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Cited by 85Thermoregulation and physiological responsesCoffee research and impactsSports Performance and Training

Caffeine effects on short‐term performance during prolonged exercise in the heat

DEL COSO, JUAN, ESTEVEZ, EMMA, MORA-RODRIGUEZ, RICARDO·2008·Medicine & Science in Sports & Exercise
DOI 10.1249/mss.0b013e3181621336
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Abstract

PURPOSE: To determine the effect of water, carbohydrate, and caffeine ingestion on fatigue during prolonged exercise in the heat. METHODS: Seven endurance-trained cyclists (V O2max = 61 +/- 8 mL.kg.min) pedaled for 120 min at 63% V O2max in a hot-dry environment (36 degrees C; 29% humidity), ingesting either no fluid (NF), water (WAT) to replace 97% fluid losses, the same volume of a 6% carbohydrate-electrolyte solution (CES), or each of these treatments along with ingestion of 6 mg of caffeine per kilogram of body weight (NF + CAFF, WAT + CAFF, and CES + CAFF). At regular intervals during exercise, maximal cycling power (PMAX) was measured. Before and after exercise, maximal voluntary contraction (MVC), voluntary activation (VA), and electrically evoked contractile properties of the quadriceps were determined. RESULTS: Without fluid replacement (NF and NF + CAFF), subjects were dehydrated by 3.8 +/- 0.3%, and rectal temperature reached 39.4 +/- 0.3 degrees C, while it was maintained at 38.7 +/- 0.3 degrees C in trials with rehydration (P < 0.05). Trials with caffeine ingestion increased PMAX by 3% above trials without caffeine (P < 0.05). MVC reductions after exercise were larger with NF (-11 +/- 5%) than for the rest of the trials (P < 0.05). MVC was reduced in WAT compared with CES + CAFF (-6 +/- 4 vs 2 +/- 4%; P < 0.05). However, NF + CAFF maintained MVC at the level of the CES trial. VA showed the same treatment response pattern as MVC. There were no differences in electrically evoked contractile properties among trials. CONCLUSION: During prolonged exercise in the heat, caffeine ingestion (6 mg.kg body weight) maintains MVC and increases PMAX despite dehydration and hyperthermia. When combined with water and carbohydrate, caffeine ingestion increases maximal leg force by increasing VA (i.e., reducing central fatigue).

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Crossref · 10.1249/mss.0b013e3181621336

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  • In a study of endurance-trained cyclists, rehydration with water or carbohydrate-electrolyte solution, with or without caffeine, prevented the significant losses of body fluid, the increase in serum osmolality and the significant rise in core temperature observed with no fluid replacement, with or without caffeine.

    “Rehydration with WAT or CES, with or without caffeine, prevented the significant losses of body fluid, the increase in serum osmolality and the significant rise in core temperature observed with no fluid replacement, with or without caffeine.”

    From Scientific Opinion on the safety of caffeine (2015) · cites this paper as Del Coso et al., 2008

  • In a study of endurance-trained cyclists, no significant differences in fluid losses, serum osmolality or core temperature were observed between the water and carbohydrate-electrolyte groups with caffeine and without caffeine.

    “No significant differences in fluid losses, serum osmolality or core temperature were observed between the WAT and CES groups with caffeine and without caffeine.”

    From Scientific Opinion on the safety of caffeine (2015) · cites this paper as Del Coso et al., 2008

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Authors
DEL COSO, J., ESTEVEZ, E., & MORA-RODRIGUEZ, R.
Venue
Medicine & Science in Sports & Exercise
Publisher
Ovid Technologies (Wolters Kluwer Health)
Published
2008-04
Volume
40
Issue
4
Pages
744-751
ISSN
0195-9131 (ISSN-L)
DOI
10.1249/mss.0b013e3181621336
OpenAlex
W2017754431
Cited by
85
References
30
Citations by year
2026: 1 · 2025: 3 · 2024: 3 · 2022: 4 · 2021: 2 · 2020: 2 · 2019: 4 · 2018: 1 · 2017: 1 · 2016: 4 · 2015: 8 · 2014: 6 · 2013: 8 · 2012: 10
FWCI
6.32
Type
journal article
Language
en
Open access
closed
Locations
  • Medicine & Science in Sports & Exercise (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Physiology › Thermoregulation and physiological responses
  • Health Sciences › Medicine › Pharmacology › Coffee research and impacts
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
Keywords
caffeine ingestion, heat stress, prolonged exercise, dehydration, hyperthermia, central fatigue, muscle fatigue, voluntary activation, maximal voluntary contraction, carbohydrate-electrolyte solution, water intake, rectal temperature, endurance cyclists
MeSH terms
Adult, Bicycling, Body Temperature, Caffeine, Carbohydrates, Dehydration, Double-Blind Method, Exercise Test, Fatigue, Fluid Therapy, Hot Temperature, Humans, Male, Muscle Contraction, Risk Factors, Time Factors, Water, Exercise, Exercise Tolerance, Muscle, Skeletal

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