Measurement of potassium absorption during hypokinesia in potassium supplemented and unsupplemented healthy subjects

Muscle potassium and potassium losses during hypokinesia in healthy subjects

Hypokinesia (HK) induces electrolyte losses in electrolyte-deficient tissue, yet the mechanisms of electrolyte losses in electrolyte-deficient tissue remain unknown. Mechanisms of electrolyte deposition could be involved. To determine the effect of prolonged HK on potassium (K+) deposition were measured muscle K+ content and K+ losses. Studies were conducted on 20 physically healthy male volunteers during 30 days pre-experimental period and 364 days experimental period. Subjects were equally divided into two groups: control subjects (CS) and experimental subjects (ES). The CS group was run average distances of 9.8±1.7 km day(-1) and the ES group was walked average distances of 2.7±0.6 km day(-1). Muscle K+ content decreased (p<0.05) and plasma K+ concentration, and K+ losses in urine and feces increased (p<0.05) in the ES group compared to their pre-experimental level and the values in their respective CS group. Muscle K+ content, plasma K+ level, and urine and fecal K+ losses did not show any changes in the CS group compared to their pre-experimental values. The conclusion was that K+ losses in K+-deficient muscle of healthy subjects could have been attributable to the less efficient K+ deposition inherently to prolonged HK.

Mechanism of sodium loss with muscle sodium deficiency in sodium supplemented and unsupplemented subjects during hypokinesia

BACKGROUND

This study aims at showing the effect of hypokinesia (HK) on sodium (Na+) loss with different muscle Na+ deficiency and different Na+ intake. Muscle Na+ content, plasma Na+ level and Na+ loss with and without Na+ supplementation were measured.

METHODS

This study was conducted on 40 healthy male volunteers during a pre-experimental and an experimental period. Subjects were equally divided into four groups: unsupplemented active control subjects (UACS), unsupplemented hypokinetic subjects (UHKS), supplemented active control subjects (SACS) and supplemented hypokinetic subjects (SHKS). A daily supplementation of 3.21 mmol of sodium chloride (NaCl) per kg body weight was given to subjects in the SACS and SHKS groups.

RESULTS

Muscle Na+ content levels decreased and plasma Na+ levels, and levels of Na+ loss in urine and feces increased (p<0.05) in the SHKS and UHKS groups compared to their pre-experimental values and the values in the respective active control groups (SACS and UACS). However, muscle Na+ content levels decreased more (p<0.05), and plasma Na+ levels and levels of Na+ loss in urine and feces increased more (p<0.05) in the SHKS group than in the UHKS group.

CONCLUSIONS

The greater muscle Na+ deficiency with higher than lower Na+ consumption shows that the risk of greater muscle Na+ deficiency is directly related to Na+ consumption. The higher Na+ loss with higher than lower muscle Na+ deficiency shows that the risk of greater muscle Na+ loss is directly related to muscle Na+ deficiency. It is concluded that muscle Na+ deficiency is more evident when Na+ consumption is higher and that muscle Na+ loss was more exacerbated with higher than lower muscle Na+ deficiency indicating that during prolonged HK the muscle Na+ deficiency is due to the inability of the body to use Na+, but not to Na+ shortage in diet.