PMID- 31046515
OWN - NLM
STAT- MEDLINE
DCOM- 20200914
LR  - 20200914
IS  - 1522-1601 (Electronic)
IS  - 0161-7567 (Linking)
VI  - 126
IP  - 6
DP  - 2019 Jun 1
TI  - Graded reductions in preexercise muscle glycogen impair exercise capacity but do 
      not augment skeletal muscle cell signaling: implications for CHO periodization.
PG  - 1587-1597
LID - 10.1152/japplphysiol.00913.2018 [doi]
AB  - We examined the effects of graded muscle glycogen on exercise capacity and 
      modulation of skeletal muscle signaling pathways associated with the regulation 
      of mitochondrial biogenesis. In a repeated-measures design, eight men completed a 
      sleep-low, train-low model comprising an evening glycogen-depleting cycling 
      protocol followed by an exhaustive exercise capacity test [8 x 3 min at 80% peak 
      power output (PPO), followed by 1-min efforts at 80% PPO until exhaustion] the 
      subsequent morning. After glycogen-depleting exercise, subjects ingested a total 
      of 0 g/kg (L-CHO), 3.6 g/kg (M-CHO), or 7.6 g/kg (H-CHO) of carbohydrate (CHO) 
      during a 6-h period before sleeping, such that exercise was commenced the next 
      morning with graded (P < 0.05) muscle glycogen concentrations (means +/- SD: L-CHO: 
      88 +/- 43, M-CHO: 185 +/- 62, H-CHO: 278 +/- 47 mmol/kg dry wt). Despite differences (P 
      < 0.05) in exercise capacity at 80% PPO between trials (L-CHO: 18 +/- 7, M-CHO: 
      36 +/- 3, H-CHO: 44 +/- 9 min), exercise induced comparable AMPK(Thr172) 
      phosphorylation (~4-fold) and PGC-1alpha mRNA expression (~5-fold) after exercise and 
      3 h after exercise, respectively. In contrast, neither exercise nor CHO 
      availability affected the phosphorylation of p38MAPK(Thr180/Tyr182) or 
      CaMKII(Thr268) or mRNA expression of p53, Tfam, CPT-1, CD36, or PDK4. Data 
      demonstrate that when exercise is commenced with muscle glycogen < 300 mmol/kg 
      dry wt, further graded reductions of 100 mmol/kg dry weight impair exercise 
      capacity but do not augment skeletal muscle cell signaling. NEW & NOTEWORTHY We 
      provide novel data demonstrating that when exercise is commenced with muscle 
      glycogen below 300 mmol/kg dry wt (as achieved with the sleep-low, train-low 
      model) further graded reductions in preexercise muscle glycogen of 100 mmol/kg 
      dry wt reduce exercise capacity at 80% peak power output by 20-50% but do not 
      augment skeletal muscle cell signaling.
FAU - Hearris, Mark A
AU  - Hearris MA
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
FAU - Hammond, Kelly M
AU  - Hammond KM
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
FAU - Seaborne, Robert A
AU  - Seaborne RA
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
FAU - Stocks, Ben
AU  - Stocks B
AD  - Medial Research Council-Arthritis Research UK Centre for Musculoskeletal Aging 
      Research, School of Sport, Exercise and Rehabilitation Sciences, University of 
      Birmingham , Birmingham , United Kingdom.
FAU - Shepherd, Sam O
AU  - Shepherd SO
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
FAU - Philp, Andrew
AU  - Philp A
AUID- ORCID: 0000-0003-3860-4136
AD  - Medial Research Council-Arthritis Research UK Centre for Musculoskeletal Aging 
      Research, School of Sport, Exercise and Rehabilitation Sciences, University of 
      Birmingham , Birmingham , United Kingdom.
AD  - Diabetes and Metabolism Division, Garvan Institute of Medical Research , Sydney, 
      New South Wales , Australia.
FAU - Sharples, Adam P
AU  - Sharples AP
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
AD  - Institute for Science and Technology in Medicine, Keele University, Guy Hilton 
      Research Centre , Stoke-on-Trent , United Kingdom.
FAU - Morton, James P
AU  - Morton JP
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
FAU - Louis, Julien B
AU  - Louis JB
AUID- ORCID: 0000-0002-9109-0958
AD  - Research Institute for Sport and Exercise Sciences, Liverpool John Moores 
      University , Liverpool , United Kingdom.
LA  - eng
PT  - Journal Article
DEP - 20190502
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Dietary Carbohydrates)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Adult
MH  - Dietary Carbohydrates/metabolism
MH  - Exercise/*physiology
MH  - Exercise Test/methods
MH  - Exercise Tolerance/*physiology
MH  - Glycogen/*metabolism
MH  - Humans
MH  - Male
MH  - Muscle, Skeletal/*metabolism
MH  - Organelle Biogenesis
MH  - Phosphorylation/physiology
MH  - Physical Endurance/*physiology
MH  - Signal Transduction/*physiology
MH  - Young Adult
OTO - NOTNLM
OT  - exercise capacity
OT  - mitochondrial biogenesis
OT  - muscle glycogen
OT  - train low, sleep low
EDAT- 2019/05/03 06:00
MHDA- 2020/09/15 06:00
CRDT- 2019/05/04 06:00
PHST- 2019/05/03 06:00 [pubmed]
PHST- 2020/09/15 06:00 [medline]
PHST- 2019/05/04 06:00 [entrez]
AID - 10.1152/japplphysiol.00913.2018 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2019 Jun 1;126(6):1587-1597. doi: 
      10.1152/japplphysiol.00913.2018. Epub 2019 May 2.