"Live High-Train Low" (LHTL) altitude acclimatization has been shown to increase athletic endurance performance; however, this type of training has been associated with decreases in mucosal immune system function as measured by salivary IgA antibodies (Tiollier et al., 2005). Physiological effects of altitude, strenuous training, and isolation from family could be additive stresses that depress the immune system (Walsh et al., 2006). Babcock and Kirby (2008) have shown that a simulated intermittent altitude exposure (IE) device utilized for short durations has the same performance enhancing effects as LHTL; however, the effect of IE via re-breathing on running performance and maintenance of immune system functionality has not been established. PURPOSE: To determine the effects of IE on running performance and the mucosal immune system. METHODS: Sixteen well-trained male runners/triathletes were exposed to the hypoxic stimulus for fifteen days. IE was administered using a simple device (Alto2Lab, Pharma Pacific, Inc.) consisting of a breathing tube attached to an open-ended silo containing carbon-dioxide absorptive soda lime. Oxygen saturation was monitored with a pulse oximeter, and progressively reduced (90% on Day 1 to 77% on Day 6-15; equivalent altitudes equal 3600-6200 m) for treatment group 1 (LON) or held constant for treatment group 2 (SHO, 90%; Day 1-15); the control group (CON) was not exposed to the IE. Time to complete a 10K race was tested at baseline and post-treatment. Salivary IgA was compared from baseline to post-treatment using ELISA. Comparisons between groups were made using the non-parametric unpaired Mann-Whitney test. RESULTS: Time to complete the 10K race significantly decreased for the LON treatment group compared to CON (p<0.05). There was a non-significant improvement in run performance for the SHO group. No significant decrease in salivary IgA antibodies was detected in any of the groups (p<0.05). CONCLUSION: A simple, cost-effective, device can elicit the same performance enhancing effects as LHTL in a much shorter time, without mucosal immune system compromise. Such a method to simulate altitude exposure while remaining at sea-level is considered highly desirable among competitive endurance athletes.
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