Evidence map›Paper›PMID 21461761›Full record

Trial reportEuropean journal of applied physiology2011

No effect of caffeine on exercise performance in high ambient temperature.

Bart Roelands, Luk Buyse, Frank Pauwels, Frans Delbeke, Koen Deventer, Romain Meeusen

Abstract readRandomized Controlled Trial
PubMed Publisher
In one paragraph

Trial report in European journal of applied physiology, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 29 papers, 7 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
29citing papers in PubMed, 7 pooled it
2.6field-weighted citation impact, top 11% 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

29 citing papers in PubMed, 7 syntheses or guidelines pooled it, 70 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Pooled it
  4. Pooled it
  5. Pooled it
  6. Pooled it
  7. Pooled it
  8. Trial
  9. Trial
  10. Trial
  11. Trial
  12. Article
  13. Review
  14. Review
  15. Article
  16. Review
  17. International society of sports nutrition position stand: caffeine and exercise performance.Journal of the International Society of Sports Nutrition · 2021
    Review
  18. Comment on: "Caffeine and Exercise: What Next?"Sports medicine (Auckland, N.Z.) · 2020
    Article
  19. Review
  20. Article
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

6 authors at 2 institutions in 1 country.

Bart RoelandsDepartment of Human Physiology and Sports Medicine, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
Luk Buyse
Frank Pauwels
Frans Delbeke
Koen Deventer
Romain Meeusen
Vrije Universiteit Brussel · BEGhent University · BE

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Caffeine, an adenosine receptor antagonist, has shown to improve performance in normal ambient temperature, presumably via an effect on dopaminergic neurotransmission through the antagonism of adenosine receptors. However, there is very limited evidence from studies that administered caffeine and examined its effects on exercise in the heat. Therefore, we wanted to study the effects of caffeine on performance and thermoregulation in high ambient temperature. Eight healthy trained male cyclists completed two experimental trials (in 30°C) in a double-blind-randomized crossover design. Subjects ingested either placebo (6 mg/kg) or caffeine (6 mg/kg) 1 h prior to exercise. Subjects cycled for 60 min at 55% W (max), immediately followed by a time trial to measure performance. The significance level was set at p < 0.05. Caffeine did not change performance (p = 0.462). Rectal temperature was significantly elevated after caffeine administration (p < 0.036). Caffeine significantly increased B-endorphin plasma concentrations at the end of the time trial (p = 0.032). The present study showed no ergogenic effect of caffeine when administered 1 h before exercise in 30°C. This confirms results from a previous study that examined the effects of caffeine administration on a short (15 min) time trial in 40°C. However, caffeine increased core temperature during exercise. Presumably, the rate of increase in core temperature may have counteracted the ergogenic effects of caffeine. However, other factors such as interindividual differences in response to caffeine and changes in neurotransmitter concentrations might also be responsible for the lack of performance improvement of caffeine in high ambient temperature.

Indexed as

Adultbeta-EndorphinBicyclingBody TemperatureBody Temperature RegulationCaffeineCross-Over StudiesDouble-Blind MethodExerciseHeart RateHot TemperatureHumansMaleYoung Adultbeta-EndorphinCaffeine

Identifiers

PMID21461761
OpenAlexW2011297056

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.