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. 2019 Nov 25;14(11):e0225803.
doi: 10.1371/journal.pone.0225803. eCollection 2019.

Aerobic Exercise Increases Post-Exercise Exogenous Protein Oxidation in Healthy Young Males

Free PMC article

Aerobic Exercise Increases Post-Exercise Exogenous Protein Oxidation in Healthy Young Males

Gerlof A R Reckman et al. PLoS One. .
Free PMC article


The capacity to utilize ingested protein for optimal support of protein synthesis and lean body mass is described within the paradigm of anabolic competence. Protein synthesis can be stimulated by physical exercise, however, it is not known if physical exercise affects post-exercise protein oxidation. Characterization of the driving forces behind protein oxidation, such as exercise, can contribute to improved understanding of whole body protein metabolism. The purpose of this study is to determine the effect of two levels of aerobic exercise intensity on immediate post-exercise exogenous protein oxidation. Sixteen healthy males with a mean (SD) age of 24 (4) years participated. The subjects' VO2-max was estimated with the Åstrand cycling test. Habitual dietary intake was assessed with a three-day food diary. Exogenous protein oxidation was measured by isotope ratio mass spectrometry. These measurements were initiated after the ingestion of a 30 g 13C-milk protein test drink that was followed by 330 minutes breath sample collection. On three different days with at least one week in between, exogenous protein oxidation was measured: 1) during rest, 2) after 15 minutes of aerobic exercise at 30% of VO2-max (moderate intensity), and 3) after 15 minutes of aerobic exercise at 60% of VO2-max (vigorous intensity). After vigorous intensity aerobic exercise, 31.8%±8.0 of the 30 g 13C-milk protein was oxidized compared to 26.2%±7.1 during resting condition (p = 0.012), and 25.4%±7.6 after moderate intensity aerobic exercise compared to resting (p = 0.711). In conclusion, exogenous protein oxidation is increased after vigorous intensity aerobic exercise which could be the result of an increased protein turnover rate.

Conflict of interest statement

I have read the journal's policy and the authors of this manuscript have the following competing interests: The naturally enriched 13C-milk protein has been made available as an in kind contribution by Hanze Nutrition B.V., which is owned by co-author prof. dr. R.J. Vonk. This does not alter our adherence to PLOS ONE policies on sharing data and materials.


Fig 1
Fig 1. Exogenous protein oxidation kinetics during resting (black), after exercise at 30% VO2-max (red), and after exercise at 60% VO2-max (blue)(n = 16).
Fig 2
Fig 2. Total exogenous protein oxidation over 330 minutes as measured by the area under the concentration curve per subject at rest and after two levels of exercise (15 minutes cycling at 30% and 60% of subject’s VO2-max).
The mean is represented by the black line.

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Grant support

The author(s) received no specific funding for this work.