Saudi Journal of Kidney Diseases and Transplantation

: 2011  |  Volume : 22  |  Issue : 6  |  Page : 1253--1255

Hematuria following Karate (Kumite) competitions in females

Mona Sarhadi1, Suzan Sanavi2, Reza Afshar3,  
1 Department of Sport Physiology, Islamic Azad University, Tehran, Iran
2 Clinical Department, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
3 Department of Nephrology, Shahed University, Tehran, Iran

Correspondence Address:
Suzan Sanavi
Clinical Department, University of Social Welfare and Rehabilitation Sciences, Tehran

How to cite this article:
Sarhadi M, Sanavi S, Afshar R. Hematuria following Karate (Kumite) competitions in females.Saudi J Kidney Dis Transpl 2011;22:1253-1255

How to cite this URL:
Sarhadi M, Sanavi S, Afshar R. Hematuria following Karate (Kumite) competitions in females. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2022 Oct 1 ];22:1253-1255
Available from:

Full Text

To the Editor ,

Hematuria is a common finding after long strenuous exertion. Therefore, the prevalence of hematuria is higher in athletes than in the general population. This phenomenon is usually self-limiting and resolution of sport-related hematuria is characteristically spontaneous and rapid. [1] The first, formal description of exercise-induced hematuria goes back to 1910, when red blood cells were detected in the urine of 18 marathon runners after a 40 kilometer race. Since then, exercise induced hematuria has been described in association with a variety of different sports both in contact sports (boxing, soccer, and American football) and non-contact sports (running, rowing, and swimming). [2] Sports-induced hematuria is influenced by the duration as well as intensity of exercise. During intense exercise, it has been reported that renal blood flow may drop from normal 1000 mL/min to 200 mL/min. This decline is due to shunting of blood to muscular vasculature which is associated with a concomitant release of epinephrine and nor-epinephrine. These hormones mediate renal vasoconstriction of the afferent and efferent glomerular arterioles. A decrease in renal blood flow can lead to renal ischemia which results in increased glomerular basement membrane permeability, thus allowing the passage of red blood cells into the urine. [3],[4] Other mechanisms which can induce post exercise hematuria/hemoglobinuria are increased body temperature, the destruction of erythrocytes (hemolysis), and increased production of free radicals. [5],[6]

This study investigates the effect of martial arts (Karate sub-division) in precipitating hematuria among female karatekas. Karate (Kumite) is a short duration contact exercise with controlled strokes. Its effect on urinary system has not been fully investigated and there are few reports, particularly in women, regarding this issue. [7],[8] To our knowledge, this is the first investigation about Karate-induced hematuria in females.

Out of 40 professional Iranian female karatekas with primary normal urine analysis, 17 healthy female karatekas aged between 16 to 25 years (mean age of 19.8 ± 0.57) and having similar physical characteristics volunteered for this study. All subjects were healthy, non-smokers, and without any previous history of renal, gynecologic and bleeding disorders. None of them was in menstrual period during the competition. Training programs had been discontinued 24 hours before starting the match. The practitioners were recommended to drink adequate fluids to prevent dehydration. All competitors emptied their bladder before the match. The participants competed in three rounds, each lasting about three minutes. They had 10-min resting interval between each round. Urine samples were collected just before the competition, immediately after and 1, 3, and 24 hours after the match. Presence of urinary red cells was assessed in the urinary sediment by light microscopy. Urinary red cells were not detected in pre and post-exercise urine samples in any of them.

The physical characteristics of Karate practitioners are given in [Table 1]. Demographic data were analyzed using the Statistical Package for the Social Sciences (SPSS) software v. 16. The results were expressed as mean ± SD.{Table 1}

Hematuria (gross or microscopic) is the most common presenting sign of renal injury which can also occur during strenuous exercise. In athletes, it may be of both glomerular (dysmorphic) and non-glomerular origin. [9] In other words, exercise-induced hematuria can originate in the kidney, bladder, urethra, or prostate. [10]

Injuries happen often due to movements and shaking of kidneys during long-distance running or due to direct injury in some sports, such as football or boxing, which may induce hematuria. [11] For instance, Polito looked for hematuria among boys after a football match and found that significant hematuria exists in urinary samples after the match. [12] Ota and et al, evaluated 109 healthy volunteers after five kilometers running for hematuria and found that 29.2%had macroscopic hematuria and 46.81% had microscopic hematuria. [13]

A study by Gerth on 51 healthy athletes after long-distance running had similar results. [14]

It is worth mentioning here that lactic acidosis generated can cause passage of erythrocytes into the urine through increased glomerular permeability. [15] The so called "foot-strike hemolysis" observed among long-distance runners is attributed to trauma to the red blood cells circulating through the sole of the runners' foot. If the hemolysis is slight, no hemoglobin is lost in the urine, as plasma haptoglobin-free hemoglobin complexes are absorbed by hepatocytes. Significant hemolysis, however, can overload available haptoglobin-binding sites and the excess hemoglobin is lost through the urine. [16]

Another mechanism for hematuria is the associated trauma to bladder and kidney. Indeed, all sports causing internal trauma to renal units, such as a football or boxing match, can cause renal vascular lesions and thus, hematuria. [16] Furthermore, it is believed that hydration status has a contributory role and athletes' dehydration during strenuous exercise could aggravate renal vascular system depression and can provoke post-exercise hematuria. [17]

Because in the majority of investigations the study population was men, it had been erroneously supposed that exercise-induced hematuria could affect only men. But, Jones et al, reported hematuria in 10.7 to 12% of women undergoing intensive physical activity for three to four hrs/day and four to five times/week. [18]

Our study did not show hematuria in any of our patients. This may be because, contrary to other contact and endurance sports, karate (Kumite) is a short duration competition with controlled strokes which possibly do not traumatize urinary system to induce hematuria. In addition, in females who have lesser aggressive tendencies than males, the karate competitions may be of low intensity. Further studies on karate induced urinary abnormalities in both genders are recommended.


1Siegel AJ, Hennekens CH, Solomon SH, Van Boeckle B. Exercise-related hematuria. Findings in a group of marathon runners. JAMA 1979; 241:391-2.
2Groop S, Stenman PH, Groop A, et al. The effect of exercise on urinary excretion of different size proteins in patients with insulin-dependent diabetes mellitus. Scand J Clin Lab Invest 1990;50:525-32.
3Poortmans JR. Exercise and renal function. Sports Med 1984;1:125-53.
4Poortmans JR. Evidence of increased glomerular permeability to proteins during exercise in healthy men. Contrib Nephrol 1988;68:136-40.
5Szygula S. Erythrocytic system under the influence of physical exercise and training, Sports Med 1990;10(3):181-97.
6Syodin B, Westing YH, Apple FS. Biochemical mechanics for oxygen free radical formation during exercise, Sport Med 1990;10: 236-54.
7Afshar R, Sanavi S, Fakharian MA, Ahmadzadeh M. The pattern of proteinuria following karate (Kumite) competitions. Nephrol Dial Transplant Plus 2008;5:376.
8Afshar R, Sanavi S, Jalali MR. Urinary sodium and potassium excretion following karate (Kumite) competition. Iranian JKD 2009;3(2): 86-8.
9Ubels FL, Van Essen GG, de Jong PE, Stegeman CA. Exercise induced macroscopic hematuria: run for a diagnosis? Nephrol Dial Transplant 1999;14:2030-1.
10Holmes FC, Hunt JJ. Renal injury in sport. Curr Sports Med Rep 2003;2(2):103-9.
11Abarbanel J, Benet AE, Lask D, Kimche D. Sports hematuria. J Urol 1990;143:887-90.
12Polito C, Andreoli S. Sport hematuria in boys: a provocative test. Pediatr Nephrol 2005;20(8): 1171-3.
13Ota M, Ozono S, Ikeda T, et al. Analysis of sports hematuria after running in summer. Nippon Hinyokika Gakkai Zasshi 2004;95(5): 705-10.
14Gerth J, Bartsch R, Hubscher J. The effect of prolonged physical exercise on renal function. Eur J Appl Physiol 2002;86:196-202.
15Bellinghierri G, Savica V, Santoro D. Renal alterations during exercise. J RenNutr 2008;18 (1):158-64.
16Jones GR, Newhouse I. Sport-related hematuria: A review. Clin J Sport Med 1997;7:119-25.
17Clement DB, Sawchuck LL. Iron status and sport performance. Sport Med 1984;1:65-74.
18Jones GR, Newhouse I. The incidence of hematuria in middle distance track running. J Appl Physiol 2001;26:336-49.