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E-14 Free Communication/Slide - Human Performance II: JUNE 4, 2010 8: 00 AM - 9: 45 AM: ROOM: 324

Association Of Changes In Oxidative Stress And Antioxidant Status With Overreaching During Strenuous Military Training

874

June 4 8:15 AM - 8:30 AM

Tanskanen, Minna1; Uusitalo, Arja2; Kyröläinen, Heikki1; Atalay, Mustafa FACSM3

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Medicine & Science in Sports & Exercise: May 2010 - Volume 42 - Issue 5 - p 90
doi: 10.1249/01.MSS.0000385634.73257.60
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PURPOSE: To test the hypothesis that intensive military training increases oxidative stress and decreases antioxidant capacity among conscripts during an 8-week basic training (BT) period. An additional aim was to determine whether oxidative stress markers and antioxidant status are related to incidence of overreaching (OR) during BT.

METHODS: Plasma protein carbonyls (PCA), nitrotyrosine, malondialdehyde (MDA), oxygen radical absorbance capacity (ORAC), total glutathione (TGSH), oxidized glutathione (GSSG) and GSSG/TGSH ratio were evaluated at rest and immediately after a 45-min submaximal exercise test at 70% of VO2max at baseline and after 4 and 7 weeks of training in 57 males (19.7±0.3 yrs). In addition, indicators of OR were examined. OR subjects had to fulfill three of five criteria; decreased VO2max, increased RPE in 45-min submaximal test or absence due to sickness from these tests, increased somatic or emotional symptoms of OR and high incidence of absence due to sickness from daily training.

RESULTS: Among 35 subjects who completed all tests, ORAC, GSSG and GSSG/TGSH decreased at rest after 4 weeks of training (p<0.05). ORAC and GSSG returned to baseline values during the second half of BT (p<0.05), but GSSG/TGSH did not. However, nitrotyrosine, PCA, MDA, and TGSH remained unchanged. Acute exercise induced a decrease in TGSH and an increase in GSSG/TGSH at every time point (p<0.001), while a decrease in ORAC was observed after 4 weeks of training (p<0.05). Out of 57 subjects, 33% were classified as OR at the end of BT. At baseline, OR had higher MDA (P<0.05), GSSG (P<0.01) and GSSG/TGSH ratio (P<0.05) than no OR at rest. On the other hand, OR subjects demonstrated a lower response of GSSG and GSSG/TGSH (p<0.05) to acute submaximal exercise. In response to training, increase in ORAC (P<0.05) was observed from wk4 to wk7 in no OR, while OR subjects exhibited decrease in MDA (P<0.05), GSSG (P<0.001) and GSSG/TGSH ratio (P<0.01) from baseline to wk4.

CONCLUSIONS: The overall training load of BT did not increase oxidative stress but increased antioxidant capacity among no OR and those subjects who were in good health during BT. Subjects who developed OR demonstrated higher baseline oxidative stress, which may suggest that increased oxidative stress may contribute toward the pathophysiology of the overreaching.

© 2010 American College of Sports Medicine