PMID- 38223937
OWN - NLM
STAT- MEDLINE
DCOM- 20240228
LR  - 20240228
IS  - 1522-1490 (Electronic)
IS  - 0363-6119 (Linking)
VI  - 326
IP  - 3
DP  - 2024 Mar 1
TI  - Effects of carbohydrate availability on cycling endurance at the maximal lactate 
      steady state.
PG  - R266-R275
LID - 10.1152/ajpregu.00178.2023 [doi]
AB  - The impacts of carbohydrate (CHO) availability on time to task failure (TTF) and 
      physiological responses to exercise at the maximal lactate steady state (MLSS) 
      have not been studied. Ten participants (3 females, 7 males) completed this 
      double-blinded, placebo-controlled study that involved a ramp incremental test, 
      MLSS determination, and four TTF trials at MLSS, all performed on a cycle 
      ergometer. With the use of a combination of nutritional (CHO, 7 g/kg, and 
      placebo, PLA, 0 g/kg drinks) and exercise interventions [no exercise (REST) and 
      glycogen-reducing exercise (EX)], the four conditions were expected to differ in 
      preexercise CHO availability (REST(CHO) > REST(PLA) > EX(CHO) > EX(PLA)). TTF at 
      MLSS was not improved by CHO loading, as REST(CHO) (57.1 [16.6] min) and 
      REST(PLA) (57.1 [15.6] min) were not different (P = 1.00); however, TTF was  approximately 50% 
      shorter in EX conditions compared with REST conditions on average (P < 0.05), 
      with EX(CHO) (39.1 [9.2] min)  approximately 90% longer than EX(PLA) (20.6 [6.9] min; P < 
      0.001). There were effects of condition for all perceptual and cardiometabolic 
      variables when compared at isotime (P < 0.05) and task failure (TF; P < 0.05), 
      except for ventilation, perceptual responses, and neuromuscular function 
      measures, which were not different at TF (P > 0.05). Blood lactate concentration 
      was stable in all conditions for participants who completed 30 min of exercise. 
      These findings indicate that TTF at MLSS is not enhanced by preexercise CHO 
      supplementation, but recent intense exercise decreases TTF at MLSS even with CHO 
      supplementation. Extreme fluctuations in diet and strenuous exercise that reduce 
      CHO availability should be avoided before MLSS determination.NEW & NOTEWORTHY 
      Carbohydrate (CHO) loading did not increase participants' ability to cycle at 
      their maximal lactate steady state (MLSS); however, performing a glycogen 
      depletion task the evening before cycling at MLSS reduced the time to task 
      failure, even when paired with a high dose of CHO. These diet and exercise 
      interventions influenced blood lactate concentration ([BLa]) but not the 
      stability of [BLa]. Activities that reduce CHO availability should be avoided 
      before MLSS determination.
FAU - Quinn, Colton P
AU  - Quinn CP
AD  - Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, 
      Canada. ROR: https://ror.org/03yjb2x39
FAU - McDougall, Rachel M
AU  - McDougall RM
AD  - Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, 
      Canada. ROR: https://ror.org/03yjb2x39
FAU - Aboodarda, Saied Jalal
AU  - Aboodarda SJ
AUID- ORCID: 0000-0001-5108-2235
AD  - Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, 
      Canada. ROR: https://ror.org/03yjb2x39
FAU - Murias, Juan M
AU  - Murias JM
AUID- ORCID: 0000-0002-6460-6453
AD  - Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, 
      Canada. ROR: https://ror.org/03yjb2x39
AD  - College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
FAU - MacInnis, Martin J
AU  - MacInnis MJ
AUID- ORCID: 0000-0002-0377-5800
AD  - Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, 
      Canada. ROR: https://ror.org/03yjb2x39
LA  - eng
GR  - RGPIN-2018-06424/Gouvernement du Canada | Natural Sciences and Engineering 
      Research Council of Canada (NSERC)/
GR  - Faculty of Kinesiology/University of Calgary (U of C)/
PT  - Journal Article
PT  - Randomized Controlled Trial
DEP - 20240115
PL  - United States
TA  - Am J Physiol Regul Integr Comp Physiol
JT  - American journal of physiology. Regulatory, integrative and comparative 
      physiology
JID - 100901230
RN  - 33X04XA5AT (Lactic Acid)
RN  - 9005-79-2 (Glycogen)
RN  - 0 (Polyesters)
SB  - IM
MH  - Male
MH  - Female
MH  - Humans
MH  - *Lactic Acid
MH  - *Physical Endurance/physiology
MH  - Oxygen Consumption
MH  - Exercise Test
MH  - Glycogen
MH  - Polyesters
OTO - NOTNLM
OT  - blood lactate concentration
OT  - critical intensity
OT  - exercise metabolism
OT  - performance fatiguability
OT  - sports nutrition
EDAT- 2024/01/15 06:43
MHDA- 2024/02/28 06:43
CRDT- 2024/01/15 04:57
PHST- 2024/02/28 06:43 [medline]
PHST- 2024/01/15 06:43 [pubmed]
PHST- 2024/01/15 04:57 [entrez]
AID - 10.1152/ajpregu.00178.2023 [doi]
PST - ppublish
SO  - Am J Physiol Regul Integr Comp Physiol. 2024 Mar 1;326(3):R266-R275. doi: 
      10.1152/ajpregu.00178.2023. Epub 2024 Jan 15.