Impact Of Partial And Complete Fluid Restriction On Inflammatory Biomarkers.

Limited evidence exists examining the manipulation of total body water on inflammatory biomarkers in free-living emerging adults. PURPOSE: The purpose of this study was to investigate the acute effects of partial and full fluid restriction on inflammatory biomarkers in males and females. METHODS: Thirty-one participants (42% female; age, 23±4 y; mass, 78.2±17.3 kg; height, 173.2±9.9 cm; body fat, 18.2±8.7%) provided a 24 h measure of urine volume (UVOL) and urine osmolality (UOSM), 24 h dietary and fluid intake record, and fasted blood draw for two consecutive days. Following measure of nude body mass (NBM) and blood draw on day 1, participants underwent a 2 h sauna exposure (41°C, 50% RH) and were randomly assigned to one of three groups; control (CON) where females and males consumed 2.0 and 2.5L of water, respectively, partial fluid restriction (PART) where water consumption matched sauna sweat losses, and full fluid restriction (FULL) where participants were restricted from consuming fluids prior to day 2. Blood samples were analyzed for c-reactive protein (CRP), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), interferon gamma (IFN-y), tumor necrosis factor alpha (TNF-a) and copeptin, a surrogate for arginine vasopressin. RESULTS: On day 2, percent body mass loss in PART (MD [95%CI]; 1.2% [0.2, 2.1], p=0.013) and FULL (1.4% [0.45, 2.5], p=0.004) were significantly greater than CON (0.0±0.5%). Higher UOSM (p=0.001) and copeptin (p<0.001), and lower UVOL(P=0.008) were observed in PART and FULL compared to CON. CRP was significantly lower in CON (estimate [95%CI]; - 7.35 pg/mL [-4.81, -13.13], p=0.011) than PART, however there were no differences between CON (1.82±1.55 pg/mL) and FULL (3.93±6.17 pg/mL, p>005). IL-8 was significantly greater in FULL (estimate, 3.12 pg/mL [0.49, 5.72], p=0.021) than PART. There were no differences in IL-6, IL-10, IFN-y, or TNF-a between groups (p>0.05). CONCLUSIONS: Partial and full fluid restriction over 24 h produced significant changes in circulating concentrations of CRP and IL-8, however, these differences were not consistent between hydration groups. Twenty-four-hour changes in total fluid intake eliciting mild hypohydration (<1.5% body mass loss) may be insufficient to cause a sustained systemic inflammatory response in free-living emerging adults. [ABSTRACT FROM AUTHOR]