This manuscript addresses an important and underexplored question regarding the feasibility of interrupting evening sedentary behaviour with brief activity breaks in a free-living setting.

The topic is timely and relevant, the intervention is thoughtfully theory-informed, and the use of multimodal assessment is a notable strength.

In particular, the focus on evening sedentary behaviour and the effort to translate laboratory findings into a real-world context represent valuable contributions to the field.

Overall, I found the manuscript promising and believe it has merit. At the same time, several methodological and interpretive issues, if addressed, would substantially strengthen the manuscript.

My comments below are intended in a constructive spirit to support further improvement.

I therefore recommend major revision.

Introduction
1. The citation supporting the statement regarding evening consumption of the largest meal of the day (Reference 17; Lines 57–60) may benefit from reconsideration in terms of content and timing.

1. The study referenced around Line 62 would benefit from slightly more contextual description regarding population, intervention, and outcomes, particularly given its relevance for motivating the present study.

Methods
3. It may be helpful to provide additional justification for the feasibility threshold introduced in Lines 158–160.

The criterion of four activity breaks in at least half of participants is clearly pre-specified, but its rationale would benefit from further explanation and supporting citation.

1. I would appreciate slightly greater transparency regarding statistical assumptions (Lines 222–234). Given the small sample size and the nature of several outcome variables, it may be useful to indicate whether distributional assumptions (normality) were assessed.

2. As the MOVA app appears central to the intervention, a slightly fuller description of its functionality (Lines 126–134 and 163–165) would improve methodological clarity. Readers may benefit from additional information on how it works, adherence tracking, and interpretation of app-derived data.

Results
6. One important point that may benefit from stronger discussion is the discrepancy between reported increases in activity breaks and the relatively limited changes in objectively measured sedentary time and physical activity outcomes (Lines 245–261; Tables 2 and 3).

Further discussion of how these findings should be reconciled would strengthen interpretation of the intervention’s behavioural impact.

1. Relatedly, the discrepancy between self-reported activity breaks, app-recorded breaks, and accelerometer-derived estimates (Lines 245–257) raises important questions regarding measurement validity. Some additional reflection on the implications of these differences would be valuable.

2. The interpretation of secondary physiological outcomes may benefit from slightly more cautious framing.

Given the pilot nature of the study and the limited changes observed in glucose and blood pressure outcomes, it may be helpful to ensure that these findings are consistently presented as exploratory.

Discussion
9. The discussion may benefit from further reflection on whether the intervention dose and intensity were sufficient to plausibly influence glycaemic and blood pressure outcomes, particularly given the largely null findings.

1. I would encourage the authors to expand discussion of longer-term feasibility and sustainability, particularly in light of the apparent decline in adherence over time (Lines 296–304 and 324–349), as this seems highly relevant to the translational implications of the work.

2. Around Lines 300–305, where adherence findings are discussed in relation to Smith et al., it may be worth checking whether a citation is missing or whether citation placement could be clarified.

3. Finally, the discussion may benefit from brief consideration of the exercise snacking literature and from reflection on other populations in whom this intervention may be particularly relevant, particularly those at higher metabolic risk.