Response to the letter to the editor regarding the article “A 4-week endurance training program improves tolerance to mental exertion in untrained individuals”

We would like to thank you for the opportunity to respond to the points raised in de Lima-Junior and colleagues' letter and to clarify aspects of our discussion in relation to these points. We would also like to thank de Lima-Junior and colleagues for their interest in our paper and for taking the time to provide their commentary. In their letter to the editor, the authors proposed an alternative conclusion based on their interpretation of our results.1 Their attention was focused on the effect of the physical intervention on mental fatigue tolerance. We agree that peripheral adaptations will be responsible for much of the improvements in fitness and performance-related variables, including VO2peak, time trial performance and even the power relative to RPE. This is a common outcome of endurance training interventions,6 but our paper was not focused on this aspect. However, our point regarding central adaptations being evident is based on the interplay between the physical training, and mental exertion vs control time-trials. We considered how much the time-trial performance “suffered” following the mental exertion exposure. Before the 6-week intervention, both groups performed worse following the mental exertion trial compared to the control trial, such that the placebo group's performance deteriorated by, on average, 2.93%. The training group's performance, before training, was on average 3.68% worse following the mental exertion trial compared to the control condition. We consider this a typical effect of mental fatigue on time trial performance(7).