title: Relative contribution of organs other than brain to resting energy expenditure is consistent among male power athletes.
abstract: We have previously shown that resting energy expenditure (REE) adjusted by fat-free mass (FFM) in male college athletes remains consistent regardless of FFM. The FFM comprises internal organs with high metabolic activity, such as liver and brain, which account for 60 to 80% of REE in adults. The purpose of the present study is to examine the contribution of internal organs to the REE of the FFM fraction among male power athletes. The study included 37 American male college football players. REE was measured by indirect calorimetry and body composition was measured by dual energy X-ray absorptiometry (DXA). Mass of brain, liver, and kidneys was measured by MRI and mass of heart was estimated by echocardiography. Normal levels of thyroid hormone (triiodothyronine: T3) were confirmed in all subjects prior to the analysis. Multiple regression analysis was used to assess the influence of FFM, fat mass (FM), T3, and mass of organs on variance of REE. Average body weight and FFM were 81.2±11.3 kg and 67.7±7.4 kg, respectively. The relative contributions of liver, kidneys, and heart to REE were consistent regardless of FFM, while the REE of brain was negatively correlated with FFM (r=-0.672, p<0.001). Only FFM and T3 were found to be independent factors influencing REE. These results suggest that a steady contribution of internal organs other than the brain is the major reason for the consistency of the REE/FFM ratio in male power athletes.
authors.affiliation: Graduate School of Sport Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Oshima
authors.forename: Sakiho
authors.initials: S
authors.lastname: Miyauchi
authors.forename: Meiko
authors.initials: M
authors.lastname: Asaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawano
authors.forename: Motoko
authors.initials: M
authors.lastname: Taguchi
authors.forename: Suguru
authors.initials: S
authors.lastname: Torii
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Higuchi
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D056352:Athletes; D001481:Basal Metabolism; D001823:Body Composition; D001825:Body Fluid Compartments / Q000378:metabolism*; D001835:Body Weight; D001921:Brain / Q000378:metabolism*; D002153:Calorimetry, Indirect; D005538:Football / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size; D012146:Rest / Q000502:physiology; D014284:Triiodothyronine / Q000097:blood; D014481:United States; D055815:Young Adult
chemical_list: D014284:Triiodothyronine