Serum, urinary and fecal phosphate changes in athletes during periodic and continuous restriction of muscular activity

Abstract

Continuous hypokinesia (CHK) induces significant electrolyte changes, however, it is not known if periodic hypokinesia (PHK) induces smaller or greater electrolyte changes. Thus, the aim of this study was to measure phosphate (P) changes during PHK and CHK. Studies were done during 30 days pre HK period and during 364 days of PHK and CHK periods. Thirty male athletes were chosen as subjects. They were divided into three groups: unrestricted ambulatory control subjects (UACS), continuously hypokinetic subjects (CHKS) and periodically hypokinetic subjects (PHKS). The CHKS group was maintained under an average running distance of 0.7 km.day-1; while the PHKS group was maintained under an average running distance of 0.7 and 11.7 km.day-1 for five days and two days per week, respectively, and the UACS group was maintained under an average running distance of 11.7 km.day-1. Urinary, fecal and serum P, urinary and serum calcium (Ca) and magnesium (Mg), serum 1,25-dehydroxivitamin D (OH)2 D, intact parathyroid hormone (iPTH), urinary creatinine and physical characteristics and peak oxygen uptake were measured. Serum, urinary and fecal P, serum and urinary Ca and Mg, and urinary creatinine increased significantly (p≤ 0.01), while serum iPTH and 1,25 (OH)2 D decreased significantly (p≤ 0.01) in the CHKS and PHKS groups when compared with the UACS group. Body weight and peak oxygen uptake decreased significantly (p≤ 0.01) in the CHKS group, when compared with the UACS group while body weight increased and peak oxygen uptake decreased significantly (p≤ 0.01) in the PHKS group. The measured parameters changed much faster and much more in the PHKS group than in the CHKS group. The measured parameters did not change significantly in the UACS group when compared with the baseline control values. It was concluded that PHK and CHK induced significant fecal, urinary and serum P changes in endurance trained athletes; however, serum, fecal and urinary P changes appeared much faster and were much greater in the PHKS group than in the CHKS group. Thus prolonged PHK induces much greater P changes than CHK.