In:
The Journal of Clinical Endocrinology & Metabolism, The Endocrine Society, Vol. 104, No. 12 ( 2019-12-01), p. 5780-5790
Abstract:
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.
Type of Medium:
Online Resource
ISSN:
0021-972X
,
1945-7197
DOI:
10.1210/jc.2019-01225
Language:
English
Publisher:
The Endocrine Society
Publication Date:
2019
detail.hit.zdb_id:
2026217-6
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