Acute Cardiovascular Responses to the 100-Mile Western States Endurance Run.

Abstract

To determine the acute effects of trail ultramarathon participation on central artery stiffness and hemodynamics. Forty-one participants (9F, 32M) participating in the 2023 Western States Endurance Run underwent measures of carotid-femoral pulse wave velocity (cf-PWV) and pulse wave analysis pre- and <1h post-race. Subendocardial viability ratio (SEVR) was calculated from central blood pressure (BP) waveforms. Serum was analyzed for creatine kinase (CK) activity as a measure of muscle damage. Normally distributed data are presented as mean±SD and non-normally distributed data are presented as median (interquartile range). Runners were middle-aged and generally lean (age=44±9 y, BMI=22.7±1.8 kg●m-2). There was no difference in cf-PWV from pre- to post-race (pre=6.4±1.0, post=6.2±0.85 m/s, p=0.104), a finding that persisted after adjusting for mean arterial pressure (p=0.563). Systolic and diastolic BP were lower post-race (pre=129/77±9/7, post=122/74±10/8 mmHg, ps<0.001). Augmentation index (AIx; pre=17.3±12.2, post=6.0±13.7%, p<0.001), AIx normalized to a heart rate of 75bpm (p=0.043), reflection magnitude (pre=55.5(49.0-60.8), post=45.5(41.8-48.8) %, p<0.001), and SEVR (pre=173.0(158.0-190.0), post=127.5(116.5-145.8) %, p<0.001) were reduced post-race. CK increased markedly from pre- to post-race (pre=111(85-162), post=11,973(5,049-17,954) U/L, p<0.001). Completing a 161-km trail ultramarathon does not affect central arterial stiffness and acutely reduces BP despite eliciting profound muscle damage. However, the reduced post-race SEVR suggests a short-term mismatch between myocardial work and coronary artery perfusion.