BACKGROUND: Loss of body mass during a 24-h run was considered to be a result of dehydration. AIMS: We intended to quantify the decrease in body mass as a loss in fat mass or skeletal muscle mass and to quantify the change in hydration status. METHODS: Body mass, fat mass, skeletal muscle mass, haematocrit, plasma sodium and urinary specific gravity were measured in 15 ultra-marathoners in a 24-h run. RESULTS: Body mass decreased by 2.2 kg (p = 0.0009) and fat mass decreased by 0.5 kg (p = 0.0084). The decrease in body mass correlated to the decrease in fat mass (r = 0.72, p = 0.0024). Urinary specific gravity increased from 1.012 to 1.022 g/mL (p = 0.0005). CONCLUSIONS: The decrease in body mass and the increase in urinary specific gravity indicate dehydration. The decrease in body mass was correlated to the decrease in fat mass and therefore not only due to dehydration.
BACKGROUND: Loss of body mass during a 24-h run was considered to be a result of dehydration. AIMS: We intended to quantify the decrease in body mass as a loss in fat mass or skeletal muscle mass and to quantify the change in hydration status. METHODS: Body mass, fat mass, skeletal muscle mass, haematocrit, plasma sodium and urinary specific gravity were measured in 15 ultra-marathoners in a 24-h run. RESULTS: Body mass decreased by 2.2 kg (p = 0.0009) and fat mass decreased by 0.5 kg (p = 0.0084). The decrease in body mass correlated to the decrease in fat mass (r = 0.72, p = 0.0024). Urinary specific gravity increased from 1.012 to 1.022 g/mL (p = 0.0005). CONCLUSIONS: The decrease in body mass and the increase in urinary specific gravity indicate dehydration. The decrease in body mass was correlated to the decrease in fat mass and therefore not only due to dehydration.
Authors: L A Popowski; R A Oppliger; G Patrick Lambert; R F Johnson; A Kim Johnson; C V Gisolf Journal: Med Sci Sports Exerc Date: 2001-05 Impact factor: 5.411
Authors: Katja Weiss; David Valero; Elias Villiger; Volker Scheer; Mabliny Thuany; Ivan Cuk; Thomas Rosemann; Beat Knechtle Journal: Front Physiol Date: 2022-06-14 Impact factor: 4.755
Authors: Beat Knechtle; Sabrina Baumgartner; Patrizia Knechtle; Christoph Alexander Rüst; Thomas Rosemann; Raúl Bescós Journal: Open Access J Sports Med Date: 2012-10-25