Urinary abnormalities following karate (kumite) competitions.

Sir,

Recently, our group conducted a supplementary study on urinary abnormalities following karate (kumite) competitions in professional female athletes. In a previous issue of NDT Plus [1], our group presented data showing significantly increased proteinuria of a mixed type (albumin and beta2-microglobulin or B2M) with prominence of albumin, as a glomerular urine protein, in 18 professional (18–21 years) male karatekas. This recent study has focused on 17 healthy (16–25 years) female karatekas, who volunteered to participate in the study, in order to detect karate-induced urinary abnormalities. The competitions were held with similar characteristics of three rounds of 1.5-min duration which had been interspaced with a 10-min resting interval. Urine samples were collected just before the match and 24 h thereafter to measure total urinary protein, albumin, B2M, sodium, potassium and calcium levels. All values were compared with pre-exercise 24-h urine values. There was significantly increased mixed-type proteinuria (total protein of 190.01 ± 92.54 vs. 68.6 ± 45.51 mg/day, P = 0.001; albumin of 30.07 ± 28.81 vs. 3.71 ± 2.3 mg/day, P = 0.001; and B2M of 0.0702 ± 0.0135 vs. 0.015 ± 0.01 mg/day, P < 0.01) compared with basal levels. Furthermore, similar to previous study, daily urinary electrolytes (sodium 121.65 ± 20.40 vs. 118.21 ± 21.25, P = 0.825; potassium 41.53 ± 10.80 vs. 43.59 ± 11.86, P = 0.426; and calcium 190.88 ± 80.44 vs. 182.76 ± 87.33, P = 0.755) excretions did not change significantly following the competitions. Urinary glucose in both pre- and post-exercise urine samples was not found. Based on the aforementioned data, it seems that karate (kumite) competition in both genders does not have significant influence on some urinary electrolyte and substance excretions. This finding may be attributed to appropriate tubular transport, short duration of competitions, adequate hydration of athletes and efficacious regulatory mechanisms in order to maintain normal blood levels [2]. However, because of the intensity of this exercise which results in sympathetic stimulation, the glomerular permeability and protein excretion may be changed [3,4]. We recommend further researches on karate-induced urinary abnormalities.

Conflict of interest statement. None declared.