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Association of Military Training with Oxidative Stress and Overreaching

TANSKANEN, MINNA M.1; UUSITALO, ARJA L.2; KINNUNEN, HANNU3; HÄKKINEN, KEIJO1; KYRÖLÄINEN, HEIKKI1; ATALAY, MUSTAFA4

Medicine & Science in Sports & Exercise: August 2011 - Volume 43 - Issue 8 - pp 1552-1560
doi: 10.1249/MSS.0b013e3182106d81
Applied Sciences

ABSTRACT: We hypothesized that increased oxidative stress and disrupted redox balance may be predisposing factors and markers for overreaching (OR).

Purpose: The study's purpose was to examine whether oxidative stress markers and antioxidant status and physical fitness are related to OR during an 8-wk military basic training (BT) period.

Methods: Oxidative stress and antioxidant status were evaluated in the beginning and after 4 and 7 wk of training in 35 males (age = 19.7 ± 0.3 yr) at rest and immediately after a 45-min submaximal exercise. Physical activity (PA) was monitored by an accelerometer throughout BT. Indicators of OR were also examined.

Results: From baseline to week 4, increased daytime moderate to vigorous PA led to concomitant decreases in the ratio of oxidized to total glutathione (GSSG/TGSH) and GSSG. After 4 wk of BT, GSSG/TGSH and GSSG returned to the baseline values at rest, whereas PA remained unchanged. At every time point, acute exercise decreased TGSH and increased GSSG and GSSG/TGSH, whereas a decrease was observed in antioxidant capacity after 4 wk of training. In the beginning of BT, OR subjects (11 of the 35 males) had higher GSSG, GSSG/TGSH, and malondialdehyde (a marker of lipid peroxidation) at rest (P < 0.01-0.05) and lower response of GSSG and GSSG/TGSH ratio (P < 0.01) to exercise than non-OR subjects. Moreover, OR subjects had higher PA during BT than non-OR (P < 0.05).

Conclusions: The sustained training load during the last 4 wk of BT led to oxidative stress observable both at rest and after submaximal exercise. Increased oxidative stress may be a marker of insufficient recovery leading possibly to OR.

1Department of Biology of Physical Activity, University of Jyväskylä, FINLAND; 2Department of Clinical Physiology and Nuclear Medicine, Helsinki University Hospital, Helsinki, FINLAND; 3Polar Electro Oy, Kempele, FINLAND; and 4Institute of Biomedicine/Physiology, University of Eastern Finland, Kuopio, FINLAND

Address for correspondence: Minna M. Tanskanen, M.Sc., Department of Biology of Physical Activity, University of Jyväskylä, Kidekuja 2, Snowpolis, 88610 Vuokatti, Finland; E-mail: minna.m.tanskanen@jyu.fi.

Submitted for publication September 2010.

Accepted for publication January 2011.

©2011The American College of Sports Medicine