Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men
Introduction: In men, whole body peak fat oxidation (PFO) determined by a graded exercise test is closely tied to plasma free fatty acid (FFA) availability. Men and women exhibit divergent metabolic responses to fasting and exercise, and it remains unknown how the combined fasting and exercise affec...
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| Format: | Article |
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Frontiers Media S.A.
2021-08-01
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| Series: | Frontiers in Physiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fphys.2021.696261/full |
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| author | Jacob Frandsen Axel Illeris Poggi Christian Ritz Steen Larsen Steen Larsen Flemming Dela Flemming Dela Jørn W. Helge |
| author_facet | Jacob Frandsen Axel Illeris Poggi Christian Ritz Steen Larsen Steen Larsen Flemming Dela Flemming Dela Jørn W. Helge |
| author_sort | Jacob Frandsen |
| collection | DOAJ |
| description | Introduction: In men, whole body peak fat oxidation (PFO) determined by a graded exercise test is closely tied to plasma free fatty acid (FFA) availability. Men and women exhibit divergent metabolic responses to fasting and exercise, and it remains unknown how the combined fasting and exercise affect substrate utilization in women. We aimed to investigate this, hypothesizing that increased plasma FFA concentrations in women caused by fasting and repeated exercise will increase PFO during exercise. Then, that PFO would be higher in women compared with men (data from a previous study).Methods: On two separate days, 11 young endurance-trained women were investigated, either after an overnight fast (Fast) or 3.5 h after a standardized meal (Fed). On each day, a validated graded exercise protocol (GXT), used to establish PFO by indirect calorimetry, was performed four times separated by 3.5 h of bed rest both in the fasted (Fast) or fed (Fed) state.Results: Peak fat oxidation increased in the fasted state from 11 ± 3 (after an overnight fast, Fast 1) to 16 ± 3 (mean ± SD) mg/min/kg lean body mass (LBM) (after ~22 h fast, Fast 4), and this was highly associated with plasma FFA concentrations, which increased from 404 ± 203 (Fast 1) to 865 ± 210 μmol/L (Fast 4). No increase in PFO was found during the fed condition with repeated exercise. Compared with trained men from a former identical study, we found no sex differences in relative PFO (mg/min/kg LBM) between men and women, in spite of significant differences in plasma FFA concentrations during exercise after fasting.Conclusion: Peak fat oxidation increased with fasting and repeated exercise in trained women, but the relative PFO was similar in young trained men and women, despite major differences in plasma lipid concentrations during graded exercise. |
| first_indexed | 2024-12-13T22:12:25Z |
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| institution | Directory Open Access Journal |
| issn | 1664-042X |
| language | English |
| last_indexed | 2024-12-13T22:12:25Z |
| publishDate | 2021-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Physiology |
| spelling | doaj.art-af7bb957c0414f8ea239614192fc751b2022-12-21T23:29:41ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2021-08-011210.3389/fphys.2021.696261696261Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to MenJacob Frandsen0Axel Illeris Poggi1Christian Ritz2Steen Larsen3Steen Larsen4Flemming Dela5Flemming Dela6Jørn W. Helge7Xlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, University of Copenhagen, Copenhagen, DenmarkXlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, University of Copenhagen, Copenhagen, DenmarkDepartment of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, DenmarkXlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, University of Copenhagen, Copenhagen, DenmarkClinical Research Centre, Medical University of Białystok, Białystok, PolandXlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, University of Copenhagen, Copenhagen, DenmarkDepartment of Geriatrics, Bispebjerg University Hospital, Copenhagen, DenmarkXlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, University of Copenhagen, Copenhagen, DenmarkIntroduction: In men, whole body peak fat oxidation (PFO) determined by a graded exercise test is closely tied to plasma free fatty acid (FFA) availability. Men and women exhibit divergent metabolic responses to fasting and exercise, and it remains unknown how the combined fasting and exercise affect substrate utilization in women. We aimed to investigate this, hypothesizing that increased plasma FFA concentrations in women caused by fasting and repeated exercise will increase PFO during exercise. Then, that PFO would be higher in women compared with men (data from a previous study).Methods: On two separate days, 11 young endurance-trained women were investigated, either after an overnight fast (Fast) or 3.5 h after a standardized meal (Fed). On each day, a validated graded exercise protocol (GXT), used to establish PFO by indirect calorimetry, was performed four times separated by 3.5 h of bed rest both in the fasted (Fast) or fed (Fed) state.Results: Peak fat oxidation increased in the fasted state from 11 ± 3 (after an overnight fast, Fast 1) to 16 ± 3 (mean ± SD) mg/min/kg lean body mass (LBM) (after ~22 h fast, Fast 4), and this was highly associated with plasma FFA concentrations, which increased from 404 ± 203 (Fast 1) to 865 ± 210 μmol/L (Fast 4). No increase in PFO was found during the fed condition with repeated exercise. Compared with trained men from a former identical study, we found no sex differences in relative PFO (mg/min/kg LBM) between men and women, in spite of significant differences in plasma FFA concentrations during exercise after fasting.Conclusion: Peak fat oxidation increased with fasting and repeated exercise in trained women, but the relative PFO was similar in young trained men and women, despite major differences in plasma lipid concentrations during graded exercise.https://www.frontiersin.org/articles/10.3389/fphys.2021.696261/fullfat oxidation ratefastrepeated exerciseFATmaxsubstrate availability |
| spellingShingle | Jacob Frandsen Axel Illeris Poggi Christian Ritz Steen Larsen Steen Larsen Flemming Dela Flemming Dela Jørn W. Helge Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men Frontiers in Physiology fat oxidation rate fast repeated exercise FATmax substrate availability |
| title | Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men |
| title_full | Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men |
| title_fullStr | Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men |
| title_full_unstemmed | Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men |
| title_short | Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men |
| title_sort | peak fat oxidation rate is closely associated with plasma free fatty acid concentrations in women similar to men |
| topic | fat oxidation rate fast repeated exercise FATmax substrate availability |
| url | https://www.frontiersin.org/articles/10.3389/fphys.2021.696261/full |
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