Sex-specific Physiological Responses To Ultramarathon

Abstract

PURPOSE. Despite a growing body of literature on the physiological response to ultra-marathon, there is a paucity of data in female athletes. This study assessed the female physiological response to ultra-marathon and compared perturbations to a group of race- and performance-matched males. METHODS. Data were examined from a cohort of 53 individuals who contested an ultra-marathon trail race at the Ultra Trail du Mont-Blanc (UTMB®) in 2018/19. Before and within 2-h of the finish, subjects underwent physiological assessments including: Blood sampling (creatine kinase, CK-MB; cardiac troponin I, cTnI; brain natriuretic peptide, BNP, creatinine, Cr); pulmonary function testing (spirometric indices, exhaled NO, diffusing capacities, mouth pressures); and transthoracic ultrasound (lung comet tails, cardiac function). Data from eight female finishers (age = 36.6 ± 6.9 y; finish time = 30:57 ± 11:36 hh:mm) were compared to a group of eight time-matched males (age = 40.3 ± 8.3 y; finish time = 30:46 ± 10:32 hh:mm). RESULTS. Females exhibited significant post-race hematological changes in BNP (25.8 ± 14.6 vs. 140.9 ± 102.7 pg/mL; p = 0.017) and CK-MB (3.3 ± 2.4 vs. 74.6 ± 49.6 IU/L; p = 0.005), whereas males exhibited significant post-race hematological changes in BNP (26.6 ± 17.5 vs. 96.4 ± 51.9 pg/mL; p = 0.007), CK-MB (7.2 ± 3.9 vs. 108.8 ± 37.4 IU/L; p < 0.001), cTnI (0.01 ± 0.01 vs. 0.05 ± 0.05 ng/mL; p = 0.033), and Cr (1.06 ± 0.19 vs. 1.23 ± 0.24 mg/dL; p = 0.014). Post-race peak expiratory flows decreased in both groups; however, only males exhibited reductions in lung diffusing capacities (DLCO = 34.4 ± 5.7 vs. 29.2 ± 6.9 mL/min/mmHg, p = 0.002; DLNO = 179.1 ± 26.2 vs. 152.8 ± 33.4 mL/min/mmHg, p = 0.001) and pulmonary capillary blood volume (77.4 ± 16.7 vs. 57.3 ± 16.1 mL; p < 0.001). Males, but not females, exhibited a significant post-race increase in the number of lung comet tails (2.4 ± 2.2 vs. 8.3 ± 2.7; p = 0.001). CONCLUSION. Participation in an ultra-marathon negatively affects numerous aspects of physiological function but evokes more extensive perturbations in males compared to females with similar race performances.