Author(s): ORESKÁ, L., SEDLIAK, M., KUNDEKOVÁ B., OLIVA V., BUZGÓ G., Institution: FACULTY OF PHYSICAL EDUCATION AND SPORTS, COMENIUS UNIVERSITY, Country: SLOVAKIA, Abstract-ID: 2161

INTRODUCTION:
Endurance running performance reflects a complex interaction of physiological, biomechanical, and sociocultural factors, with biological sex and ageing among the strongest determinants across the lifespan. Emerging evidence also suggests that Relative Energy Deficiency in Sport (REDs) is increasingly prevalent in both young and master endurance runners. However, it remains unclear how long-term endurance training influences REDs risk, skeletal muscle characteristics, and physiological ageing compared with inactivity. Therefore, the study examined how biological sex and ageing influence physiological performance, skeletal muscle characteristics, bone health, and REDs risk in young and master endurance runners. Secondly, we compared endurance runners with age- and sex-matched inactive controls to determine whether long-term endurance training preserves physiological function and attenuates age-related decline across the lifespan.
METHODS:
This cross-sectional study protocol examined 80 participants stratified by sex, age (20–35 vs. 65–80 years), and training status into : (1) Young Male Endurance Runners (n=10), (2) Master Male Endurance Runners (n=10), (3) Young Male Age-Matched Controls (n=10), (4) Elderly Male Age-Matched Controls, (5) Young Fe-male Endurance Runners, (6) Master Female Endurance Runners (n=10), (7) Young Female Age-Matched Controls (n=10), and (8) Elderly Female Age-Matched Controls (n=10). Assessments comprised DXA-bone (BMD) based body composition analysis, isometric knee extension dynamometry, blood biomarkers (Insulin, HbA1c, cholesterol, sex hormones, etc.) and cardiorespiratory fitness testing. All groups filled LEAF and LEAM questionnaires.
RESULTS:
Results
As expected, despite the sex, both young and master endurance runners demonstrated higher VO2max and compared with age-matched inactive controls. An effect long-term exercise was visible where all running group have significantly lower serum insulin and HbA1c, despite the sex differences. Yet, no significant changes were observed in the cholesterol. Significant differences were observed in the sex hormones (testosterone, estradiol, HSBG) according to age and sex. Associations between selected objective REDs risk markers and physiological, endocrine, and body composition outcomes were examined using correlation and multivariable regression analyses.
CONCLUSION:
This study provides deeper insight into how ageing and sex influence endurance physiology and REDs susceptibility, and whether long-term endurance training preserves functional capacity across the lifespan. Surprisingly, inactive young groups were similarly strong at the knee isometric extension as young, trained groups. Similarly, there were no significant differences with elderly trained and inactive group. However. there were observed difference between sexes.
Acknowledgement
The study was funded by the Slovak Research and Development Agency (Grant no. APVV-21-0164), VEGA 1/0554/24, and VEGA 1/0482/23.