Bone mineralization and plasma concentrations of electrolytes in healthy subjects after exposure to hypokinesia and hyperhydration.

The objective of this investigation was to determine bone mineralization and concentrations of electrolytes in blood plasma of physically conditioned volunteers after exposure to hypokinesia (decreased number of steps/day) and daily hyperhydration. The studies were performed on 30 physically conditioned volunteers (mean VO2 max 67 ml/kg-1 x min-1 age range 19-24 years) after exposure to 364 days of hypokinesia (HK). Prior to their exposure to HK all volunteers were long-distance runners who covered on average 10,000 steps per day. All subjects were divided into three equal groups: the 1st group was subjected to HK and consumed daily fluid and salt supplements (water 26 ml/kg body weight and sodium chloride 0.16 g/kg body weight), the 2nd group submitted to pure HK, and the 3rd group continued to engage in long-distance running and served as control. For the hypokinetic effect the 1st and 2nd group of volunteers were restricted to an average of 1000 steps/day. After exposure to HK the changes in bone mineralization and blood plasma concentrations of magnesium and calcium were determined. In hyperhydrated volunteers bone mineralization increased and content of electrolytes in blood plasma decreased, while in hypokinetic volunteers the electrolyte levels increased significantly and bone mineralization decreased significantly. It was concluded that daily fluid an salt supplementation may be used to attenuate changes in bone mineralization and blood plasma concentrations of electrolytes induced by prolonged restriction of motor activity of highly trained athletes.