Blood biochemical changes in trained subjects during prolonged restriction of physical activity and chronic hyperhydration.

The objective of this investigation was to determine the effect of daily fluid and salt supplementation on biochemical changes in the serum of endurance trained athletes after exposure to hypokinesia (decreased number of steps from 15,000 to 1000 steps/day). The studies were performed after exposure to 364 days of hypokinesia on 18 long-distance runners aged 19-24 years who had a V02 max of 67.5 ml/kg/min. The volunteers were divided into three equal groups: The 1st group underwent a normal ambulatory life (control subjects), the 2nd group was placed under continuous restriction of motor activity, and the 3rd group was kept under continuous restriction of motor activity whilst consuming daily supplements of 26 ml water/kg body weight and 0.16 g sodium chloride/kg body weight. For hypokinesia the number of steps taken per day by the volunteers in groups 2 and 3 were restricted to an average of 1000. During the hypokinetic period of 364 days and posthypokinetic period of 30 days urea, glucose, acid-soluble phosphorus, inorganic phosphorus, cholesterol (low-density and high-density lipoprotein) and phospholipids were measured at predetermined intervals. During the hypokinetic period in hyperhydrated volunteers urea, cholesterol, phospholipids, inorganic phosphorus and acid soluble phosphorus decreased, while glucose increased. In hypokinetic volunteers a significant increase in urea, cholesterol, phospholipids, inorganic phosphorus and acid soluble phosphorus, and a significant decrease in glucose was demonstrated. During the posthypokinetic period these biochemical changes normalized in both hypokinetic and hyperhydrated volunteers. It is concluded that daily fluid and salt supplementation may effectively counteract changes in blood biochemistry in endurance trained subjects during prolonged restriction of physical activity.