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Change in the capability of reactive oxygen species production by neutrophils following weight reduction in female judoists
  1. Makoto Yaegaki1,
  2. Takashi Umeda1,
  3. Ippei Takahashi1,
  4. Masashi Matsuzaka1,
  5. Norio Sugawara1,
  6. Sen Shimaya1,
  7. Masaru Tanabe2,
  8. Arata Kojima1,
  9. Noriko Mochida1,
  10. Yousuke Yamamoto1,
  11. Shigeyuki Nakaji1
  1. 1Department of Social Medicine, Hirosaki University School of Medicine, Zaifu-cho, Hirosaki, Aomori, Japan
  2. 2Department of Physical Education, Nippon Sport Science University, Fukasawa, Setagaya, Tokyo, Japan
  1. Correspondence to:
 Professor S Nakaji
 Department of Social Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036–8562, Japan; nakaji{at}


Objective: Athletes undergoing weight reduction are recognised as being more prone to infection. Few studies exist for athletes on the weight reduction-mediated changes in neutrophil function and related activities such as reactive oxygen species (ROS) production capability, phagocytic activity (PA) and serum opsonic activity (SOA).

Methods: 16 Japanese female university judoists were examined in the early morning of the first day (pre-values) and the last day (post-values) of a 20-day pre-competition training period. Of the 16 subjects, 8 needed to reduce weight (WR group) and the other 8 did not (control group). The parameters assessed were the neutrophil count, serum immunoglobulins and complements, myogenic enzymes, ROS production capability, PA and SOA.

Results: Comparing the post-values with the pre-values, ROS production significantly increased in both groups (p<0.01 for both). PA significantly decreased in the WR group (p<0.05); it also decreased in the control group but the decrease was not significant. SOA significantly increased in the control group (p<0.05), but showed no significant change in the WR group.

Conclusions: The changes in the WR group were probably a direct consequence of the weight-reduction regimen coupled with the exercise regimen, suggesting that neutrophil parameters (ROS production, PA and SOA) had tended to deviate from their typical compensatory changes to maintain immune system homoeostasis.

  • FFM, fat-free body mass
  • FITC, fluorescein isothiocyanate
  • HBSS, Hank’s balanced salt solution
  • HE, hydroethidine
  • OZ, opsonised zymosan
  • PA, phagocytic activity
  • ROS, reactive oxygen species
  • SOA, serum opsonic activity
  • WR, weight reduction

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  • Published Online First 15 January 2007

  • Competing interests: None declared.