Is Elevation Training Mask a Strategy to Increase Lactate Clearance Through Respiratory Muscle Loading?

Request for Clarification: Developing devices to maximize training-induced adaptations has become a fruitful area. The interesting study of Jagim et al. (4) investigated the acute effects of the Elevation Training Mask 2.0 (ETM) on resistance exercise and sprint performance. Results of the ETM usage include intolerance by 12% of subjects, no differences in number of repetitions or total volume load performed, and reduction in peak, but not average velocity or total work accomplished. Intriguingly, they reported lower blood lactate concentrations ([Lac]) after exercises in the ETM condition, which they justified by lower peak of exercise velocity. The authors attributed these results to the lower recruitment of fast-twitch muscle fibers, which possess great potential for lactate production because of their higher reliance on anaerobic glycolysis. Although the hypothesis of reduction of fast-twitch muscle fiber recruitment is supported by the results found, it does not take in account that [Lac] represents the balance between lactate release and uptake by the exercised muscles and other tissues (6). We propose that the ETM improves clearance of [Lac] through increased respiratory muscle workload, thereby increasing transport and its use as fuel. The impact of breathe loading on whole-body [Lac] clearance is known (1–3,5). It has been suggested that, by increasing the effort of breathing, respiratory muscles may increase the [Lac] clearance because of their large content of monocarboxylate transporter and oxidative capacity. This is in agreement with previous findings that show that breathing against airflow resistance not only improves [Lac] clearance, but also subsequent exercise performance (2). Performance was not improved with the ETM usage in the study by Jagim et al (4). Thus, it could be argued that the ETM did not work as respiratory muscle loading device. However, differences in study designs have to be recognized because, in the study by Chiappa et al. (2), airflow resistance was imposed during recovery producing the benefits of [Lac] clearance without side-effects such as loss of focus during the task (4). In this sense, it could be interesting to analyze the contribution of exercise velocity changes in the reduction of [Lac], to estimate how much of this reduction may be due to other factors such as the lactate clearance by respiratory muscles. Finally, we acknowledge the elegant study of Jagim et al. (4), which certainly represents a necessary advance in this area of knowledge. We hope our thoughts can expand discussions about the ETM and point out possible new applications.

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