Evidence map›Paper›PMID 11118510›Full record

ArticleThe Journal of physiology2000

Caffeine ingestion does not alter carbohydrate or fat metabolism in human skeletal muscle during exercise.

T E Graham, J W Helge, D A MacLean, B Kiens, E A Richter

Open access · greenAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in The Journal of physiology, 2000. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 64 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
64citing papers in PubMed, 3 pooled it
3.7field-weighted citation impact, top 7% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

64 citing papers in PubMed, 3 syntheses or guidelines pooled it, 221 citations in OpenAlex.

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  5. An extract from wholeJournal of the International Society of Sports Nutrition · 2026
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  15. The effect of an acute ingestion of Turkish coffee on reaction time and time trial performance.Journal of the International Society of Sports Nutrition · 2015
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4 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 3 institutions in 3 countries.

T E GrahamHuman Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada. terrygra@uoguelph.ca
J W Helge
D A MacLean
B Kiens
E A Richter
University of Copenhagen · DKPennsylvania State University · USUniversity of Guelph · CA

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

This study examined the effect of ingesting caffeine (6 mg kg-1) on muscle carbohydrate and fat metabolism during steady-state exercise in humans. Young male subjects (n = 10) performed 1 h of exercise (70% maximal oxygen consumption (VO2,max)) on two occasions (after ingestion of placebo and caffeine) and leg metabolism was quantified by the combination of direct Fick measures and muscle biopsies. Following caffeine ingestion serum fatty acid and glycerol concentration increased (P< or =0.05) at rest, suggesting enhanced adipose tissue lipolysis. In addition circulating adrenaline concentration was increased (P< or =0.05) at rest following caffeine ingestion and this, as well as leg noradrenaline spillover, was elevated (P< or =0.05) above placebo values during exercise. Caffeine resulted in a modest increase (P< or =0.05) in leg vascular resistance, but no difference was found in leg blood flow. Arterial lactate and glucose concentrations were increased (P< or =0.05) by caffeine, while the rise in plasma potassium was dampened (P< or =0.05). There were no differences in respiratory exchange ratio or in leg glucose uptake, net muscle glycogenolysis, leg lactate release or muscle lactate, or glucose 6-phosphate concentration. Similarly there were no differences between treatments in leg fatty acid uptake, glycerol release or muscle acetyl CoA concentration. These findings indicate that caffeine ingestion stimulated the sympathetic nervous system but did not alter the carbohydrate or fat metabolism in the monitored leg. Other tissues must have been involved in the changes in circulating potassium, fatty acids, glucose and lactate.

Indexed as

Carbohydrate MetabolismAdministration, OralAdultCaffeineCatecholaminesCentral Nervous System StimulantsExerciseFatsHeartHumansLungMaleMuscle, SkeletalPotassiumCaffeineCatecholaminesCentral Nervous System StimulantsFatsPotassium

Identifiers

PMID11118510
PMCPMC2270224
OpenAlexW2105174204

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.