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Pre-exercise acidification induced by ingestion of NH4Cl increases the magnitude of the slow component of VO2 kinetics in humans.
J Physiol Pharmacol. 1998 Sep; 49(3):443-55.JP

Abstract

Five healthy non-smoking men, aged 22.2 +/- 0.8 years (mean SD), VO2 max 50.2 +/- 6.2 ml.min-1.kg-1) performed two 6 minutes constant power output (PO) bouts of cycling at 70 rev.min-1, separated by a 20 minutes of rest. The power output during the first bout of exercise corresponded to 40% VO2max, while the second exercise corresponded to 75% VO2max. The first bout of exercise was performed at a power output below the lactate threshold (LT)--determined during an incremental exercise test. In the second bout of exercise the subjects exercised above the LT. This experimental protocol was performed twice. Once as a control test (test C) and on a separate day, at about 90 minutes after ingestion of 3 mmol.kg-1 BW of NH4Cl (test A). Ingestion of ammonium chloride developed a state of metabolic acidosis. Antecubital venous blood samples taken every one minute of cycling were analysed for pH, HCO-3, BE, pO2, pCO2 and plasma lactate concentration [La]pl. Oxygen uptake was measured continuously using breath by breath system. The obtained acidotic shift of blood acid-base balance was also present throughout the 6 minutes bouts of exercise. No significant difference in VO2 during the exercise corresponding to 40% VO2 max in the test C and the test A was observed. The total oxygen consumed throughout the 6 min cycling at the PO corresponding to 75% of VO2 max was not significantly different in test C and test A (13.532 vs. 13.422 l O2, respectively). The slow component of VO2 kinetics as expressed by the delta VO2(6-3 min) of exercise was significantly higher (p = 0.03) in test A than in test C (183 +/- 97 vs. 106 +/- 53 ml.min-1 O2, respectively). It should be noted that in each subject, the magnitude of the slow component of VO2 kinetics after pre-exercise acidification was consistently higher than in control experiment.

IN CONCLUSION

The original finding of our study is that pre-exercise acidification induced by ingestion of 3 mmol.kg-1 B.W. of NH4Cl was accompanied by a significant increase in the magnitude of the slow component of VO2 kinetics. This is why we postulate that acidosis may play a significant role in the physiological mechanism responsible for the slow component of VO2 kinetics in humans.

Authors+Show Affiliations

Department of Physiology and Biochemistry, AWF, Kraków, Poland. wfzoladz@cyf-kr.edu.plNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9789796

Citation

Zoładź, J, et al. "Pre-exercise Acidification Induced By Ingestion of NH4Cl Increases the Magnitude of the Slow Component of VO2 Kinetics in Humans." Journal of Physiology and Pharmacology : an Official Journal of the Polish Physiological Society, vol. 49, no. 3, 1998, pp. 443-55.
Zoładź J, Duda K, Majerczak J, et al. Pre-exercise acidification induced by ingestion of NH4Cl increases the magnitude of the slow component of VO2 kinetics in humans. J Physiol Pharmacol. 1998;49(3):443-55.
Zoładź, J., Duda, K., Majerczak, J., Emmerich, J., & Domański, J. (1998). Pre-exercise acidification induced by ingestion of NH4Cl increases the magnitude of the slow component of VO2 kinetics in humans. Journal of Physiology and Pharmacology : an Official Journal of the Polish Physiological Society, 49(3), 443-55.
Zoładź J, et al. Pre-exercise Acidification Induced By Ingestion of NH4Cl Increases the Magnitude of the Slow Component of VO2 Kinetics in Humans. J Physiol Pharmacol. 1998;49(3):443-55. PubMed PMID: 9789796.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Pre-exercise acidification induced by ingestion of NH4Cl increases the magnitude of the slow component of VO2 kinetics in humans. AU - Zoładź,J, AU - Duda,K, AU - Majerczak,J, AU - Emmerich,J, AU - Domański,J, PY - 1998/10/28/pubmed PY - 1998/10/28/medline PY - 1998/10/28/entrez SP - 443 EP - 55 JF - Journal of physiology and pharmacology : an official journal of the Polish Physiological Society JO - J Physiol Pharmacol VL - 49 IS - 3 N2 - UNLABELLED: Five healthy non-smoking men, aged 22.2 +/- 0.8 years (mean SD), VO2 max 50.2 +/- 6.2 ml.min-1.kg-1) performed two 6 minutes constant power output (PO) bouts of cycling at 70 rev.min-1, separated by a 20 minutes of rest. The power output during the first bout of exercise corresponded to 40% VO2max, while the second exercise corresponded to 75% VO2max. The first bout of exercise was performed at a power output below the lactate threshold (LT)--determined during an incremental exercise test. In the second bout of exercise the subjects exercised above the LT. This experimental protocol was performed twice. Once as a control test (test C) and on a separate day, at about 90 minutes after ingestion of 3 mmol.kg-1 BW of NH4Cl (test A). Ingestion of ammonium chloride developed a state of metabolic acidosis. Antecubital venous blood samples taken every one minute of cycling were analysed for pH, HCO-3, BE, pO2, pCO2 and plasma lactate concentration [La]pl. Oxygen uptake was measured continuously using breath by breath system. The obtained acidotic shift of blood acid-base balance was also present throughout the 6 minutes bouts of exercise. No significant difference in VO2 during the exercise corresponding to 40% VO2 max in the test C and the test A was observed. The total oxygen consumed throughout the 6 min cycling at the PO corresponding to 75% of VO2 max was not significantly different in test C and test A (13.532 vs. 13.422 l O2, respectively). The slow component of VO2 kinetics as expressed by the delta VO2(6-3 min) of exercise was significantly higher (p = 0.03) in test A than in test C (183 +/- 97 vs. 106 +/- 53 ml.min-1 O2, respectively). It should be noted that in each subject, the magnitude of the slow component of VO2 kinetics after pre-exercise acidification was consistently higher than in control experiment. IN CONCLUSION: The original finding of our study is that pre-exercise acidification induced by ingestion of 3 mmol.kg-1 B.W. of NH4Cl was accompanied by a significant increase in the magnitude of the slow component of VO2 kinetics. This is why we postulate that acidosis may play a significant role in the physiological mechanism responsible for the slow component of VO2 kinetics in humans. SN - 0867-5910 UR - https://www.unboundmedicine.com/medline/citation/9789796/Pre_exercise_acidification_induced_by_ingestion_of_NH4Cl_increases_the_magnitude_of_the_slow_component_of_VO2_kinetics_in_humans_ DB - PRIME DP - Unbound Medicine ER -