Effect of Physical Exercise on Sleep Quality in Elderly Adults: A Systematic Review with a Meta-Analysis of Controlled and Randomized Studies

Round 1

Reviewer 1 Report

Dear Authors; I think this is interesting meta analysis study on effect of physical exercise on sleep quality in elderly adults. However, its presentation needs some "serious work" to arrive to MDPI standards. Regards,

P.S.

 

[1] Writing:

  1-1 Format: Make sure to write full author affiliations in mdpi format with superscript numbers associated with the authors   1-2 Abbreviations: Right before reference section, add a list of abbreviation used in the manuscript for the readers easy access. Example: Abbreviations. Pittsburgh Sleep Quality Index (PSQI)   1-3 Missing citation: Add the related citation for  "RevMan 5 Software®" in line 123 in the reference section
  1-4 Inconsistency ONE: There is discrepancy in lines 142-147 and Figure 3 output.  Why did not the authors consider all 15 studies together ?  I think, the correct way to do this is to break down Figure 3 to two panels. In panel (a) show the Forest plot for all 15 studies combined, then in Panel(b) show them 11+4 like the current one.  This makes the presentation consistent and also elaborates the effect of neglecting insomnia status in the analysis to the reader.   1-5 Inconsistency TWO: Again, the authors mention 12 studies as in line 214. But, they have analyzed 11+4=15 in Figure 3. Need to be consistent throughout the paper.  15 ? 12 ?      1-6 Discussion: This is written very vague !  Break it down to three subsections: 4.1. This Work; 4.2. Limitations; 4.3. Future Work   1-7 Author Contributions: Missing info on authors !  "XX" , "YY" ?   1-8 References: Check them in MDPI format one more time !  Years for papers are in bold format.   [2] Statistical   2-1 Missing Statistical Power :  The manuscript needs to report its related statistical power for the performed meta analysis. Make sure to use the following sources in reporting them and cite them in the references section.   #1: Book:   https://0-link-springer-com.brum.beds.ac.uk/book/10.1007/978-1-4614-2278-5   #2: Shiny App:  https://jtiebel.shinyapps.io/MetaPowerCalculator/    

Author Response

Reviewer 1:

1-1 Format: Make sure to write full author affiliations in mdpi format with superscript numbers associated with the authors   

Answer: We corrected and improved the authors' presentation of their affiliations in MDPI format. 

1-2 Abbreviations: Right before reference section, add a list of abbreviation used in the manuscript for the readers easy access. Example: Abbreviations. Pittsburgh Sleep Quality Index (PSQI).

Answer: We have adhered to the suggestion for clarity of the manuscript. Thanks for the suggestions above

 1-3 Missing citation: Add the related citation for "RevMan 5 Software®" in line 123 in the reference section.

Answer: We agree with the comment, however, due to the importance of the citation, we have added the reference in the body of the text.

1-4 Inconsistency ONE: There is discrepancy in lines 142-147 and Figure 3 output.  Why did not the authors consider all 15 studies together?  I think, the correct way to do this is to break down Figure 3 to two panels. In panel (a) show the Forest plot for all 15 studies combined, then in Panel(b) show them 11+4 like the current one.  This makes the presentation consistent and also elaborates the effect of neglecting insomnia status in the analysis to the reader.

Answer: We apologize for not making it clear enough in the body of the text. We corrected this mistake. It is now explicit in the second paragraph of the "Article selection and bias analysis" section of the new document sent to the journal.

We actually selected 12 studies, but “divided 3 of these studies into two”. This made figure 3 presents 15 studies in its output. We did this because these 3 articles had two different intervention groups. The articles are Siu et al (Exe)/(Tai) 2021, Baker (SSSH)/(Walk) 2020, and Garcia et al (HIIT)/(MIIT) 2021.

At the bottom of Figure 3, we consider all 15 studies together, as we call it “Total”.

1-5 Inconsistency TWO: Again, the authors mention 12 studies as in line 214. But, they have analyzed 11+4=15 in Figure 3. Need to be consistent throughout the paper.  15 ? 12 ?      

Answer: As answered in the previous section, we actually selected 12 studies, but “divided 3 of these studies into two”. This made figure 3 present 15 studies in its output. We did this because these 3 articles had two different intervention groups. The articles are Siu et al (Exe)/(Tai) 2021, Baker (SSSH)/(Walk) 2020, and Garcia et al (HIIT)/(MIIT) 2021.

We apologize for not making it clear initially. 

1-6 Discussion: This is written very vague !  Break it down to three subsections: 4.1. This Work; 4.2. Limitations; 4.3. Future Work .

Answer: Thanks for the suggestion. We followed your recommendations which brought more clarity to the text.

 1-7 Author Contributions: Missing info on authors !  "XX" , "YY" ?   

Answer: We have completed this session. Thank you!

1-8 References: Check them in MDPI format one more time!  Years for papers are in bold format.   [2] Statistical   

Answer: We have checked the MDPI format and adjusted the references in the newly submitted manuscript. 

2-1 Missing Statistical Power :  The manuscript needs to report its related statistical power for the performed meta analysis. Make sure to use the following sources in reporting them and cite them in the references section.   #1: Book:   https://0-link-springer-com.brum.beds.ac.uk/book/10.1007/978-1-4614-2278-5   #2: Shiny App:  https://jtiebel.shinyapps.io/MetaPowerCalculator/

Answer: We would especially like to thank you for this comment. We were not familiar with the “Statistical power” approach. It was possible to increase the reliability of the article and to contribute to the knowledge of the team. We did not use many lines to explain the calculation method, we limited ourselves to just referencing the sources. We would like to emphasize that we used other ways of measuring the quality of evidence and risks of bias, such as Egger's test and the GRADE approach.

Reviewer 2 Report

Meta analisys is totally correct well done

 

Congratulations!

Meta analisys is totally correct well done

 

Congratulations!

Author Response

Review 2: 

Congratulations! Meta analysis is totally correct well done. Congratulations!

Answer: We appreciate the review work and the compliment.

Reviewer 3 Report

 congratulate the author(s) for the work done. It seems to me a relevant, current and necessary work. I believe, without a doubt, that it should be published and that it is relevant for the international scientific community. However, for its better visibility and readability, I make some minimal constructive recommendations, in the best academic spirit: 
The title is interesting, striking and complete, as well as representative of what is in the article. 
The summary is comprehensive, contains all the important sections and is well developed. However, digital learning environments should have the first letter capitalised, as it is part of an acronym. 
The keywords are very well chosen. However, as they are made up of conjunctions of two words, they can be detrimental to searches and their positioning in databases. If it were possible to add more keywords, I would recommend adding some more, which are simple and more general, so that they can be used more easily in searches. 
I think the introduction is too short for the importance of the topic. Perhaps it could be enriched with some commentary on an international report on the subject studied or similar recent academic work. 
In a journal of this prestige, the introduction or theoretical framework section should include current and recent references, from prestigious journals that have inspired this work because, in its current state, it does not present enough references and does not go into what is new, although the procedure, the sample and the interview are well explained.
The works cited are solid and prestigious but some are very old and there are few recent and international citations for a journal of this prestige. I recommend adding 5-6 super up-to-date references from top international journals, especially when you are offering an article that has so much peer-reviewed literature on a topic so close to home. These new references should only be from 2021 and 2022. 
The Results and Discussion section is brilliant, as the exposition and the argumentation are very well exposed and spun. 
It is necessary to develop a section on limitations and prospects, in a separate section at the end: why there is a problem (new, current, original) to investigate, why this methodology has been chosen and what limitations the chosen sample has, why there are conclusions that generate an original advance in knowledge, how this study can be replicated by the academic community. 
Scrupulously review the references, as they do not conform to the journal's standards and do not have the year of publication in bold type and where it corresponds. 

Author Response

Reviewer 3:

1. The summary is comprehensive, contains all the important sections and is well developed. However, digital learning environments should have the first letter capitalised, as it is part of an acronym.

Answer: We corrected this mistake. if another error still persists, please contact us.

2. The keywords are very well chosen. However, as they are made up of conjunctions of two words, they can be detrimental to searches and their positioning in databases. If it were possible to add more keywords, I would recommend adding some more, which are simple and more general, so that they can be used more easily in searches. 

Answer: Thanks for the suggestion. We followed your recommendations, and we added general keywords present on the MeSH terms.  

3. I think the introduction is too short for the importance of the topic. Perhaps it could be enriched with some commentary on an international report on the subject studied or similar recent academic work. 

Answer: Thank you for the commentary. We added a new paragraph (2nd paragraph of the new version manuscript) that contemplates a relevant subject.

4. The works cited are solid and prestigious but some are very old and there are few recent and international citations for a journal of this prestige. I recommend adding 5-6 super up-to-date references from top international journals, especially when you are offering an article that has so much peer-reviewed literature on a topic so close to home. These new references should only be from 2021 and 2022. 

Answer: We agree with your commentary. We have added 9 new updated references from top international journals. Two of them are in the introduction topic (2nd paragraph) and 7 others are in the discussion session (6th paragraph).

5. It is necessary to develop a section on limitations and prospects, in a separate section at the end: why there is a problem (new, current, original) to investigate, why this methodology has been chosen and what limitations the chosen sample has, why there are conclusions that generate an original advance in knowledge, how this study can be replicated by the academic community. 

Answer: We agree with your comment. Adding sections for limitations and prospects, made it article clearer.  

6. Scrupulously review the references, as they do not conform to the journal's standards and do not have the year of publication in bold type and where it corresponds. 

Answer: We have checked the MDPI format and adjusted the references in the newly submitted manuscript. Thank you for the warning.

We would like to thank you for your review. 

Reviewer 4 Report

Dear authors

Proposed mechanisms for why physical exercise improves sleep are vague (254-261). Among them is the production of hormones on circadian rhythms, which in humans are many (sleep, blood pressure, heart rate, heart rate variability, glucose metabolism, etc.). Review the effect of exercise on the Hypothalamic-Pituitary-Adrenal Axis and nervous system. On the other hand, the impact of physical exercise on melatonin production must mention what type of exercise and at what time it was performed. Realize a better review of the possible relationship between exercise, growth hormone, melatonin, and sleep, and if this relationship is short or long term.

Author Response

Reviewer 4:

1. Proposed mechanisms for why physical exercise improves sleep are vague (254-261). Among them is the production of hormones on circadian rhythms, which in humans are many (sleep, blood pressure, heart rate, heart rate variability, glucose metabolism, etc.). 

Answer: Thank you for the comment. We have made the proposed mechanism clearer. We apologize if we were not able to talk about the topic with the desired depth. Unfortunately, gaps in knowledge and the plethora of proposed mechanisms limit us to speak exhaustively about the mechanisms through which exercise impacts sleep. We have tried our best to cover as much of the mechanism as possible without losing focus for a systematic review in the 5th to 7th paragraph of the discussion section.

2. Review the effect of exercise on the Hypothalamic-Pituitary-Adrenal Axis and nervous system. 

Answer: Thank you for this commentary. The HPA axis represents an important mechanism on the subject. We have added a new topic in this section about it with new references (on the 7th paragraph of the discussion section)

3. The impact of physical exercise on melatonin production must mention what type of exercise and at what time it was performed.

Answer: We have improved this part (on the 5th paragraph of the discussion section). Thank you again.

4.  Realize a better review of the possible relationship between exercise, growth hormone, melatonin, and sleep, and if this relationship is short or long term.

Answer: This commentary was answered in the first and third parts of the author's reply.

We would like to thank you for your review. 

Reviewer 5 Report

Congratulations! this is a very great study. I have few commnets prior acceptance for publication in JAL.

Please, use the same objective from abstract in the end of introduction. In addition, the hypothesis of study is not clear in the introduction section.

Author Response

Review 5: 

1. Please, use the same objective from abstract in the end of introduction.

Answer: Thanks for the suggestions above. We have adhered to the suggestion for clarity of the manuscript.

2. In addition, the hypothesis of study is not clear in the introduction section.

Answer: We agree with the comment and have modified the sentence. we have described the hypothesis of our study in the last paragraph of the introduction.

Round 2

Reviewer 1 Report

Dear Authors; Most of my concerns were addressed satisfactorily. Regards.

Reviewer 4 Report

The authors correctly addressed the comments.