The Influence of Light and Physical Activity on the Timing and Duration of Sleep: Insights from a Natural Model of Dance Training in Shifts

Round 1

Reviewer 1 Report

The present manuscript describes "The influence of light and physical activity on the timing and duration of sleep: Insights from a natural model of dance training in shifts". The authors have studied influence of factors such as physical activity and exposure at different intensities. Different environments influenced the sleep pattern of dancers, I recommend publishing this good manuscript by replying to some comments.

*I recommend showing more clearly in the text or methodology the difference between vigorous and moderate activity

*improve the quality of the conclusion by including more qualitative and quantitative factors in the study.

*improve the quality of the conclusion including the characterization results of the material produced.

Author Response

Thank you, Reviewer 1, for your constructive comments. As stated at the beginning of the uploaded document, we decided to submit the same global file of responses to reviewers and editor's comment because several responses address general issues that might be useful for the evaluation of the manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

The study described is a field study on the relationships between sleep, training schedules and environmental factors. It is undoubtly useful to investigate real life situations, especially if two groups with only one difference (training time) can be compared. The results are interesting and well presented. I have one main concern and that is the argumentation behind the causal explanations discussed for instance in lines 185 and later. The correlation between morning light exposure and sleep end might, in my opinion, be in two directions. More light could induce a phase advance in sleep timing, on the other hand, early rising may increase light exposure in the morning. The same holds for late night light exposure and late sleep. These questions also arise from line 216, and  lines 326 and later in the conclusion paragraph. Would the authors please be so kind to explain why this conclusion is drawn and why they think there is a causal relationship between light and sleep timing and not the other way around, sleep timing and light exposure? Actually, also the title is already indicating a biased conclusion in my opinion, based on correlations only it is difficult to conclude on causal relationship in one direction. Maybe the limitations of a correlational study could be discussed, if there is no proper argument.

 One other question: I do not understand item b) in line 215. Could the authors formulate this a bit more clear?

Author Response

Thank you, Reviewer 2, for your constructive comments. As stated at the beginning of the uploaded document, we decided to submit the same global file of responses to reviewers and editor's comment because several responses address general issues that might be useful for the evaluation of the manuscript.

Author Response File: Author Response.docx