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Effect of FIO2 on Physiological Responses and Cycling Performance at Moderate Altitude


Medicine & Science in Sports & Exercise: July 2003 - Volume 35 - Issue 7 - p 1153-1159
doi: 10.1249/01.MSS.0000074495.34243.B5
BASIC SCIENCES: Original Investigations

WILBER, R. L., P. L. HOLM, D. M. MORRIS, G. M. DALLAM, and S. D. CALLAN. Effect of FIO2 on Physiological Responses and Cycling Performance at Moderate Altitude. Med. Sci. Sports Exerc., Vol. 35, No. 7, pp. 1153–1159, 2003.

Purpose To evaluate physiological responses and exercise performance during a “live high–train low via supplemental oxygen” (LH + TLO2) interval workout in trained endurance athletes.

Methods Subjects (N = 19) were trained male cyclists who were permanent residents of moderate altitude (1800–1900 m). Testing was conducted at 1860 m (PB 610–612 Torr, PIO2 ∼128 Torr). Subjects completed three randomized, single-blind trials in which they performed a standardized interval workout while inspiring a medical-grade gas with FIO2 0.21 (PIO2 ∼128 Torr), FIO2 0.26 (PIO2 ∼159 Torr), and FIO2 0.60 (PIO2 ∼366 Torr). The standardized interval workout consisted of 6 × 100 kJ performed on a dynamically calibrated cycle ergometer at a self-selected workload and pedaling cadence with a work:recovery ratio of 1:1.5.

Results Compared with the control trial (21% O2), average total time (min:s) for the 100-kJ work interval was 5% and 8% (P < 0.05) faster in the 26% O2 and 60% O2 trials, respectively. Consistent with the improvements in total time were increments in power output (W) equivalent to 5% (26% O2 trial) and 9% (60% O2 trial; P < 0.05). Whole-body O2 (L·min−1) was higher by 7% and 14% (P < 0.05) in the 26% O2 and 60% O2 trials, respectively, and was highly correlated to the improvement in power output (r = 0.85, P < 0.05). Arterial oxyhemoglobin saturation (SpO2) was significantly higher by 5% (26% O2) and 8% (60% O2) in the supplemental oxygen trials.

Conclusion We concluded that a typical LH + TLO2 training session results in significant increases in arterial oxyhemoglobin saturation, O2 and average power output contributing to a significant improvement in exercise performance.

1Athlete Performance Laboratory, United States Olympic Committee, Colorado Springs, CO;

2Department of Exercise Science, Health Promotion and Recreation, Colorado State University–Pueblo, Pueblo, CO; and

3Sport Science Department, USA Cycling, Colorado Springs, CO

Address for correspondence: Randall L. Wilber, Ph.D., Athlete Performance Laboratory, Sport Science Division, United States Olympic Committee, One Olympic Plaza, Colorado Springs, CO, 80909; E-mail:

Submitted for publication December 2002.

Accepted for publication February 2003.

©2003The American College of Sports Medicine