Changes in Blood pH and Ammonia Following Repeat Sprint Performance

Abstract

The relationship between relative intensity and changes in blood pH and ammonia are not well characterized. PURPOSE: The primary aim of the study was to determine how changes in relative exercise intensity following repeat sprint performance affect changes in blood pH and blood ammonia concentrations. METHODS: Healthy college- age males (n = 12) completed completed one 30 second Wingate cycle sprint test as a familiarization trial. A minimum of 48 hours after the familiarization trial, participants returned to the lab. Resting venous and capillary blood samples were obtained to determine blood ammonia, pH, and lactate levels. Participants then completed 3 Wingate sprint tests, separated by 5 minutes each. Finger capillary blood was immediately obtained after each test to determine lactate and pH values. After the final test, an additional venous blood sample was obtained to determine blood ammonia values. RESULTS: Data are shown as 1st vs. 2nd vs. 3rd tests, respectively. There was a significant effect for time for peak power (750.08 ± 39.55 vs. 675.42 ± 30.01 vs. 615.60 ± 37.72 Watts); F = 4.66, p = 0.05, mean power (632.67 ± 30.71 vs. 561.25 ± 22.16 vs. 524.40 ± 26.46 Watts); F = 5.04, p = 0.04, pH (7.72 ± 0.01 vs. 7.63 ± 0.02 vs. 7.62 ± 0.02); F = 70.18, p < 0.01, and lactate (12.36 ± 1.14 vs. 14.10 ± 1.13 vs. 16.95 ± 1.22 mg/dL); F= 42.02, p < 0.01. Blood ammonia values did increase from pre- to post-exercise (0.33 ± 0.09 vs. 1.07 ± 0.22 mg/dl); t = 3.62, p < 0.01, but there was no correlation between post-exercise ammonia values and change in peak or mean power. There was a weak, but significant correlation between change in peak power and change in pH (R2 = 0.34, p = 0.05) and change in mean power and change in pH (R2 = 0.44, p = 0.02). CONCLUSIONS: Greater reductions in peak power and mean power correlated with change in blood pH, but not post-exercise ammonia values.