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Changes in arterial plasma potassium and ventilation during exercise in man
D J Paterson1, P A Robbins, J Conway
1University Laboratory of Physiology, Oxford, U.K.
Respiration Physiology
|December 1, 1989
Summary
Exercise increases arterial plasma potassium ( [K+]a), which closely mirrors ventilation (VE) changes. This suggests exercise-induced hyperkalemia may help control breathing during physical activity.
Area of Science:
- Exercise Physiology
- Cardiovascular Physiology
- Respiratory Physiology
Background:
- Hyperkalemia (high blood potassium) is known to increase ventilation in anesthetized animals.
- Arterial chemoreceptors are sensitive to potassium levels and play a role in regulating breathing.
Purpose of the Study:
- To investigate the relationship between arterial plasma potassium levels and ventilation in humans during exercise.
- To determine if exercise-induced hyperkalemia contributes to the control of breathing.
Main Methods:
- Six healthy male volunteers performed sub-maximal (100 W) and maximal (sprint ~350 W) exercise on a cycle ergometer.
- Ventilation (VE) was measured breath-by-breath.
- Arterial blood was sampled to measure plasma potassium ([K+]a) and base excess.
Main Results:
- Arterial plasma potassium ([K+]a) levels closely mirrored ventilation (VE) changes during exercise and recovery.
- During sub-maximal exercise, [K+]a increased from 4 mM to 5 mM.
- During maximal sprint exercise, [K+]a increased to approximately 7 mM.
- Base excess changes did not correlate with VE, peaking after exercise cessation when [K+]a and VE were decreasing.
Conclusions:
- The observed increases in arterial plasma potassium during exercise are likely sufficient to stimulate arterial chemoreceptors.
- The strong temporal correlation between [K+]a and VE suggests that exercise-induced hyperkalemia may play a role in regulating breathing during physical exertion.