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Rapid Moderate Altitude De-acclimatization and the Effect of Exercise Prescription to Mitigate Loss: 1383Board #119 June 1 9:30 AM - 11:00 AM

Brothers, Michael D.; LaChapelle, James A.; Wynkoop, Bryan S.; Schindler, Cole R.; Grossmann, Elizabeth C.; Apt, Tyner M.; Rudico, Erlyn R.; Zupan, Michael F.; Nelson, Jeffery L.

Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 285
doi: 10.1249/01.MSS.0000400783.66720.96
A-37 Free Communication/Poster - High Altitude Physiology: JUNE 1, 2011 7:30 AM - 12:30 PM: ROOM: Hall B

U.S. Air Force Academy, USAF Academy, CO.


(No relationships reported)

Astronauts and high-altitude (>4000m) residents experience neocytolysis - a rapid reduction in total hemoglobin mass (THM) - upon return to sea level (SL; <300m). Whether this rapid de-acclimatization occurs among moderate altitude (MA; ∼2210m) residents, and whether an exercise intervention can mitigate this loss is unknown.

PURPOSE: This study examined changes in THM among MA residents who completed various 'exercise prescriptions' during a three-week winter break spent at SL. Based on previous studies, we expected all subject's THM to decrease significantly; however, we hypothesized cadets performing high-intensity aerobic exercise would minimize THM loss.

METHODS: Fifty three cadet subjects (39 male, 14 female) age 20.5 + 1.5 years participated in the study. Each subject was scheduled for THM assessment using the optimized CO re-breathing protocol twice the month prior to departing for SL, and twice upon their first week returning to MA. Subjects were classified into one of three groups: 'control' (moderate exercise), 'interval' (high intensity), or 'endurance' (high volume). Statistical significance was set at p < 0.05.

RESULTS: All subjects had a significant (p < 0.001) loss in THM over winter break, losing 3.7% (-28.3 + 29.3g) on average. The 'interval' group lost the least, which neared statistical significance (p = 0.061):



CONCLUSIONS: All subjects' THM significantly decreased despite exercise intervention while at SL. However, exercise intervention attenuated THM loss and the interval cohort's decrease neared statistical significance.

Disclaimer: the views expressed are those of the authors and do not reflect the official policy or position of the United States Air Force, the Department of Defense, or the US Government.

© 2011 American College of Sports Medicine