Pedagogical modeling of the effect of prolonged work with digital devices on the physiological state of the cardiorespiratory system of students

Aim and research questions Aim: to show which combinations of “digital exposure × cardiorespiratory (autonomic) outcome” and “pedagogical measure × outcome” have been studied in school pupils and university students and which remain empty. RQ1. How is the literature structured by topic, time, country and source? RQ2. Which cells of Table A (exposure × outcome) and Table B (pedagogical measure × outcome) are filled and which are empty? RQ3. What share of the evidence is experimental and what share is observational? RQ4. How are Kazakhstan and the CIS represented in international databases? Hypotheses and thresholds (set before the search) No. Hypothesis Criterion H1 Studies with cardiorespiratory outcomes in students are fewer than studies on mental health and on obesity at the same exposure Scopus count for the cardiorespiratory block is below one third of the count for the mental-health block and of the count for the obesity block P1 Pedagogical measures are rarely tested against objective physiological outcomes Fewer than half of the cells of Table B are filled, and most filled cells hold a single study P2 Most of the evidence is observational At least 70% of group A documents are observational P3 Kazakhstan and the CIS are poorly represented Share of Scopus records with a Kazakhstan affiliation below 2% 3. Eligibility and groups Group Criterion A Pupils or university students; digital device use studied (including distance learning); objective instrument-measured cardiorespiratory or autonomic outcome C Students and a device exposure, but the outcome is subjective or not cardiorespiratory; or objective outcome in non-students D Off topic Sources and search Scopus, PubMed and OpenAlex (Web of Science if access exists), publication years 2010–2026, no language limit. Scopus string: TITLE-ABS-KEY((student* OR pupil* OR schoolchild* OR adolescen* OR "young adults" OR "young adult" OR undergraduate* OR "university students" OR "college students" OR "primary school" OR "primary schools" OR "secondary school" OR "secondary schools") AND ("screen time" OR "screen use" OR "digital device" OR "digital devices" OR "digital screen" OR "digital screens" OR "computer use" OR "computer work" OR "visual display" OR smartphone* OR "mobile phone" OR "mobile phones" OR tablet* OR "e-learning" OR "online learning" OR "distance learning" OR "remote learning" OR "digital learning" OR "prolonged sitting" OR "screen-based" OR gadget*) AND (cardiorespiratory OR "cardio-respiratory" OR cardiovascular OR "heart rate" OR "heart rate variability" OR hrv OR "blood pressure" OR hypertension OR autonomic OR "respiratory function" OR "lung function" OR "pulmonary function" OR spirometry OR "vital capacity" OR "oxygen saturation" OR "aerobic fitness" OR vo2 OR "physiological state" OR "functional state")) AND PUBYEAR > 2009 AND PUBYEAR < 2027 The PubMed and OpenAlex strings are in the search log 5. Procedure 1.Run each search; record date, string, filters and number of results in the search log; take a screenshot of the result count; export every record with abstracts. 2.Import all exports into Zotero. Remove duplicates with Duplicate Items (merge), then check remaining pairs by DOI and by title and year; record the numbers in the de-duplication log. 3.Screen titles and abstracts in Rayyan (or an Excel sheet) with two independent screeners, blinded to each other. Use the reason codes of the screening log. Resolve disagreements by discussion; a third person decides if needed. 4.Pilot the extraction form on 15 records with both coders; revise the rules; then code all remaining records independently. 5.Compute Cohen’s kappa in Excel with the kappa sheet; report the 95% CI. 6.Resolve disagreements in the consensus log, with the rule applied for each. 7.Check group A records in full text (full-text check log). 8.Build Tables A and B with a pivot table. Export keywords for VOSviewer from Zotero as RIS and build the map with the settings given in the manuscript. 6. Instructions for the second coder Decide from title and abstract using the criteria of section 3. Fill the other columns for group A only. Do not look at the other coder’s codes and do not discuss records before returning the file. If in doubt, choose the closest option and give the reason in Notes.