Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude

C. S. Fulco, K. W. Kambis, A. L. Friedlander, P. B. Rock, S. R. Muza, A. Cymerman

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Carbohydrate supplementation (CHOS) typically improves prolonged time-trial (TT) performance at sea level (SL). This study determined whether CHOS also improves TT performance at high altitude (ALT; 4,300 M) despite increased hypoxemia and while in negative energy balance (∼1,250 kcal/day). Two groups of fasting, fitness-matched men performed a 720-kJ cycle TT at SL and while living at ALT on days 3 (ALT3) and 10 (ALT10). Eight men drank a 10% carbohydrate solution (0.175 g/kg body wt) and eight drank a placebo (PLA; double blind) at the start of and every 15 min of the TT. Blood glucose during each TT was higher (P < 0.05) for CHOS than for PLA. At SL, TT duration (∼59 min) and watts (∼218 or ∼61% of peak watts; %SL Wpeak) were similar for both groups. At ALT, the TT was longer for both groups (P < 0.01) but was shorter for CHOS than for PLA on ALT3 (means ± SE: 80 ± 7 vs. 105 ± 9 min; P < 0.01) and ALT10 (77 ± 7 vs. 90 ± 5 min; P < 0.01). At ALT, %SL Wpeak was reduced (P < 0.01) with the reduction on ALT3 being larger for PLA (to 33 ± 3%) than for CHOS (to 43 ± 2%; P < 0.05). On ALT3, O2 saturation fell similarly from 84 ± 2% at rest to 73 ± 1% during the TT for both groups (P < 0.05), and on ALT10 O2 saturation fell more (P < 0.02) for CHOS (91 ± 1 to 76 ± 2%) than for PLA (90 ± 1 to 81 ± 1%). %SL Wpeak and O2 saturation were inversely related during the TT for both groups at ALT (r ≥ -0.76; P ≤ 0.03). It was concluded that, despite hypoxemia exacerbated by exercise, CHOS greatly improved TT performance at ALT in which there was a negative energy balance.

Original languageEnglish
Pages (from-to)867-876
Number of pages10
JournalJournal of Applied Physiology
Volume99
Issue number3
DOIs
StatePublished - 1 Sep 2005

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Carbohydrates
Oceans and Seas
Blood Glucose
Fasting
Placebos

Keywords

  • Endurance performance
  • Ergogenic
  • Glucose
  • Hypoxemia
  • Prolonged exercise

Cite this

Fulco, C. S. ; Kambis, K. W. ; Friedlander, A. L. ; Rock, P. B. ; Muza, S. R. ; Cymerman, A. / Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude. In: Journal of Applied Physiology. 2005 ; Vol. 99, No. 3. pp. 867-876.
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title = "Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude",
abstract = "Carbohydrate supplementation (CHOS) typically improves prolonged time-trial (TT) performance at sea level (SL). This study determined whether CHOS also improves TT performance at high altitude (ALT; 4,300 M) despite increased hypoxemia and while in negative energy balance (∼1,250 kcal/day). Two groups of fasting, fitness-matched men performed a 720-kJ cycle TT at SL and while living at ALT on days 3 (ALT3) and 10 (ALT10). Eight men drank a 10{\%} carbohydrate solution (0.175 g/kg body wt) and eight drank a placebo (PLA; double blind) at the start of and every 15 min of the TT. Blood glucose during each TT was higher (P < 0.05) for CHOS than for PLA. At SL, TT duration (∼59 min) and watts (∼218 or ∼61{\%} of peak watts; {\%}SL Wpeak) were similar for both groups. At ALT, the TT was longer for both groups (P < 0.01) but was shorter for CHOS than for PLA on ALT3 (means ± SE: 80 ± 7 vs. 105 ± 9 min; P < 0.01) and ALT10 (77 ± 7 vs. 90 ± 5 min; P < 0.01). At ALT, {\%}SL Wpeak was reduced (P < 0.01) with the reduction on ALT3 being larger for PLA (to 33 ± 3{\%}) than for CHOS (to 43 ± 2{\%}; P < 0.05). On ALT3, O2 saturation fell similarly from 84 ± 2{\%} at rest to 73 ± 1{\%} during the TT for both groups (P < 0.05), and on ALT10 O2 saturation fell more (P < 0.02) for CHOS (91 ± 1 to 76 ± 2{\%}) than for PLA (90 ± 1 to 81 ± 1{\%}). {\%}SL Wpeak and O2 saturation were inversely related during the TT for both groups at ALT (r ≥ -0.76; P ≤ 0.03). It was concluded that, despite hypoxemia exacerbated by exercise, CHOS greatly improved TT performance at ALT in which there was a negative energy balance.",
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Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude. / Fulco, C. S.; Kambis, K. W.; Friedlander, A. L.; Rock, P. B.; Muza, S. R.; Cymerman, A.

In: Journal of Applied Physiology, Vol. 99, No. 3, 01.09.2005, p. 867-876.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Carbohydrate supplementation improves time-trial cycle performance during energy deficit at 4,300-m altitude

AU - Fulco, C. S.

AU - Kambis, K. W.

AU - Friedlander, A. L.

AU - Rock, P. B.

AU - Muza, S. R.

AU - Cymerman, A.

PY - 2005/9/1

Y1 - 2005/9/1

N2 - Carbohydrate supplementation (CHOS) typically improves prolonged time-trial (TT) performance at sea level (SL). This study determined whether CHOS also improves TT performance at high altitude (ALT; 4,300 M) despite increased hypoxemia and while in negative energy balance (∼1,250 kcal/day). Two groups of fasting, fitness-matched men performed a 720-kJ cycle TT at SL and while living at ALT on days 3 (ALT3) and 10 (ALT10). Eight men drank a 10% carbohydrate solution (0.175 g/kg body wt) and eight drank a placebo (PLA; double blind) at the start of and every 15 min of the TT. Blood glucose during each TT was higher (P < 0.05) for CHOS than for PLA. At SL, TT duration (∼59 min) and watts (∼218 or ∼61% of peak watts; %SL Wpeak) were similar for both groups. At ALT, the TT was longer for both groups (P < 0.01) but was shorter for CHOS than for PLA on ALT3 (means ± SE: 80 ± 7 vs. 105 ± 9 min; P < 0.01) and ALT10 (77 ± 7 vs. 90 ± 5 min; P < 0.01). At ALT, %SL Wpeak was reduced (P < 0.01) with the reduction on ALT3 being larger for PLA (to 33 ± 3%) than for CHOS (to 43 ± 2%; P < 0.05). On ALT3, O2 saturation fell similarly from 84 ± 2% at rest to 73 ± 1% during the TT for both groups (P < 0.05), and on ALT10 O2 saturation fell more (P < 0.02) for CHOS (91 ± 1 to 76 ± 2%) than for PLA (90 ± 1 to 81 ± 1%). %SL Wpeak and O2 saturation were inversely related during the TT for both groups at ALT (r ≥ -0.76; P ≤ 0.03). It was concluded that, despite hypoxemia exacerbated by exercise, CHOS greatly improved TT performance at ALT in which there was a negative energy balance.

AB - Carbohydrate supplementation (CHOS) typically improves prolonged time-trial (TT) performance at sea level (SL). This study determined whether CHOS also improves TT performance at high altitude (ALT; 4,300 M) despite increased hypoxemia and while in negative energy balance (∼1,250 kcal/day). Two groups of fasting, fitness-matched men performed a 720-kJ cycle TT at SL and while living at ALT on days 3 (ALT3) and 10 (ALT10). Eight men drank a 10% carbohydrate solution (0.175 g/kg body wt) and eight drank a placebo (PLA; double blind) at the start of and every 15 min of the TT. Blood glucose during each TT was higher (P < 0.05) for CHOS than for PLA. At SL, TT duration (∼59 min) and watts (∼218 or ∼61% of peak watts; %SL Wpeak) were similar for both groups. At ALT, the TT was longer for both groups (P < 0.01) but was shorter for CHOS than for PLA on ALT3 (means ± SE: 80 ± 7 vs. 105 ± 9 min; P < 0.01) and ALT10 (77 ± 7 vs. 90 ± 5 min; P < 0.01). At ALT, %SL Wpeak was reduced (P < 0.01) with the reduction on ALT3 being larger for PLA (to 33 ± 3%) than for CHOS (to 43 ± 2%; P < 0.05). On ALT3, O2 saturation fell similarly from 84 ± 2% at rest to 73 ± 1% during the TT for both groups (P < 0.05), and on ALT10 O2 saturation fell more (P < 0.02) for CHOS (91 ± 1 to 76 ± 2%) than for PLA (90 ± 1 to 81 ± 1%). %SL Wpeak and O2 saturation were inversely related during the TT for both groups at ALT (r ≥ -0.76; P ≤ 0.03). It was concluded that, despite hypoxemia exacerbated by exercise, CHOS greatly improved TT performance at ALT in which there was a negative energy balance.

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KW - Ergogenic

KW - Glucose

KW - Hypoxemia

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