Diurnal Variation of Maximal Fat-Oxidation Rate in Trained Male Athletes

Research output: Contribution to journalJournal articlepeer-review

  • Francisco J. Amaro-Gahete
  • Lucas Jurado-Fasoli
  • Alejandro R. Trivino
  • Guillermo Sanchez-Delgado
  • Alejandro De-la-O
  • Helge, Jørn Wulff
  • Jonatan R. Ruiz
Purpose: To analyze the diurnal variation of maximal fat oxidation (MFO) and the intensity that elicits MFO (Fat(max)) in trained male athletes. Methods: A total of 12 endurance-trained male athletes age 24.7 (4.1) y participated in the study. The authors measured MFO, Fat(max), maximum oxygen uptake (VO(2)max), and VO2 percentage at ventilatory threshold 2 with a graded exercise protocol performed on 2 days separated by 1 wk. One test was performed in the morning and the other in the afternoon. The authors assessed the participants' chronotype using the HOME questionnaire. Results: MFO and Fat(max) were greater in the afternoon than in the morning (Delta = 13%, P < .001 and Delta = 6%, P = .001, respectively), whereas there were similar VO(2)max and ventilatory threshold 2 in the morning, than in the afternoon test (Delta = 0.2%, P = .158 and Delta = 7%, P = .650, respectively). There was a strong positive association between VO(2)max and MFO in both morning and afternoon assessments (R-2 = .783, P = .001 and R-2 = .663, P < .001, respectively). Similarly, there was a positive association between VO(2)max and Fat(max) in both morning and afternoon assessments (R-2 = .406, P = .024 and R-2 = .414, P = .026, respectively). Conclusion: MFO and Fat(max) may partially explain some of the observed diurnal variation in the performance of endurance sports.
Original languageEnglish
JournalInternational Journal of Sports Physiology and Performance
Issue number8
Pages (from-to)1140-1146
Publication statusPublished - 2019

    Research areas

  • Fat(max), VO(2)max, circadian rhythm, resistance, fuel oxidation

ID: 228530809