RELATIONSHIP BETWEEN RUFFIER INDEX-DERIVED FITNESS LEVELS AND RESTING CARDIOVASCULAR PERFORMANCE IN YOUNG ADULTS

Abstract

Purpose of the work. Physical fitness plays a crucial role in cardiovascular health, influencing stroke volume (SV), cardiac output (CO), heart rate (HR), and blood pressure. The Ruffier Index (RI) is a simple, field-based measure of cardiovascular efficiency, but evidence linking RI-assessed fitness to resting SV and CO in young adults is limited. This study aimed to investigate the relationship between RI-derived fitness levels and resting cardiovascular parameters (SV, CO, HR, SBP, DBP) in healthy young adults, and to examine potential sex-specific differences.

Methodology. A cross-sectional study was conducted with 51 healthy students (28 women, 23 men) from Pomeranian University in Słupsk, Poland (mean age: 20.8 ± 4.2 years for women; 19.9 ± 2.9 years for men). Physical fitness was classified using the RI into very good, good, average, and poor categories. Resting SBP, DBP, HR, SV, and CO were measured under standardised conditions. SV was calculated using the Starr formula, and CO was derived from SV × HR. Statistical analyses included ANOVA, post hoc Tukey tests, Pearson correlations, and linear/multivariate regression models with sex and blood pressure as covariates.

Scientific novelty. Most participants demonstrated average fitness, with very good fitness observed only in one male participant. Stroke volume decreased progressively as fitness declined in both sexes, while cardiac output increased among participants with lower fitness, indicating compensatory mechanisms via increased heart rate. Women with poor fitness had the highest resting CO (5485 ± 940 ml/min) and lowest SV (57.4 ± 7.9 ml), while men with poor fitness had CO of 5418 ± 510 ml/min and SV of 63.4 ± 3.1 ml. Significant negative correlations were found between RI and SV (women: r = −0.52; men: r = −0.48), and moderate positive correlations between RI and CO (women: r = 0.46; men: r = 0.41). Linear and multivariate regression confirmed RI as a significant predictor of SV and CO (p < 0.01). Sex differences were observed, with men exhibiting higher SV and slightly higher SBP.

Conclusions. Higher RI-assessed fitness is associated with greater stroke volume, lower cardiac output at rest, and more efficient myocardial function. Individuals with lower fitness compensate via increased HR, resulting in higher cardiovascular workload. These findings highlight the utility of RI as a practical tool for assessing cardiovascular efficiency in young adults and reinforce the importance of promoting regular physical activity to enhance cardiac function. Future studies should involve larger, longitudinal cohorts and include comprehensive physiological assessments.