Fat oxidation at rest predicts peak fat oxidation during exercise and metabolic phenotype in overweight men

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M Rosenkilde, P Nordby, L B Nielsen, B M Stallknecht, J W Helge

OBJECTIVE: To elucidate if fat oxidation at rest predicts peak fat oxidation during exercise and/or metabolic phenotype in moderately overweight, sedentary men. DESIGN: Cross-sectional study.Subjects:We measured respiratory exchange ratio (RER) at rest in 44 moderately overweight, normotensive and normoglycemic men and selected 8 subjects with a low RER (L-RER, body mass index (BMI): 27.9+/-0.9 kg m(-2), RER: 0.76+/-0.02) and 8 with a high RER (H-RER; BMI 28.1+/-1.1 kg m(-2), RER: 0.89+/-0.02). After an overnight fast, a venous blood sample was obtained and a graded exercise test was performed. Fat oxidation during exercise was quantified using indirect calorimetry. RESULTS: Peak fat oxidation during exercise was higher in L-RER than in H-RER (0.333+/-0.096 vs 0.169+/-0.028 g min(-1); P<0.01) and occurred at a higher relative intensity (36.2+/-6.6 vs 28.2+/-3.1% VO(2max), P<0.05). Using the International Diabetes Federation criteria, we found that there was a lower accumulation of metabolic risk factors in L-RER than in H-RER (1.6 vs 3.5, P=0.028), and no subjects in L-RER and four of eight subjects in H-RER had the metabolic syndrome. Resting RER was positively correlated with plasma triglycerides (P<0.01) and negatively with plasma free fatty acids (P<0.05), and peak fat oxidation during exercise was positively correlated with plasma free fatty acid concentration at rest (P<0.05). CONCLUSION: A low RER at rest predicts a high peak fat oxidation during exercise and a healthy metabolic phenotype in moderately overweight, sedentary men.
OriginalsprogEngelsk
TidsskriftInternational Journal of Obesity
Vol/bind34
Udgave nummer5
Sider (fra-til)871-7
Antal sider6
ISSN0307-0565
DOI
StatusUdgivet - 2010

ID: 20095749