Send to

Choose Destination
Br J Sports Med. 2007 Aug;41(8):523-30; discussion 530. Epub 2007 May 1.

Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions.

Author information

Laboratory of Protein Biochemistry, Federal University of State of Rio de Janeiro, Rio de Janeiro, Brazil.



To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise.


22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo-Yo intermittent recovery test.


Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine.


The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center