Abstract
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% VO2max, 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.
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% VO2max, 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.
| Original language | English |
|---|---|
| Journal | International Journal of Obesity |
| Volume | 34 |
| Issue number | 5 |
| Pages (from-to) | 871-877 |
| ISSN | 0307-0565 |
| DOIs | |
| Publication status | Published - 2010 |
| Externally published | Yes |
Keywords
- Rest
- Metabolic syndrome
- Phenotypes
- Exercise
- Lipid metabolism
