metabolism
MH  - Oxygen Consumption/drug effects
MH  - Young Adult
EDAT- 2012/03/23 06:00
MHDA- 2012/11/06 06:00
CRDT- 2012/03/23 06:00
PHST- 2012/03/23 06:00 [entrez]
PHST- 2012/03/23 06:00 [pubmed]
PHST- 2012/11/06 06:00 [medline]
AID - 10.1139/h11-160 [doi]
PST - ppublish
SO  - Appl Physiol Nutr Metab. 2012 Apr;37(2):276-83. doi: 10.1139/h11-160. Epub 2012 
      Mar 21.