Francisco J Amaro-Gahete1,2, Guillermo Sanchez-Delgado2, Ignacio Ara3,4, Jonatan R Ruiz2. 1. EFFECTS-262 Research Group, Department of Physiology, School of Medicine, University of Granada, Spain. 2. PROmoting FITness and Health through Physical Activity Research Group, Sport and Health University Research Institute, Department of Physical and Sports Education, School of Sports Science, University of Granada, Spain. 3. GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain. 4. CIBER of Frailty and Healthy Aging, Madrid, Spain.
Abstract
CONTEXT: We examined whether obese individuals have a reduced maximal fat oxidation (MFO) and the intensity that elicit MFO (Fatmax) compared with normal weight and overweight persons, taking into account their level of cardiorespiratory fitness. METHODS: The study subjects were 138 sedentary adults (87 women) aged 30.1 ± 13.6 years. Based on their body mass index, subjects were categorized as being of normal weight (n = 66), overweight (n = 48), or obese (n = 24). MFO and Fatmax were determined for all subjects by indirect calorimetry, using a walking graded exercise test. MFO was expressed in absolute terms (g/min) and relative to whole-body lean mass (mg/kgleanmass/min). Cardiorespiratory fitness was assessed via a maximal treadmill test. RESULTS: No differences in absolute MFO and Fatmax values were seen between the obese, normal weight, and overweight subjects (all P > 0.2), although after adjusting for cardiorespiratory fitness, the obese subjects returned significantly higher values than did their normal weight and overweight counterparts (all P < 0.03). However, when expressed with respect to lean mass, the MFO of the normal weight subjects was significantly greater than that of the overweight and obese subjects, independent of age, sex, or cardiorespiratory fitness. CONCLUSIONS: Obese individuals have higher absolute MFO values when cardiorespiratory fitness is taken into account, but when expressed with respect to lean mass, normal weight individuals show a greater capacity to oxidize fat during exercise per unit of metabolically active tissue independent of age, sex, or cardiorespiratory fitness. These findings suggest that obese individuals may suffer from metabolic inflexibility during exercise.
CONTEXT: We examined whether obese individuals have a reduced maximal fat oxidation (MFO) and the intensity that elicit MFO (Fatmax) compared with normal weight and overweight persons, taking into account their level of cardiorespiratory fitness. METHODS: The study subjects were 138 sedentary adults (87 women) aged 30.1 ± 13.6 years. Based on their body mass index, subjects were categorized as being of normal weight (n = 66), overweight (n = 48), or obese (n = 24). MFO and Fatmax were determined for all subjects by indirect calorimetry, using a walking graded exercise test. MFO was expressed in absolute terms (g/min) and relative to whole-body lean mass (mg/kgleanmass/min). Cardiorespiratory fitness was assessed via a maximal treadmill test. RESULTS: No differences in absolute MFO and Fatmax values were seen between the obese, normal weight, and overweight subjects (all P > 0.2), although after adjusting for cardiorespiratory fitness, the obese subjects returned significantly higher values than did their normal weight and overweight counterparts (all P < 0.03). However, when expressed with respect to lean mass, the MFO of the normal weight subjects was significantly greater than that of the overweight and obese subjects, independent of age, sex, or cardiorespiratory fitness. CONCLUSIONS:Obese individuals have higher absolute MFO values when cardiorespiratory fitness is taken into account, but when expressed with respect to lean mass, normal weight individuals show a greater capacity to oxidize fat during exercise per unit of metabolically active tissue independent of age, sex, or cardiorespiratory fitness. These findings suggest that obese individuals may suffer from metabolic inflexibility during exercise.
Authors: Isaac A Chávez-Guevara; Rosa P Hernández-Torres; Everardo González-Rodríguez; Arnulfo Ramos-Jiménez; Francisco J Amaro-Gahete Journal: Eur J Appl Physiol Date: 2022-04-01 Impact factor: 3.346
Authors: Francisco J Osuna-Prieto; Francisco M Acosta; Unai A Perez de Arrilucea Le Floc'h; Blanca Riquelme-Gallego; Elisa Merchan-Ramirez; Huiwen Xu; Juan Carlos De La Cruz-Márquez; Francisco J Amaro-Gahete; Jose A Llamas-Elvira; Eva M Triviño-Ibáñez; Antonio Segura-Carretero; Jonatan R Ruiz Journal: J Int Soc Sports Nutr Date: 2022-07-19 Impact factor: 4.948
Authors: Isaac A Chávez-Guevara; René Urquidez-Romero; Jorge A Pérez-León; Everardo González-Rodríguez; Verónica Moreno-Brito; Arnulfo Ramos-Jiménez Journal: Int J Environ Res Public Health Date: 2020-10-28 Impact factor: 3.390