DAILY HYPERHYDRATION EFFECT ON ELECTROLYTE DEFICIENCY OF ENDURANCE-TRAINED SUBJECTS DURING PROLONGED HYPOKINESIA

The aim of this study was to evaluate the effect of a daily intake of fluid and salt supplementation (FSS) on the deficiency of electrolytes , which is characterized by higher rather than lower plasma concentrat ion of electrolytes during prolonged hypokinesia (HK) (decreased numbe r of km taken per day). Forty long distance runners aged 22-25 yr with a peak V0(2) 65.4 mL min(-1) kg(-1) with an average 14.2 km d running distance were selected as subjects. They were equally divided into fo ur groups: 1) unsupplemented control subjects (UCS); 2) unsupplemented hypokinetic subjects (UHS); 3) supplemented hypokinetic subjects (SHS ), and 4) supplemented control subjects (SCS). During the investigatio n of 364 d, groups 2 and 3 maintained an average running distance of l ess than 4.7 km per day, groups 1 and 4 did not experience any modific ation in their normal training routines and diets. During the preexper imental period of 60 d and during the experimental period of 364 d uri nary excretion of electrolytes and concentrations of sodium, potassium , calcium, and magnesium in plasma were determined. Whole blood hemogl obin, hematocrit index, plasma osmolality, and plasma protein concentr ation were measured. In the UHS plasma concentration of electrolytes a nd urinary excretion thereof, fluid elimination, hematocrit, whole blo od hemoglobin, plasma osmolality, and plasma protein concentration inc reased significantly (p < 0.05) when compared with the UCS, SCS, and S HS groups. In the SHS plasma concentration of electrolytes and urinary excretion thereof, fluid excretion, whole blood hemoglobin, hematocri t, plasma osmolality, and plasma protein concentration decreased when compared with the UHS and increased insignificantly when compared with the UCS and SCS groups. If was concluded that FSS may be used to prev ent or minimize electrolyte deficiency in endurance-trained volunteers during prolonged restriction of muscular activity.