PMID- 16253627
OWN - NLM
STAT- MEDLINE
DCOM- 20051228
LR  - 20131121
IS  - 0026-0495 (Print)
IS  - 0026-0495 (Linking)
VI  - 54
IP  - 11
DP  - 2005 Nov
TI  - Substrate oxidation during exercise at moderate and hard intensity in middle-aged 
      and young athletes vs sedentary men.
PG  - 1411-9
AB  - This study investigated the combined effects of endurance training and aging on 
      substrate oxidation during exercise. Thirty-one healthy male subjects in 4 groups 
      (8 middle-aged trained cyclists, 8 young trained cyclists, 7 middle-aged 
      sedentary men, and 8 young sedentary men) performed 2 50-minute cycle ergometer 
      exercise tests, below and above (+/-15%) their individual ventilatory threshold 
      (VT). Substrate oxidation was evaluated by indirect calorimetry during the 
      steady-state tests. Aging decreased carbohydrate (CHO) use (P<.05) in all 
      subjects regardless of fitness status or exercise intensity. However, it declined 
      2-fold less in the trained men (P<.05) and was associated with a stronger 
      epinephrine response (P<.05). During hard-intensity exercise, endurance training 
      increased by 100% CHO use in the older men (P<.05). In the younger men, training 
      increased fat oxidation but did not change CHO oxidation, resulting in a marked 
      decrease in the ratio between CHO and fat used at high-intensity exercise (-93%; 
      P<.05). These data suggest an age-related decline in the use of CHO as an energy 
      source in exercising men, independent of intensity level. This decline, however, 
      is attenuated in well-trained men for exercise intensities above the VT. In view 
      of these findings, we hypothesize that cycling training performed at a specific 
      exercise intensity (ie, 15% above VT) may improve CHO mobilization and use in 
      middle-aged men.
FAU - Manetta, Jerome
AU  - Manetta J
AD  - Metabolic Unit, Service Central de Physiologie Clinique, Centre d'Exploration et 
      de Readaptation des Anomalies Metaboliques et Musculaires (CERAMM), 34295 
      Montpellier Cedex 5, France.
FAU - Brun, Jean-Frederic
AU  - Brun JF
FAU - Prefaut, Christian
AU  - Prefaut C
FAU - Mercier, Jacques
AU  - Mercier J
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - United States
TA  - Metabolism
JT  - Metabolism: clinical and experimental
JID - 0375267
RN  - 0 (Blood Glucose)
RN  - 0 (Insulin)
RN  - 33X04XA5AT (Lactic Acid)
RN  - X4W3ENH1CV (Norepinephrine)
RN  - YKH834O4BH (Epinephrine)
SB  - IM
MH  - Adult
MH  - Age Factors
MH  - Blood Glucose
MH  - Calorimetry, Indirect
MH  - Epinephrine/blood
MH  - Exercise Test
MH  - Humans
MH  - Insulin/blood
MH  - Lactic Acid/blood
MH  - *Life Style
MH  - Male
MH  - Middle Aged
MH  - Norepinephrine/blood
MH  - Oxidation-Reduction
MH  - Oxygen Consumption/*physiology
MH  - Physical Exertion/*physiology
MH  - Physical Fitness/physiology
MH  - *Sports
EDAT- 2005/10/29 09:00
MHDA- 2005/12/29 09:00
CRDT- 2005/10/29 09:00
PHST- 2003/09/10 00:00 [received]
PHST- 2004/12/08 00:00 [accepted]
PHST- 2005/10/29 09:00 [pubmed]
PHST- 2005/12/29 09:00 [medline]
PHST- 2005/10/29 09:00 [entrez]
AID - S0026-0495(05)00002-8 [pii]
AID - 10.1016/j.metabol.2004.12.002 [doi]
PST - ppublish
SO  - Metabolism. 2005 Nov;54(11):1411-9. doi: 10.1016/j.metabol.2004.12.002.