Tohoku J. Exp. Med., 2002, 196 (4)

Circadian Changes in Urinary Bicarbonate, Nitric Oxide Metabolites
and pH in Female Player during Handball Camp
Involved in an Exercise, Rest and Sleep Cycle

TETSUSHI MORIGUCHI, TERUICHI SHIMOMITSU, YUKO ODAGIRI, SHIRO ICHIMURA,
JUN FUKUDA¹ and AKIO TOMODA²

Department of Preventive Medicine and Public Health, Tokyo Medical University, Tokyo 160-8402,
¹Department of Kinesiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA, and
²Department of Biochemistry, Tokyo Medical University, Tokyo 160-8402

Bicarbonate and nitric oxide levels are important humoral factors in the blood and are affected by the human body's physical condition. There are few reports, however, on changes in blood bicarbonate and nitric oxide levels during exercise and rest. Since urinary bicarbonate and nitric oxide metabolites reflect the levels of bicarbonate and nitric oxide in the blood, we studied circadian changes in 6 female athletes by monitoring their urinary pH and their levels of urinary bicarbonate and nitric oxide metabolites. Measurements were taken during exercise, rest and sleep. Six female athletes participated in a 3-day team handball training camp where they followed a schedule of exercise, rest and sleep. Urinary samples were collected immediately before and after handball training, at bed-time and upon waking. The urinary pH and levels of urinary bicarbonate and nitric oxide metabolites, including nitrite and nitrate, were examined with a blood gas analyzer and a NOx analyzer. The samples collected after handball training, as compared to the samples taken before exercise, showed a decreased pH, a decrease in levels of bicarbonate and little change in NO metabolites. During rest, urinary bicarbonate, NO metabolites and pH increased markedly in all 6 subjects. The levels of urinary bicarbonate, NO metabolites and pH significantly decreased upon waking. This study took into account the subjects' various physiological conditions when considering the significance of their changes in urinary bicarbonate, NO metabolites and pH during the 3 day handball training program. There were significant circadian changes in the urinary pH, and in the levels of urinary bicarbonate and nitric oxide metabolites, in the athletes involved in the exercise, rest and sleep program at team handball camp.

Keywords—— bicarbonate; nitric oxide metabolites; pH; handball camp

© 2002 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2002, 196, 281-291

Address for reprints: Akio Tomoda, M.D., Ph.D., Department of Biochemistry, Tokyo Medical University, Shinjuku 6-1-1, Shinkuku-ku, Tokyo 160-8402, Japan.

e-mail: tomoda@tokyo-med.ac.jp