Effects of a 14-Day Hydration Intervention on Individuals with Habitually Low Fluid Intake.
Journal:
Annals of nutrition & metabolism
PMID:
33780930
Abstract
BACKGROUND: Debate continues over whether or not individuals with low total water intake (TWI) are in a chronic fluid deficit (i.e., low total body water) [1 ]. When women with habitually low TWI (1.6 ± 0.5 L/day) increased their fluid intake (3.5 ± 0.1 L/day) for 4 days 24-h urine osmolality decreased, but there was no change in body weight, a proxy for total body water (TBW) [2 ]. In a small (n = 5) study of adult men, there were no observable changes in TBW, as measured by bioelectrical impedance, after increasing TWI for 4 weeks [3 ]. However, body weight increased and salivary osmolality decreased indicating that the study may have been underpowered to detect changes in TBW. Further, no studies to date have measured changes in blood volume (BV) when TWI is increased.