Response: Commentary on the effects of hypoxia on energy substrate use during exercise

Abstract

Background

A recent commentary has been published on our meta-analysis, which investigated substrate oxidation during exercise matched for relative intensities in hypoxia compared with normoxia. Within this commentary, the authors proposed that exercise matched for absolute intensities in hypoxia compared with normoxia, should have been included within the analysis, as this model provides a more suitable experimental design when considering nutritional interventions in hypoxia.

Main body

Within this response, we provide a rationale for the use of exercise matched for relative intensities in hypoxia compared with normoxia. Specifically, we argue that this model provides a physiological stimulus replicable of real world situations, by reducing the absolute workload undertaken in hypoxia. Further, the use of exercise matched for relative intensities isolates the metabolic response to hypoxia, rather than the increased relative exercise intensity experienced in hypoxia when utilising exercise matched for absolute intensities. In addition, we also report previously unpublished data analysed at the time of the original meta-analysis, assessing substrate oxidation during exercise matched for absolute intensities in hypoxia compared with normoxia.

Conclusion

An increased reliance on carbohydrate oxidation was observed during exercise matched for absolute intensities in hypoxia compared with normoxia. These data now provide a comparable dataset for the use of researchers and practitioners alike in the design of nutritional interventions for relevant populations.

Keywords:

• Altitude
• Carbohydrate
• Fat
• Oxidation
• Relative
• Absolute
• RER

Acknowledgements

Not applicable.

Authors’ contributions

AG, JOH, KD and RK conceived and planned the study. AG, JM, OS and KD conducted the search and were involved in the review and extraction of all data. AG, JM and KD performed the analysis on the extracted data. All authors discussed the interpretation of results. AG wrote the manuscript. All authors provided critical feedback and helped shape the manuscript. All authors read and approved the final manuscript.

Funding

Not applicable.

Availability of data and materials

The data analysed and generated in this study are included in this published article and the associated additional files.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Supplementary information

Supplementary information accompanies this paper at https://doi.org/10.1186/s12970-019-0330-7.

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