PMID- 16177603
OWN - NLM
STAT- MEDLINE
DCOM- 20060206
LR  - 20190902
IS  - 0195-9131 (Print)
IS  - 0195-9131 (Linking)
VI  - 37
IP  - 9
DP  - 2005 Sep
TI  - Gender-specific usage of intramyocellular lipids and glycogen during exercise.
PG  - 1517-24
AB  - PURPOSE: Gender-specific differences in substrate utilization during exercise 
      have been reported, typically such that women rely more on fat than men. This 
      study investigated whether gender differences exist in the utilization of 
      intramyocellular lipids (IMCL) and glycogen. METHODS: IMCL and glycogen, as well 
      as total fat and carbohydrate (CHO) oxidation were measured in nine males and 
      nine females before, during, and after an endurance exercise. The trained 
      subjects exercised on a bicycle ergometer at 50% maximal workload for 3 h. IMCL 
      and glycogen were determined in the thigh by magnetic resonance spectroscopy. 
      Oxygen uptake (VO(2)) and carbon dioxide production were determined by open 
      circuit spirometry to calculate total fat and CHO oxidation. Relative power 
      output, percent of maximum heart rate, VO(2peak), and respiratory exchange ratio 
      were the same. RESULTS: Average fat oxidation was the same, whereas CHO oxidation 
      was significantly higher in males compared with females. The relative 
      contribution of these fuels to total energy used were similar in males and 
      females. Males and females depleted IMCL and glycogen significantly (P < 0.001) 
      during the 3-h exercise. IMCL levels at rest (P < 0.05) and its depletion during 
      exercise (P < 0.001) were significantly higher in males compared with females, 
      whereas glycogen was stored and used in the same range by both genders. 
      CONCLUSION: During this 3-h exercise, energy supplies from fat and CHO were 
      similar in both genders, and males as well as females reduced their IMCL stores 
      significantly. The larger contribution of IMCL during exercise in males compared 
      with females could either be a result of gender-specific substrate selection, or 
      different long-term training habit.
FAU - Zehnder, Monica
AU  - Zehnder M
AD  - Exercise Physiology, Institute for Human Movement Sciences, Swiss Federal 
      Institute of Technology Zurich and Institute of Physiology, University of Zurich.
FAU - Ith, Michael
AU  - Ith M
FAU - Kreis, Roland
AU  - Kreis R
FAU - Saris, Wim
AU  - Saris W
FAU - Boutellier, Urs
AU  - Boutellier U
FAU - Boesch, Chris
AU  - Boesch C
LA  - eng
PT  - Clinical Trial
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Med Sci Sports Exerc
JT  - Medicine and science in sports and exercise
JID - 8005433
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Dietary Fats)
RN  - 33X04XA5AT (Lactic Acid)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Adult
MH  - Blood Glucose/metabolism
MH  - Dietary Carbohydrates/metabolism
MH  - Dietary Fats/metabolism
MH  - Energy Metabolism/physiology
MH  - Exercise/*physiology
MH  - Female
MH  - Glycogen/*metabolism
MH  - Heart Rate/physiology
MH  - Humans
MH  - Lactic Acid/blood
MH  - Lipid Metabolism/*physiology
MH  - Male
MH  - Muscle Fibers, Skeletal/*metabolism
MH  - Nutrition Assessment
MH  - Oxidative Phosphorylation
MH  - Oxygen Consumption/physiology
MH  - Physical Endurance/*physiology
MH  - Sex Factors
MH  - Sports/physiology
EDAT- 2005/09/24 09:00
MHDA- 2006/02/07 09:00
CRDT- 2005/09/24 09:00
PHST- 2005/09/24 09:00 [pubmed]
PHST- 2006/02/07 09:00 [medline]
PHST- 2005/09/24 09:00 [entrez]
AID - 00005768-200509000-00010 [pii]
AID - 10.1249/01.mss.0000177478.14500.7c [doi]
PST - ppublish
SO  - Med Sci Sports Exerc. 2005 Sep;37(9):1517-24. doi: 
      10.1249/01.mss.0000177478.14500.7c.