Highlighting the Role of Mental Fatigue as a Health Risk Factor: A Narrative Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I appreciate the authors’ efforts in preparing this narrative review on mental fatigue as a potential health risk factor. The topic is timely and the manuscript has clear relevance for exercise science and public health, especially in its emphasis on vulnerable populations and fatigability. That said, several aspects should be improved to strengthen readability, structure, and scientific depth before the paper can be considered for acceptance.

First, the manuscript would benefit from clearer and higher-quality visual materials. Given that this is a review paper proposing pathways and mechanisms, I encourage the authors to include one or more well-designed, high-resolution figures (e.g., a conceptual diagram or flowchart) that can help readers quickly grasp the key constructs, proposed pathways, and the overall model. Improving figure aesthetics and clarity would substantially enhance accessibility for a broad readership.

Second, there appear to be formatting and organizational issues, particularly in the Introduction. The current section contains too many subheadings, and the relationships among these subsections are not sufficiently clear. I suggest revising the heading structure to better reflect a logical hierarchy (e.g., moving from definitions → scope of the problem → vulnerable populations → proposed health impacts). A streamlined outline would make the narrative easier to follow and improve coherence.

Third, the manuscript should provide more mechanistic explanations where possible. For example, when discussing countermeasures such as caffeine, it would strengthen the review to briefly summarize plausible biological pathways (e.g., neurochemical or molecular mechanisms) through which caffeine might influence mental fatigue and related outcomes. In this context, the authors may consider consulting and citing relevant mechanistic literature (e.g., DOI: 10.3390/nu16101421) to support these statements and improve scientific rigor.

Overall, I view the manuscript as promising, but I recommend revision to address (1) figure quality and conceptual visualization, (2) section structure and formatting clarity, and (3) deeper mechanistic support for key claims and interventions.

Comments on the Quality of English Language

ok

Author Response

Reviewer 1

 

I appreciate the authors’ efforts in preparing this narrative review on mental fatigue as a potential health risk factor. The topic is timely and the manuscript has clear relevance for exercise science and public health, especially in its emphasis on vulnerable populations and fatigability. That said, several aspects should be improved to strengthen readability, structure, and scientific depth before the paper can be considered for acceptance.

 

Response: We thank the reviewer for the positive evaluation of the topic and for recognizing the relevance of the manuscript for exercise science and public health.

 

First, the manuscript would benefit from clearer and higher-quality visual materials. Given that this is a review paper proposing pathways and mechanisms, I encourage the authors to include one or more well-designed, high-resolution figures (e.g., a conceptual diagram or flowchart) that can help readers quickly grasp the key constructs, proposed pathways, and the overall model. Improving figure aesthetics and clarity would substantially enhance accessibility for a broad readership.

 

Response: We fully agree with this comment. To improve conceptual clarity and accessibility, we have revised the description and role of the conceptual model and developed a more pathway-oriented and visually intuitive representation of mental fatigue as a health risk factor. The revised Figure 1 now emphasizes multiple pathways linking inputs, mediating mechanisms, and health-related outputs, with a specific focus on vulnerable populations. The figure description and its integration into the text have been strengthened in the Introduction and Conceptual Model sections.

 

Second, there appear to be formatting and organizational issues, particularly in the Introduction. The current section contains too many subheadings, and the relationships among these subsections are not sufficiently clear. I suggest revising the heading structure to better reflect a logical hierarchy (e.g., moving from definitions → scope of the problem → vulnerable populations → proposed health impacts). A streamlined outline would make the narrative easier to follow and improve coherence.

 

Response: We appreciate this observation. The Introduction has been reorganized to improve readability and logical flow. Specifically, the section now progresses from (i) definition and relevance of mental fatigue, to (ii) its public health significance, (iii) vulnerable populations, and (iv) the objectives and conceptual framework of the review. Subheadings have been streamlined and the hierarchy clarified to enhance narrative coherence.

 

Third, the manuscript should provide more mechanistic explanations where possible. For example, when discussing countermeasures such as caffeine, it would strengthen the review to briefly summarize plausible biological pathways (e.g., neurochemical or molecular mechanisms) through which caffeine might influence mental fatigue and related outcomes. In this context, the authors may consider consulting and citing relevant mechanistic literature (e.g., DOI: 10.3390/nu16101421) to support these statements and improve scientific rigor.

Overall, I view the manuscript as promising, but I recommend revision to address (1) figure quality and conceptual visualization, (2) section structure and formatting clarity, and (3) deeper mechanistic support for key claims and interventions.

Response: We agree that mechanistic explanations strengthen the scientific rigor of a narrative review. Accordingly, we have expanded the mechanistic discussion of key mitigation strategies, particularly caffeine. The revised manuscript now includes a brief description of plausible neurobiological mechanisms (e.g., adenosine receptor antagonism, dopaminergic modulation, and effects on perceived effort) underlying caffeine’s effects on mental fatigue and performance. Relevant mechanistic literature has been incorporated to support these claims.

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

This is an excellent topic for a narrative review, addressing a crucial and often overlooked aspect of mental fatigue.

For better understanding for readers, I suggest to reorganize the content

1. Introduction (with subsections, if appropriate)
2. Conceptual Model for Mental Fatigue as a Health Risk Factor (with subsections if appropriate)
3. Strategies for Mental Fatigue Mitigation
4. Future research
5. Conclusions

Also, because a narrative review isn't just a summary; you need to do a critical synthesis.

You should present (1) Why the factors of mental fatigue are important? (2) How the mechanisms lead to health risks? (3) What are the implication? (4) Are there conflict in findings? Are there limitation of existing research?

Also, in the abstract you mention about “vulnerable population”. Please ensure this topic is related with content. Identify the vulnerable groups and be more specific in target group dscription. You mentioned in the manuscript “population”.

By addressing these points, you can transform your current manuscript in a impactful narrative review. Good luck!

Comments on the Quality of English Language

Ensure consistent use of terms like "mental fatigue," "fatigability," "health risk factor," etc.

A meticulous review by a native English speaker is recommended.

Author Response

Reviewer 2

Dear Authors,

This is an excellent topic for a narrative review, addressing a crucial and often overlooked aspect of mental fatigue.

Response: We thank the reviewer for encouraging assessment and constructive suggestions.

For better understanding for readers, I suggest to reorganize the content

1. Introduction (with subsections, if appropriate)
2. Conceptual Model for Mental Fatigue as a Health Risk Factor (with subsections if appropriate)
3. Strategies for Mental Fatigue Mitigation
4. Future research
5. Conclusions

 

Response: We have fully adopted the proposed structure. The manuscript is now organized as follows: 1)Introduction; 2) Conceptual Model for Mental Fatigue as a Health Risk Factor; 3) Strategies for Mental Fatigue Mitigation; 4) Future Research; 5) Conclusions. This reorganization has improved clarity and better reflects the narrative logic of the review.

Also, because a narrative review isn't just a summary; you need to do a critical synthesis.

You should present (1) Why the factors of mental fatigue are important? (2) How the mechanisms lead to health risks? (3) What are the implication? (4) Are there conflict in findings? Are there limitation of existing research?

Response: We fully agree. The revised manuscript places greater emphasis on critical synthesis by explicitly addressing:

• why mental fatigue–related factors are important,
• how subjective, behavioral, and physiological mechanisms translate into health risks,
• the broader implications for public health and prevention, and
• limitations and gaps in the existing literature.

These elements are now more clearly articulated throughout the Conceptual Model, Outputs, and Future Research sections.

Also, in the abstract you mention about “vulnerable population”. Please ensure this topic is related with content. Identify the vulnerable groups and be more specific in target group dscription. You mentioned in the manuscript “population”.

Response: “Thank you for highlighting this point. We have clarified and consistently defined vulnerable populations throughout the manuscript, including older adults, individuals with chronic diseases (e.g., cancer, cardiovascular disease), and populations with reduced cognitive or physical reserve. The term “population” is now used more precisely, and links between vulnerability, fatigability, and health risk are explicitly discussed.”

By addressing these points, you can transform your current manuscript in a impactful narrative review. Good luck!

Response: Appreciated

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This is a very interesting article that, while not identified as a literature review, reflects the opinion and knowledge of its authors based on the literature. The topic may be interesting, especially when associated with the exploration of overtraining and its prevention in athletes which is not refered here...unfortunatly...

The objective of this article/publication should be more clear to the reader.

In another context of the article, the authors refer to the "older" population where cognitive fatigability can indeed be a public health problem. They advocate BET (Brain Endurance  Training) but forget to mention Dual Task Training, which has been part of interventions with older populations for quite some time as a way to address cognitive changes. Where is the difference between these two methodologies??? (BET and Dual Task Training). I consider it important in this context to integrate this approach, since they refer to it as a gap yet to be explored in future research. However, there is already quite a bit (although not yet sufficient) on dual-task training in different clinical conditions.

Some minor corrections:

In Figure 1 - the figure titles always appear below them. There should be a caption, for example, for the expression "RPE," which appears here for the first time in the text, even though its meaning is explained in full later (line 90). Shouldn't it be RPE = Rates of Perceived Exertion?

On line 113 - Where it says "health problems," shouldn't it be "health problems"?

Author Response

Reviewer 3

 

This is a very interesting article that, while not identified as a literature review, reflects the opinion and knowledge of its authors based on the literature. The topic may be interesting, especially when associated with the exploration of overtraining and its prevention in athletes which is not refered here...unfortunatly...

 

Response: We thank the reviewer for the thoughtful and detailed feedback. We have extended the information on overtraining in athletes as well.

 

The objective of this article/publication should be more clear to the reader. In another context of the article, the authors refer to the "older" population where cognitive fatigability can indeed be a public health problem.

 

Response: We agree and have clarified the objective of the manuscript in the Introduction. The revised text now explicitly states that the aim is to conceptualize mental fatigue as a population-specific health risk factor, synthesize mechanistic evidence, identify vulnerable groups, and discuss implications for prevention and intervention.

 

They advocate BET (Brain Endurance  Training) but forget to mention Dual Task Training, which has been part of interventions with older populations for quite some time as a way to address cognitive changes. Where is the difference between these two methodologies??? (BET and Dual Task Training). I consider it important in this context to integrate this approach, since they refer to it as a gap yet to be explored in future research. However, there is already quite a bit (although not yet sufficient) on dual-task training in different clinical conditions.

 

Response: We appreciate this important observation. We have now integrated Dual-Task Training into the Strategies for Mental Fatigue Mitigation section. The revised manuscript explicitly contrasts BET and traditional dual-task approaches, highlighting their conceptual overlap while clarifying key differences—namely, BET’s systematic induction of mental fatigue and its focus on effort perception and fatigue tolerance. We also acknowledge existing evidence on dual-task training in older and clinical populations and discuss how integrating both approaches may inform future research.

 

Some minor corrections:

 

In Figure 1 - the figure titles always appear below them. There should be a caption, for example, for the expression "RPE," which appears here for the first time in the text, even though its meaning is explained in full later (line 90). Shouldn't it be RPE = Rates of Perceived Exertion?

 

Response: This typographical issue has been corrected in the revised manuscript.

 

On line 113 - Where it says "health problems," shouldn't it be "health problems"?

 

Response: Minor wording correction (‘health problems’).¡

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you to the author for explaining all my questions; I support the publication of this article.

Comments on the Quality of English Language

ok