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Cardiovascular factors explain genetic background differences in VO 2 max
Author(s) -
Roy Jane L.P.,
Hunter Gary R.,
Fernandez Jose R.,
McCarthy John P.,
LarsonMeyer D. Enette,
Blaudeau Tamilane E.,
Newcomer Bradley R.
Publication year - 2006
Publication title -
american journal of human biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.559
H-Index - 81
eISSN - 1520-6300
pISSN - 1042-0533
DOI - 10.1002/ajhb.20509
Subject(s) - treadmill , vo2 max , medicine , oxidative phosphorylation , zoology , endocrinology , heart rate , chemistry , blood pressure , biology , biochemistry
The purpose of this study was to further explore factors that may be related to ethnic differences in the maximum rate at which an individual can consume oxygen (VO 2 max) between 20 African American (AA) and 30 European American (EA) sedentary women who were matched for body weight (kg) and fat‐free mass (FFM). VO 2 max (l/min) was determined during a graded treadmill exercise test. Submaximal steady‐state heart rate and submaximal VO 2 were determined at a treadmill speed of 1.3 m/sec and a 2.5% grade. Hemoglobin (Hb) was determined by the cyanide method, muscle oxidative capacity by 31 P magnetic resonance spectroscopy (ADP time constant), and FFM (kg) by dual‐energy x‐ray absorptiometry. Genetic classification was self‐reported, and in a subset of the sample (N = 32), the determinants of ethnicity were measured by African genetic admixture. AA women had significantly reduced VO 2 max, Hb levels, and muscle oxidative capacity (longer ADP time constants, P ≤ 0.05) than EA women. Submaximal oxygen pulse (O 2 Psubmax), ADP time constant, Hb, and ethnic background were all significantly related to VO 2 max (ml/kg/min and ml/kg FFM/min, all P ≤ 0.01). By multiple regression modeling, Hb, O 2 Psubmax, muscle oxidative capacity, and ethnicity were found to explain 61% and 57% of the variance of VO 2 max in ml/kg/min and ml/kg FFM/min, respectively. Muscle oxidative capacity and O 2 Psubmax were both significantly and independently related to VO 2 max in all three models ( P ≤ 0.05), whereas Hb and ethnicity were not. These results suggest that mitochondrial muscle oxidative capacity and oxygen delivery capabilities, as determined by O 2 Psubmax, account for most if not all of the ethnic differences in VO 2 max. Am. J. Hum. Biol. 18:454–460, 2006. © 2006 Wiley‐Liss, Inc.