Kjeldsen K
Department of Medicine B 2142 (Cardiology), Rigshospitalet, University of Copenhagen.
Can J Sport Sci. 1991 Mar;16(1):33-9.
During exercise, potassium leaks out of muscle cells and interstitial potassium concentration may rise to 15 mmol/l. Potassium is then in part transported back to the cells by the Na,K-pump. The leak of potassium from working human muscles can be calculated to 15 mumol/g/min. Human muscles contain 300 pmol/g wet weight Na,K-pumps and have a maximum capacity for potassium uptake of 5 mumol/g/min. At rest only a small percentage is used, but during maximum stimulation the entire capacity can probably be used. During exercise, total potassium leakage from the human muscle pool is 400 mmol/min and maximum active reuptake capacity is 100 mmol/min. ECV contains only 50 mmol potassium. During heavy exercise the capacity for active potassium uptake in muscle pool may be exceeded and interstitial potassium equilibrates with plasma potassium, which then may rise to 10 mmol/l. Training can decrease the rise in plasma potassium during exercise by 0.2-0.5 mmol/l. Variation in muscle Na,K-pump concentration may be associated with changed plasma potassium homeostasis during exercise, which if disadvantageous may be dangerous to the heart.
运动期间，钾从肌肉细胞中泄漏出来，间质钾浓度可能升至15毫摩尔/升。然后，一部分钾通过钠钾泵被转运回细胞。据计算，工作中的人体肌肉钾泄漏量为15微摩尔/克/分钟。人体肌肉每克湿重含有300皮摩尔钠钾泵，钾摄取的最大能力为5微摩尔/克/分钟。在静息状态下，只有一小部分被利用，但在最大刺激时，可能会利用全部能力。运动期间，人体肌肉库的总钾泄漏量为400毫摩尔/分钟，最大主动再摄取能力为100毫摩尔/分钟。细胞外液仅含有50毫摩尔钾。在剧烈运动期间，肌肉库中主动摄取钾的能力可能会被超过，间质钾与血浆钾达到平衡，血浆钾随后可能升至10毫摩尔/升。训练可使运动期间血浆钾的升高降低0.2 - 0.5毫摩尔/升。肌肉钠钾泵浓度的变化可能与运动期间血浆钾稳态的改变有关，若这种改变不利，则可能对心脏造成危险。
