Hypoxic Ventilatory Response Does Not Predict Performance At Moderate Altitude In Elite Distance Runners

Abstract

Research suggests that individuals with strong hypoxic ventilatory responsiveness are better suited for mountain climbing performance at high altitudes. We asked if this relationship between hypoxic ventilatory response (HVR) and endurance exercise performance would extend to racing performance of elite distance runners at moderate altitude. PURPOSE: To test the hypothesis that endurance performance at moderate altitude is related to initial levels of and/or changes in HVR in a group of elite distance runners. METHODS: Twenty-one national class U.S. distance runners (13 M, 8 F) completed a 28-day altitude training intervention in Deer Valley, Utah, elevation 2500m, following a "Live High - Train Low" training model. Isocapnic HVR was measured in the one week prior to and within 72 hours upon return from altitude. Endurance performance was measured using 3km time trials completed on 400m all-weather tracks at sea-level (SL) one day prior to departure for altitude, and twice at an altitude of 2100m - 48 hours after arrival to altitude (ALT1), and on day 23 of the altitude intervention (ALT4). RESULTS: HVR was significantly increased from pre- to post-altitude (0.21±0.04 vs. 0.40±0.06 ΔL·min-1·Δ%SaO2-1, p<0.05). ALT1 3km performance time was significantly slower than that measured at SL (9.53±0.68 vs. 8.76±0.63 min). ALT4 3km time was significantly faster than ALT1 3km time (9.34 ± 0.68 min but remained significantly slower than SL 3km time. HVR was not significantly correlated with 3km performance time at either ALT1 (r = -0.25 M; r = -0.14 F) or ALT4 (r = 0.05 M; r = -0.32 F). In addition, pre-altitude HVR was not significantly related to the change in 3km time from SL to ALT1 (r = -0.28 M; r = 0.34 F). The change in HVR after chronic altitude exposure (pre- to post-altitude) was not significantly correlated with the change in 3km performance time from ALT1 to ALT4 (r = 0.24). CONCLUSIONS: In contrast to the positive HVR-performance relationship seen in mountain climbers at high altitude, it appears that the performance of elite distance runners at moderate altitude does not depend on initial levels of or changes in hypoxic ventilatory response. Supported by US Olympic Committee grant SST97-ATH-007, a grant from USA Track and Field, and institutional support from Presbyterian Hospital of Dallas and Indiana University.