Abstract
Caffeine intake improves intense
intermittent exercise performance and reduces muscle interstitial potassium accumulation. J Appl Physiol 111: 1372–1379, 2011. First
published August 11, 2011; doi:10.1152/japplphysiol.01028.2010.—
The effect of oral caffeine ingestion on intense intermittent exercise
performance and muscle interstitial ion concentrations was examined.
The study consists of two studies (S1 and S2). In S1, 12 subjects
completed the Yo-Yo intermittent recovery level 2 (Yo-Yo IR2) test
with prior caffeine (6 mg/kg body wt; CAF) or placebo (PLA) intake.
In S2, 6 subjects performed one low-intensity (20 W) and three
intense (50 W) 3-min (separated by 5 min) one-legged knee-extension
exercise bouts with (CAF) and without (CON) prior caffeine supplementation for determination of muscle interstitial K and Na with
microdialysis. In S1 Yo-Yo IR2 performance was 16% better (P
0.05) in CAF compared with PLA. In CAF, plasma K at the end of
the Yo-Yo IR2 test was 5.2 0.1 mmol/l with no difference between
the trials. Plasma free fatty acids (FFA) were higher (P 0.05) in
CAF than PLA at rest and remained higher (P 0.05) during
exercise. Peak blood glucose (8.0 0.6 vs. 6.2 0.4 mmol/l) and
plasma NH3 (137.2 10.8 vs. 113.4 13.3 mol/l) were also higher
(P 0.05) in CAF compared with PLA. In S2 interstitial K was
5.5 0.3, 5.7 0.3, 5.8 0.5, and 5.5 0.3 mmol/l at the end of
the 20-W and three 50-W periods, respectively, in CAF, which were
lower (P 0.001) than in CON (7.0 0.6, 7.5 0.7, 7.5 0.4, and
7.0 0.6 mmol/l, respectively). No differences in interstitial Na
were observed between CAF and CON. In conclusion, caffeine intake
enhances fatigue resistance and reduces muscle interstitial K during
intense intermittent exercise.
intermittent exercise performance and reduces muscle interstitial potassium accumulation. J Appl Physiol 111: 1372–1379, 2011. First
published August 11, 2011; doi:10.1152/japplphysiol.01028.2010.—
The effect of oral caffeine ingestion on intense intermittent exercise
performance and muscle interstitial ion concentrations was examined.
The study consists of two studies (S1 and S2). In S1, 12 subjects
completed the Yo-Yo intermittent recovery level 2 (Yo-Yo IR2) test
with prior caffeine (6 mg/kg body wt; CAF) or placebo (PLA) intake.
In S2, 6 subjects performed one low-intensity (20 W) and three
intense (50 W) 3-min (separated by 5 min) one-legged knee-extension
exercise bouts with (CAF) and without (CON) prior caffeine supplementation for determination of muscle interstitial K and Na with
microdialysis. In S1 Yo-Yo IR2 performance was 16% better (P
0.05) in CAF compared with PLA. In CAF, plasma K at the end of
the Yo-Yo IR2 test was 5.2 0.1 mmol/l with no difference between
the trials. Plasma free fatty acids (FFA) were higher (P 0.05) in
CAF than PLA at rest and remained higher (P 0.05) during
exercise. Peak blood glucose (8.0 0.6 vs. 6.2 0.4 mmol/l) and
plasma NH3 (137.2 10.8 vs. 113.4 13.3 mol/l) were also higher
(P 0.05) in CAF compared with PLA. In S2 interstitial K was
5.5 0.3, 5.7 0.3, 5.8 0.5, and 5.5 0.3 mmol/l at the end of
the 20-W and three 50-W periods, respectively, in CAF, which were
lower (P 0.001) than in CON (7.0 0.6, 7.5 0.7, 7.5 0.4, and
7.0 0.6 mmol/l, respectively). No differences in interstitial Na
were observed between CAF and CON. In conclusion, caffeine intake
enhances fatigue resistance and reduces muscle interstitial K during
intense intermittent exercise.
| Original language | English |
|---|---|
| Pages (from-to) | 1372-1379 |
| Number of pages | 8 |
| Journal | Journal of Applied Physiology |
| Volume | 111 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 1 Nov 2011 |
Keywords
- fatigue
- potassium
- free fatty acids
- repeated exercise
- muscle ion kinetics
- caffeine