PMID- 26850449 OWN - NLM STAT- MEDLINE DCOM- 20161213 LR - 20220318 IS - 1439-6327 (Electronic) IS - 1439-6319 (Linking) VI - 116 IP - 4 DP - 2016 Apr TI - Carbohydrate dependence during prolonged simulated cycling time trials. PG - 781-90 LID - 10.1007/s00421-016-3333-y [doi] AB - PURPOSE: We determined the effect of suppressing lipolysis via administration of Nicotinic acid (NA) and pre-exercise feeding on rates of whole-body substrate utilisation and cycling time trial (TT) performance. METHODS: In a randomised, single-blind, crossover design, eight trained male cyclists/triathletes completed two series of TTs in which they performed a predetermined amount of work calculated to last ~60, 90 and 120 min. TTs were undertaken after a standardised breakfast (2 g kg(-1) BM of carbohydrate (CHO)) and ingestion of capsules containing either NA or placebo (PL). RESULTS: Plasma [free fatty acids] were suppressed with NA, but increased in the later stages of TT90 and TT120 with PL (p < 0.05). There was no treatment effect on time to complete TT60 (60.4 +/- 4.1 vs. 59.3 +/- 3.4 min) or TT90 (90.4 +/- 9.1 vs. 89.5 +/- 6.6 min) for NA and PL, respectively. However, TT120 was slower with NA (123.1 +/- 5.7 vs. 120.1 +/- 8.7 min, p < 0.001), which coincided with a decline in plasma [glucose] during the later stages of this ride (p < 0.05). For TTs of the same duration, the rates of whole-body CHO oxidation were unaffected by NA, but decreased with increasing TT time (p < 0.05). CHO was the predominant substrate for all TTs contributing between 83 and 94 % to total energy expenditure, although there was a small use of lipid-based fuels for all rides. CONCLUSION: (1) NA impaired cycling TT performance lasting 120 min, (2) cycling TTs lasting from 60 to 120 min are CHO dependent, and (3) there is an obligatory use of lipid-based fuels in TTs lasting 1-2 h. FAU - Torrens, Samuel L AU - Torrens SL AD - Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, VIC, 3065, Australia. FAU - Areta, Jose L AU - Areta JL AD - Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway. FAU - Parr, Evelyn B AU - Parr EB AD - Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, VIC, 3065, Australia. FAU - Hawley, John A AU - Hawley JA AD - Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, VIC, 3065, Australia. john.hawley@acu.edu.au. AD - Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. john.hawley@acu.edu.au. LA - eng PT - Clinical Trial PT - Journal Article PT - Randomized Controlled Trial DEP - 20160205 PL - Germany TA - Eur J Appl Physiol JT - European journal of applied physiology JID - 100954790 RN - 0 (Dietary Carbohydrates) RN - 12001-76-2 (Vitamin B Complex) RN - 2679MF687A (Niacin) SB - IM MH - Adolescent MH - Adult MH - *Athletic Performance MH - Bicycling MH - Cross-Over Studies MH - Dietary Carbohydrates/administration & dosage/adverse effects/*pharmacology MH - *Exercise MH - Humans MH - Lipolysis/drug effects MH - Male MH - Niacin/administration & dosage/adverse effects/*pharmacology MH - Single-Blind Method MH - Vitamin B Complex/administration & dosage/adverse effects/*pharmacology OTO - NOTNLM OT - Fat OT - High-intensity cycling OT - Nicotinic acid OT - Performance OT - Substrate utilisation EDAT- 2016/02/07 06:00 MHDA- 2016/12/15 06:00 CRDT- 2016/02/07 06:00 PHST- 2015/08/05 00:00 [received] PHST- 2016/01/20 00:00 [accepted] PHST- 2016/02/07 06:00 [entrez] PHST- 2016/02/07 06:00 [pubmed] PHST- 2016/12/15 06:00 [medline] AID - 10.1007/s00421-016-3333-y [pii] AID - 10.1007/s00421-016-3333-y [doi] PST - ppublish SO - Eur J Appl Physiol. 2016 Apr;116(4):781-90. doi: 10.1007/s00421-016-3333-y. Epub 2016 Feb 5.