Rating of perceived exertion as a tool for managing exercise intensity during pregnancy: a scoping review

Abstract

Objective During pregnancy, international guidelines recommend ≥150 min of moderate-intensity aerobic physical activity per week, with an intensity perceived as fairly light to somewhat hard on the Borg Rating of Perceived Exertion (RPE) scale (ranging from 6 ‘no exertion’ to 20 ‘maximal exertion’, corresponding to 60% to 80% of maximum heart rate). However, the determination and monitoring of exercise intensity seem to be a particular source of confusion, and the most effective method to monitor exercise intensity remains uncertain. This study aimed to examine existing research on the correlation between the Borg RPE scale and maternal heart rate (MHR) for monitoring exercise intensity during pregnancy.Design Scoping review using the mixed methods appraisal tool (MMAT) and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.Data sources PubMed, Web of Science and SPORTDiscus were searched from 16–17 April 2023, with a subsequent search on 1 November 2023.Eligibility criteria We included studies investigating the correlation between perceived intensity on the Borg RPE scale (6–20) and MHR during exercise in pregnant individuals and written in English/Scandinavian language. There were no restrictions on publication year or study design.Data extraction and synthesis Two independent reviewers screened the articles based on title and abstract. Selected articles were read in full text and reference lists of screened articles were also checked. Out of 120 studies screened, six articles met the inclusion criteria after removing one duplicate. The results were qualitatively summarised to provide an overview of common themes and variations between studies. MMAT and GRADE assessed the risk of bias and the certainty of the evidence.Results The six studies involved a total of 260 healthy pregnant individuals (gestational week: from 16 to 38), with various exercise protocols (cycling, walking, running and resistance exercise) and intensities (from light to moderate). Three studies supported the Borg RPE scale to estimate exercise intensity during pregnancy, while three found no correlation between this scale and MHR. The certainty of the evidence was graded as low to moderate, with a potential risk of bias due to small sample sizes, incomplete outcome data and inconsistencies across studies.Conclusion The mixed results highlight the complexity of monitoring exercise intensity during pregnancy. Using both the Borg RPE scale and MHR might be better than using them separately for monitoring exercise intensity during pregnancy. Due to limited and inconsistent research, more extensive studies are needed.