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Effect of different cycling frequencies during incremental exercise on the venous plasma potassium concentration in humans.
Physiol Res. 2002; 51(6):581-6.PR

Abstract

The effect of different muscle shortening velocity was studied during cycling at a pedalling rate of 60 and 120 rev.min(-1) on the [K+]v in humans. Twenty-one healthy young men aged 22.5+/-2.2 years, body mass 72.7+/-6.4 kg, VO2 max 3.720+/-0.426 l. min(-1), performed an incremental exercise test until exhaustion. The power output increased by 30 W every 3 min, using an electrically controlled ergometer Ergoline 800 S (see Zoladz et al. J. Physiol. 488: 211-217, 1995). The test was performed twice: once at a cycling frequency of 60 rev.min(-1) (test A) and a few days later at a frequency of 120 rev. min(-1) (test B). At rest and at the end of each step (i.e. the last 15 s) antecubital venous blood samples for [K+]p were taken. Gas exchange variables were measured continuously (breath-by-breath) using Oxycon Champion Jaeger. The pre-exercise [K+]v in both tests was not significantly different amounting to 4.24+/-0.36 mmol.l(-1) in test A, and 4.37+/-0.45 mmol.l(-1) in test B. However, the [K+]p during cycling at 120 rev. min(-1) was significantly higher (p<0.001, ANOVA for repeated measurements) at each power output when compared to cycling at 60 rev.min(-1). The maximal power output reached 293+/-31 W in test A which was significantly higher (p<0.001) than in test B, which amounted to 223+/-40 W. The VO2max values in both tests reached 3.720+/-0.426 l. min(-1) vs 3.777+/-0.514 l. min(-1). These values were not significantly different. When the [K+]v was measured during incremental cycling exercise, a linear increase in [K+]v was observed in both tests. However, a significant (p<0.05) upward shift in the [K+]v and a % VO2max relationship was detected during cycling at 120 rev.min(-1). The [K+]v measured at the VO2max level in tests A and B amounted to 6.00+/-0.47 mmol.l-1 vs 6.04+/-0.41 mmol.l-1, respectively. This difference was not significant. It may thus be concluded that: a) generation of the same external mechanical power output during cycling at a pedalling rate of 120 rev.min(-1) causes significantly higher [K+]v changes than when cycling at 60 rev.min(-1), b) the increase of venous plasma potassium concentration during dynamic incremental exercise is linearly related to the metabolic cost of work expressed by the percentage of VO2max (increase as reported previously by Vollestad et al. J. Physiol. 475: 359-368, 1994), c) there is a tendency towards upward up shift in the [K+]v and % VO2max relation during cycling at 120 rev.min(-1) when compared to cycling at 60 rev.min(-1).

Authors+Show Affiliations

Department of Muscle Physiology, AWF-Krakow, Krakow, Poland. wfzoladz@cyf-kr.edu.plNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

12511181

Citation

Zoladz, J A., et al. "Effect of Different Cycling Frequencies During Incremental Exercise On the Venous Plasma Potassium Concentration in Humans." Physiological Research, vol. 51, no. 6, 2002, pp. 581-6.
Zoladz JA, Duda K, Majerczak J, et al. Effect of different cycling frequencies during incremental exercise on the venous plasma potassium concentration in humans. Physiol Res. 2002;51(6):581-6.
Zoladz, J. A., Duda, K., Majerczak, J., & Thor, P. (2002). Effect of different cycling frequencies during incremental exercise on the venous plasma potassium concentration in humans. Physiological Research, 51(6), 581-6.
Zoladz JA, et al. Effect of Different Cycling Frequencies During Incremental Exercise On the Venous Plasma Potassium Concentration in Humans. Physiol Res. 2002;51(6):581-6. PubMed PMID: 12511181.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of different cycling frequencies during incremental exercise on the venous plasma potassium concentration in humans. AU - Zoladz,J A, AU - Duda,K, AU - Majerczak,J, AU - Thor,P, PY - 2003/1/4/pubmed PY - 2003/8/30/medline PY - 2003/1/4/entrez SP - 581 EP - 6 JF - Physiological research JO - Physiol Res VL - 51 IS - 6 N2 - The effect of different muscle shortening velocity was studied during cycling at a pedalling rate of 60 and 120 rev.min(-1) on the [K+]v in humans. Twenty-one healthy young men aged 22.5+/-2.2 years, body mass 72.7+/-6.4 kg, VO2 max 3.720+/-0.426 l. min(-1), performed an incremental exercise test until exhaustion. The power output increased by 30 W every 3 min, using an electrically controlled ergometer Ergoline 800 S (see Zoladz et al. J. Physiol. 488: 211-217, 1995). The test was performed twice: once at a cycling frequency of 60 rev.min(-1) (test A) and a few days later at a frequency of 120 rev. min(-1) (test B). At rest and at the end of each step (i.e. the last 15 s) antecubital venous blood samples for [K+]p were taken. Gas exchange variables were measured continuously (breath-by-breath) using Oxycon Champion Jaeger. The pre-exercise [K+]v in both tests was not significantly different amounting to 4.24+/-0.36 mmol.l(-1) in test A, and 4.37+/-0.45 mmol.l(-1) in test B. However, the [K+]p during cycling at 120 rev. min(-1) was significantly higher (p<0.001, ANOVA for repeated measurements) at each power output when compared to cycling at 60 rev.min(-1). The maximal power output reached 293+/-31 W in test A which was significantly higher (p<0.001) than in test B, which amounted to 223+/-40 W. The VO2max values in both tests reached 3.720+/-0.426 l. min(-1) vs 3.777+/-0.514 l. min(-1). These values were not significantly different. When the [K+]v was measured during incremental cycling exercise, a linear increase in [K+]v was observed in both tests. However, a significant (p<0.05) upward shift in the [K+]v and a % VO2max relationship was detected during cycling at 120 rev.min(-1). The [K+]v measured at the VO2max level in tests A and B amounted to 6.00+/-0.47 mmol.l-1 vs 6.04+/-0.41 mmol.l-1, respectively. This difference was not significant. It may thus be concluded that: a) generation of the same external mechanical power output during cycling at a pedalling rate of 120 rev.min(-1) causes significantly higher [K+]v changes than when cycling at 60 rev.min(-1), b) the increase of venous plasma potassium concentration during dynamic incremental exercise is linearly related to the metabolic cost of work expressed by the percentage of VO2max (increase as reported previously by Vollestad et al. J. Physiol. 475: 359-368, 1994), c) there is a tendency towards upward up shift in the [K+]v and % VO2max relation during cycling at 120 rev.min(-1) when compared to cycling at 60 rev.min(-1). SN - 0862-8408 UR - https://www.unboundmedicine.com/medline/citation/12511181/Effect_of_different_cycling_frequencies_during_incremental_exercise_on_the_venous_plasma_potassium_concentration_in_humans_ L2 - http://www.biomed.cas.cz/physiolres/pdf/51/51_581.pdf DB - PRIME DP - Unbound Medicine ER -