Erosive gastritis and gastrointestinal bleeding in a female runner. Prevention of the bleeding and healing of the gastritis with H2-receptor antagonists

Sports injury and illness incidence among South Korean elite athletes in the 2018 Asian Games: a single-physician prospective study of 782 athletes

Objective

The increasing incidence of sports injury among athletes calls for systemic surveillance of injuries and illnesses in this field to develop preventive measures. The patterns of injuries and illnesses that occurred among Korean athletes during the 2018 Asian Games held in Indonesia were studied.

Methods

We recorded the occurrence of all injuries and illnesses reported to the chief medical officer, coordinated with the help of an instant social messaging application in real time.

Results

A total of 782 elite athletes participated in 46 sporting events. A total of 141 (18.03%) injuries were recorded, with 121 (15.47%) athletes suffering at least one injury. Out of 141 injuries 80 (56.74%) were in male athletes and 61 (43.26%) were in female athletes. The highest number of injuries was seen among sport climbing athletes (n=10, 71.43%), followed by sepak takraw. A total of 16 (11.35%) injuries were expected to prevent athletes from participation in competition/training. Most of the injuries occurred during training (46.10%), with lower lumbar spine being the most common part injured. A total of 209 (26.72%) illnesses were reported, with at least one illness in 170 (21.73%) athletes. The incidence among female athletes (26.90%) was comparable with that of male athletes (26.90%). Maximum illness rate was reported in table tennis (100%). The most common system involved was gastrointestinal (n=93, 44.49%), followed by respiratory (n=53, 25.36%). Environmental factors were causative in 111 athletes (53.11%) and infection in 79 (37.79%). Illnesses resulted in loss of at least 1 day among 30 (14.35%) athletes.

Conclusion

Overall 15.47% of athletes suffered at least one injury and 21.73% suffered at least one illness; the incidence of injury and illness varied depending on the type of sports.

Gastrointestinal considerations related to youth sports and the young athlete

Young athletes, though often healthy, can carry a variety of symptoms that may impede their participation in sports or other activities. Typically we might think of musculoskeletal and respiratory problems primarily, however disorders of the gastrointestinal (GI) tract must also be considered. In some instances musculoskeletal complaints may bring to light activity of an underlying GI condition as is the case with inflammatory bowel disease. Gastrointestinal symptoms in the young athlete can be quite significant and a nuisance for participation. We aim to describe and discuss treatment options of a few conditions targeted specifically for your young athlete both that arise specifically from athletic participation and those GI disorders that are chronic in nature whose presence must not be neglected in the athlete.

Peripheral circulation

Blood flow (BF) increases with increasing exercise intensity in skeletal, respiratory, and cardiac muscle. In humans during maximal exercise intensities, 85% to 90% of total cardiac output is distributed to skeletal and cardiac muscle. During exercise BF increases modestly and heterogeneously to brain and decreases in gastrointestinal, reproductive, and renal tissues and shows little to no change in skin. If the duration of exercise is sufficient to increase body/core temperature, skin BF is also increased in humans. Because blood pressure changes little during exercise, changes in distribution of BF with incremental exercise result from changes in vascular conductance. These changes in distribution of BF throughout the body contribute to decreases in mixed venous oxygen content, serve to supply adequate oxygen to the active skeletal muscles, and support metabolism of other tissues while maintaining homeostasis. This review discusses the response of the peripheral circulation of humans to acute and chronic dynamic exercise and mechanisms responsible for these responses. This is accomplished in the context of leading the reader on a tour through the peripheral circulation during dynamic exercise. During this tour, we consider what is known about how each vascular bed controls BF during exercise and how these control mechanisms are modified by chronic physical activity/exercise training. The tour ends by comparing responses of the systemic circulation to those of the pulmonary circulation relative to the effects of exercise on the regional distribution of BF and mechanisms responsible for control of resistance/conductance in the systemic and pulmonary circulations.

Physiology and pathophysiology of splanchnic hypoperfusion and intestinal injury during exercise: strategies for evaluation and prevention

Physical exercise places high demands on the adaptive capacity of the human body. Strenuous physical performance increases the blood supply to active muscles, cardiopulmonary system, and skin to meet the altered demands for oxygen and nutrients. The redistribution of blood flow, necessary for such an increased blood supply to the periphery, significantly reduces blood flow to the gut, leading to hypoperfusion and gastrointestinal (GI) compromise. A compromised GI system can have a negative impact on exercise performance and subsequent postexercise recovery due to abdominal distress and impairments in the uptake of fluid, electrolytes, and nutrients. In addition, strenuous physical exercise leads to loss of epithelial integrity, which may give rise to increased intestinal permeability with bacterial translocation and inflammation. Ultimately, these effects can deteriorate postexercise recovery and disrupt exercise training routine. This review provides an overview on the recent advances in our understanding of GI physiology and pathophysiology in relation to strenuous exercise. Various approaches to determine the impact of exercise on the individual athlete's GI tract are discussed. In addition, we elaborate on several promising components that could be exploited for preventive interventions.

Review article: the pathophysiology and management of gastrointestinal symptoms during physical exercise, and the role of splanchnic blood flow

BACKGROUND

The prevalence of exercise-induced gastrointestinal (GI) symptoms has been reported up to 70%. The pathophysiology largely remains unknown.

AIM

To review the physiological and pathophysiological changes of the GI-tract during physical exercise and the management of the most common gastrointestinal symptoms.

METHODS

Search of the literature published in the English and Dutch languages using the Pubmed database to review the literature that focused on the relation between splanchnic blood flow (SBF), development of ischaemia, postischaemic endotoxinemia and motility.

RESULTS

During physical exercise, the increased activity of the sympathetic nervous system (SNS) redistributes blood flow from the splanchnic organs to the working muscles. With prolonged duration and/or intensity, the SBF may be decreased by 80% or more. Most studies point in the direction of increased SNS-activity as central driving force for reduction in SBF. A severely reduced SBF may frequently cause GI ischaemia. GI-ischaemia combined with reduced vagal activity probably triggers changes in GI-motility and GI absorption derangements. GI-symptoms during physical exercise may be prevented by lowering the exercise intensity, preventing dehydration and avoiding the ingestion of hypertonic fluids.

CONCLUSIONS

Literature on the pathophysiology of exercise-induced GI-symptoms is scarce. Increased sympathetic nervous system activity and decreased splanchnic blood flow during physical exercise seems to be the key factor in the pathogenesis of exercise-induced GI-symptoms, and this should be the target for symptom reduction.

Efeitos do exercício físico sobre o trato gastrintestinal

O impacto do exercício sobre o trato gastrintestinal (TGI), apesar de pouco investigado, é uma área de grande interesse. O exercício aeróbio intenso e de longa duração pode provocar sintomas gastrintestinais. Estes podem ser divididos em sintomas superiores (vômitos, náuseas e pirose retroesternal - azia) e inferiores (diarréia, cólica abdominal, perda de apetite, sangramento, aceleração dos movimentos intestinais e vontade de defecar). A etiologia desses sintomas durante o exercício é multifatorial e inclui a redução do fluxo sanguíneo intestinal, a liberação de hormônios gastrintestinais, o estresse mecânico sobre o TGI, a desidratação, os fatores psicológicos, a idade, o sexo, a dieta e o nível de treinamento do indivíduo. Por outro lado, o exercício de baixa intensidade tem efeito protetor sobre o TGI, principalmente com relação à predisposição a certas doenças como o câncer de cólon, a diverticulite, a colelitíase e a constipação. Diversos mecanismos são postulados para explicar os efeitos do exercício sobre o TGI, contribuindo para o desenvolvimento de estratégias terapêuticas no tratamento de indivíduos com sintomas e doenças gastrintestinais.

Proton pump inhibition prevents gastrointestinal bleeding in ultramarathon runners: a randomised, double blinded, placebo controlled study

BACKGROUND

Ultra-endurance running is emerging as a popular sport in Western industrialised countries. Gastrointestinal bleeding has been reported to be an adverse effect in these runners.

OBJECTIVE

To see if the oral administration of a proton pump inhibitor would reduce the incidence of gastrointestinal bleeding in an ultramarathon.

METHODS

In a randomised, double blinded, placebo controlled study, a prophylactic regimen of three days of an oral proton pump inhibitor (pantoprazole 20 mg) was tested in healthy athletes participating in the Spartathlon ultramarathon. The incidence of gastrointestinal bleeding was assessed by a stool guaiac test.

RESULTS

Results were obtained for 70 healthy volunteers. The data for 20 of 35 runners in the intervention group and 17 of 35 runners in the placebo group were entered into the final analysis. At the end of the ultramarathon, two subjects in the intervention group and 12 in the placebo group had positive stool guaiac tests (risk difference 0.86; 95% confidence interval 0.45 to 0.96; p = 0.001).

CONCLUSION

A short prophylactic regimen of oral proton pump inhibition can successfully decrease the incidence of gastrointestinal bleeding in participants in an ultramarathon.

Effects of ranitidine for exercise induced gastric mucosal changes and bleeding

AIM: To evaluate the effect of ranitidine on gastric mucosal changes and on GI bleeding in long distance runners.

METHODS: Twenty-four long distance runners (M: 16, F: 8, age: 18.2 ± 1.5 years) participated in this study. A symptom questionnaire, stool hemoccult test, and upper gastrointestinal (GI) endoscopy were performed on the subjects prior to the study. The subjects took oral ranitidine (150 mg, b.i.d.) for two weeks. The upper GI endoscopy and stool Hemoccult tests were repeated after the treatment.

RESULTS: Twenty-two of the 24 runners had at least one upper GI mucosal lesion before the medication. The Endoscopic improvements were seen in eleven of the 14 cases of erosive gastritis and four of the 5 cases of esophagitis. Six subjects were Heme occult positive prior to the study, but only one was positive after the medication.

CONCLUSION: Gastric mucosal lesions and GI bleeding in long distance runners seem to be associated to acid-related factors mediated by the high level of regular running. Ranitidine seems to be and effective prophylaxis to prevent gastric mucosal lesions and GI bleeding.

Exercise-associated intestinal ischemia

Ischemic bowel disease exhibits a complex spectrum of clinical presentations and in the athlete the disease may be superimposed on dehydration, hyperthermia, and exhaustion. Physicians caring for athletes should be aware of the manifestations of ischemic bowel disease and the optimum methods of diagnosis and treatment. Abdominal pain and diarrhea are typical initial symptoms of ischemia and these symptoms generally limit further damage. However, symptoms may be overridden in cases of extreme athletic competition or other significant endurance events such as combat. Athletes and coaches should be aware of the danger of ischemic bowel disease. Patients or athletes with recurrent symptoms of abdominal pain and diarrhea during exercise may be at increased risk for ischemic damage. However, no underlying anatomic abnormalities have been noted. Ischemic hemorrhagic gastritis is generally reversible and may be controlled with effective acid blockade. Ischemic colitis generally presents with pain, diarrhea, and bleeding. It is usually mild but may require volume and transfusion support, rarely progressing to need for resection or stricture. Severe presentations with intestinal infarction are rare but potentially life threatening. The athlete is usually able to ultimately resume his or her activities without restriction.

Training Room Management of Medical Conditions: Sports Gastroenterology

Gastrointestinal (GI) illnesses are common in athletes. Various causes include adverse physiologic adaptations of the gut during exercise; excess ingestion of carbohydrate drinks, alcohol, and anti-inflammatory medications; emotional stressors; exposure to pathogens in closed environments and during travel; trauma; and abdominal wall pressure overload. Unfortunately, evidence-based management of GI illnesses in athletes is limited because most studies have compared various GI illnesses between different sports, rather than comparing athletes to nonathletes. This article reviews the evidence that is available specifically relating to etiology, pathophysiology, clinical presentation, relevant differential diagnoses, acute management, and recommendations for specialist consultation of various GI illnesses in the training-room setting.

The role of gastrointestinal endoscopy in long-distance runners with gastrointestinal symptoms

BACKGROUND

Exercise-related gastrointestinal symptoms are not uncommon among athletes. The occurrence of gastrointestinal bleeding has been reported, especially in long-distance runners. We studied gastrointestinal mucosal damage, using gastrointestinal endoscopy, in competitive long-distance runners. Gastrointestinal blood loss and anaemia before and after running were also assessed.

METHODS

Sixteen competitive long-distance runners (all men; age range 16-19 years) participated in the study. All runners completed a symptom questionnaire prior to a 20 km race. Stool occult blood and haematological studies (haemoglobin, haematocrit, serum iron, total iron-binding capacity [TIBC] and ferritin) were performed before and immediately after the race. Gastrointestinal endoscopy was performed to assess macroscopic changes. Colonoscopy was also performed on the patients who had positive stool occult blood before or after the race.

RESULTS

Gastrointestinal symptoms were frequently experienced by the runners. Gastritis (n = 16), oesophagitis (n = 6) and gastric ulcer (n = 1) were found at gastroscopy. Colonoscopy was performed on four patients who had positive stool occult blood. One had multiple erosions at the splenic flexure and one had a rectal polyp. Five runners had anaemia, and all of these had at least one endoscopic lesion (three gastritis, two oesophagitis and one multiple erosion at the splenic flexure). There were significant changes in the following haematological parameters after the race: iron (decreased, P = 0.02), ferritin (decreased, P = 0.001) and TIBC (increased, P = 0.00005).

CONCLUSIONS

Gastrointestinal symptoms and gastrointestinal mucosal damage are prevalent among long-distance runners. Prior to treatment, gastrointestinal endoscopy should be considered in long-distance runners with gastrointestinal symptoms and/or anaemia.

Exercise induces gastric ischemia in healthy volunteers: a tonometry study

Heavy physical exercise may cause gastrointestinal signs and symptoms, and, although splanchnic blood flow may decrease through redistribution by more than 50%, it is unclear whether these signs and symptoms relate to gastrointestinal ischemia. In 10 healthy volunteers, we studied the effect of exercise on gastric mucosal perfusion adequacy using air tonometry. Two relatively short (10 min) exercise stages were conducted on a cycle ergometer, aiming for 80 and 100% of maximum heart rate, respectively. The intragastric-arterial PCO(2) gradient (Delta PCO(2)) was elevated by 1.1 +/- 1.0 kPa over baseline values (-0.1 +/- 0.3 kPa) only after maximal exercise (P < 0.001). Delta PCO(2) positively correlated with the arterial lactate level taken as an index of exercise intensity (Spearman's rank test: r = 0.76, P < 0.0001). By bilinear regression analysis, a lactate level of 12 mmol/l, above which a sharp rise in the Delta PCO(2) occurred, was calculated. We conclude that, in healthy volunteers with normal splanchnic vasculature, gastric ischemia may develop during maximal exercise as judged from intragastric PCO(2) tonometry.

Peptic ulcer disease in children

A peptic ulcer in a child looks the same as it does in an adult, and many of the aetiologies of peptic ulcer disease in children are similar to those in adults. However, there are many differences between children and adults, especially in the areas of clinical presentation, the prevalences of different types of ulcer disease, and the prevalence of complications of ulcer disease. Therefore the approach to diagnosis and management in children is often at variance with that in adults. One important example is the approach to suspected Helicobacter pylori (H. pylori) disease in children, in which consensus groups have advised a considerably different approach in children. While the chapter deals with the full range of peptic ulcer disease in children, the focus is on those aspects in which there are differences between adults and children.

Aetiology of running-related gastrointestinal dysfunction. How far is the finishing line?

30 to 65% of long distance runners experience gastrointestinal (GI) symptoms related to exercise. Several hypotheses have been postulated; however, the aetiology and pathophysiology are far from clear. The mechanical effect of running on the viscera must be involved in the development of GI symptoms in this sport. Reduction of splanchnic blood flow due to visceral vasoconstriction is another widely supported theory; nevertheless, it does not explain many of the clinical findings. Examination of the GI tract during exercise is a difficult task, and measurements of both orocaecal and whole-gut transit time have shown equivocal results. GI hormones, and especially prostaglandins, may be of crucial importance for the production of symptoms. Intestinal absorption, secretion and permeability may also be altered during exercise, provoking intestinal dysfunction. Factors such as stress, diet, dehydration, infections and other factors need to be analysed in order to present a global view of the hypotheses regarding the aetiology of this common and often overlooked problem.

Monoclonal antibodies for exercise-induced fecal blood detection--comparison with Hemofec

The purpose of this investigation was to determine the incidence of fecal occult blood in marathoners using an immunochemical technique (OC-Hemodia). Five stool specimens (2 pre- and 3 postrace) were collected from 24 male runners (mean age 41.4 +/- 9.3 yrs) and analysed for fecal occult blood using the OC-Hemodia test. The results were also compared with a qualitative test (Hemofec) in 12 subjects who were randomly selected from the overall group of 24 runners. With the immunochemical technique, the results evidenced the presence of fecal occult blood in 8 subjects in the first postrace stool specimens. Four of these 8 subjects also tested positive in the second postrace sample, whereas in the third postrace sample only one of them tested positive. With the qualitative test, fecal blood was demonstrated in 10 runners in the first postrace sample. Eight of them tested positive in the second sample, whereas only 5 tested positive in the third sample. The immunochemical technique is recommended for fecal occult blood detection in marathoners.

Effect of cimetidine on marathon-associated gastrointestinal symptoms and bleeding

Occult gastrointestinal bleeding occurs in 8-30% of marathon runners. We hypothesized that cimetidine would decrease bleeding by reducing acid-mediated injury and conducted a blinded, placebo-controlled prospective trial to determine the impact of cimetidine on gastrointestinal symptoms and bleeding during a marathon. Thirty participants in the 1989 Marine Corps or New York City marathons completed pre- and postrace: (1) a questionnaire evaluating demographic, medication usage, training history, and gastrointestinal symptoms; (2) three consecutive stool Hemoccult (HO) cards; and (3) a stool Hemoquant (HQ). Fourteen runners (CR) took 800 mg of cimetidine by mouth 2 hr before the start and 16 runners (PR) took placebo. Three subjects were HO+ prerace and were not analyzed. Three subjects failed to take drug as directed and were analyzed as PR. Five of 14 PR and two of 13 CR were HO+ postrace (P greater than 0.05). Prerace HQ values (PR: 1.49 +/- 0.6 and CR: 0.60 +/- 0.1 mg hemoglobin/g stool) were not significantly different from postrace HQ values (PR: 0.73 +/- 0.2 and CR: 0.86 +/- 0.2 mg Hgb/g stool). Despite postrace HO+ conversion, no individual postrace HQ became abnormal. The frequency of gastrointestinal symptoms was similar for CR and PR, as well as HO- and HO+ individuals. Cimetidine did not significantly affect occult gastrointestinal bleeding as measured by HO or HQ results. This suggests that marathon-associated gastrointestinal symptoms and bleeding may be due to lesions other than acid-mediated disease or hemorrhagic gastritis.

Occult Gastrointestinal Bleeding in Endurance Cyclists

In brief Gastrointestinal (GI) bleeding has been well documented in long-distance runners but not in cyclists. The disorder is thought to occur in other strenuous endurance sports as well. The purpose of the present study was to identify the incidence of occult GI bleeding in a large group of endurance cyclists who participated in the 7-day Bike Ride Across Nebraska. Of 500 participants, 35 submitted 163 stool specimens during the first 6 days of the ride; only two specimens, from two riders (1.2%), were positive for occult blood. GI bleeding deserves further research to determine the incidence and cause or causes of this intriguing problem among athletes who engage in strenuous sports.

Cimetidine reduces running-associated gastrointestinal bleeding. A prospective observation

A prospective observational study was undertaken to compare the effect of cimetidine usage immediately before and during a 100-mile running race on the frequency of detectable gastrointestinal bleeding and to relate these data to the frequency and intensity of gastrointestinal symptoms and to training data collected from pre- and postrace questionnaires. Nine of 25 runners in the 1989 Old Dominion 100-mile Endurance Race took 800 mg of cimetidine 1 hr before the start and at 50 miles. Sixteen other runners acted as controls and were not different in age, gender, or training data. All runners also submitted three stool specimens from the week before the race and from the first three bowel movements after the race on standard Hemoccult cards. All runners were Hemoccult negative before the race. One of the 9 (11%) cimetidine runners and 14 of the 16 (87.5%) control runners were Hemoccult positive afterwards (P less than or equal to 0.05). Nausea and vomiting were less in those runners taking cimetidine (P less than or equal to 0.05). There was no difference in the race performance as related to the ability to finish or in the number of miles run during the race. This study may help to define the etiology of this common gastrointestinal bleeding in these ultradistance runners and may be useful in preventing some of the symptoms associated with long-distance running.

The effect of exercise on the gastrointestinal tract

Surveys of athletes, primarily runners, have shown that digestive disorders are common, associated both with training and racing. Women, in particular, seem to suffer most commonly. Nearly half have loose stools and nausea and vomiting occur frequently after hard runs. Diarrhoea, incontinence and rectal bleeding occur with surprising frequency. Runners may use medications prophylactically to minimise some of these symptoms. Upper digestive symptoms seem to occur more commonly in multisport events such as triathlons or enduro. The published literature is difficult to analyse and the basic intestinal physiology not well studied. Most gastroenterologists are accustomed to evaluating the fasting patient at rest and exercise physiologists are seldom experienced with digestive techniques. Digestive symptoms occurring with exercise referable to the oesophagus include chest pain, gastro-oesophageal reflux symptoms, or symptoms related to alterations in motility. While little is known of the oesophageal physiology during exercise, it is believed that only minimal changes occur in most subjects. Gastro-oesophageal reflux occurs more frequently with exercise than at rest and may produce symptoms of chest pain suggestive of ischaemic disease. Acid exposure may be reduced by pretreatment with histamine H2-receptor antagonists. Oesophageal symptoms, though common, are rarely disabling to the athlete, and the clinical importance lies in confusion with ischaemic disease. Cases of acute gastric stasis following running have been reported and gastric physiology during exercise, particularly bicycling, has been more actively investigated. Gastric emptying during exercise is subject to a number of factors including calorie count, meal osmolality, meal temperature and exercise conditions. However, it is generally accepted that light exercise accelerates liquid emptying, vigorous exercise delays solid emptying and has little effect upon liquid emptying until near exhaustion. Gastric acid secretion probably changes little with exercise although some have postulated that ulcer patients may increase secretion with exercise. Some exercise-associated digestive symptoms, such as diarrhoea and abdominal pain, have been attributed to changes in intestine function. Small bowel transit is delayed by exercise when measured by breath hydrogen oral caecal transit times and motility may be reduced as well. Intestinal absorption during exercise has not been well evaluated but probably changes little in ordinary circumstances. Passive absorption of water, electrolytes and xylose are not affected by submaximal effort. Colonic transit and function is even more difficult to evaluate and published results have been conflicting. However, it is likely that many of the lower digestive complaints of runners such as diarrhoea and lower abdominal cramps are due to direct effects of exercise upon the colon.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrointestinal bleeding during an ultramarathon

A prospective study was undertaken to determine the frequency of detectable gastrointestinal bleeding in participants of a 100-mile running race. Pre- and postrace questionnaires were utilized to determine training data, gastrointestinal symptoms, diet, and the use of medications during training and during the race, prior known gastrointestinal disease, and 100-mile race experience. Three prerace and the first three postrace stools were sampled for blood using the standard Hemoccult method in 35 runners: 85% of the participants who were Hemoccult negative before the race converted to positive in their postrace samples. Runners with the postrace Hemoccult-positive stools had more frequent and intense nausea, diarrhea, abdominal cramping, and bloating (P less than 0.05) during the race. Lower gastrointestinal symptoms correlated with Hemoccult positivity (P less than 0.05), whereas upper gastrointestinal symptoms did not. The majority of participants showed evidence of gastrointestinal bleeding after the race. Digestive symptoms are common and lower gastrointestinal symptoms correlate with gastrointestinal bleeding.

Gastrointestinal Bleeding in Athletes

In brief: Gastrointestinal (GI) bleeding is a troubling yet intriguing complication of distance running. This clinical overview traces our evolving understanding of the scope and importance of GI bleeding in runners and other athletes, and discusses the diverse causes, sites, and implications of exercise-related GI bleeding. It concludes with practical tips to prevent or mitigate this problem, including gradual conditioning, avoidance of prerace aspirin intake, and when indicated, therapy with antacids, H2 blockers, or iron.

Causes of iron deficiency in adolescent athletes

Seventy-two high school cross-country runners were studied during the running session for possible etiologic factors associated with iron deficiency, which was defined as a serum ferritin level less than or equal to 12 ng/ml and a transferrin saturation of less than or equal to 16% occurring simultaneously. Iron deficiency was observed during the running season in 34% of female cross-country runners, compared with 8% of male runners. Increased iron losses through gastrointestinal bleeding occurred in 9 of 20 female runners; 7 of these 9 had iron deficiency. Dietary iron intake was low in both iron-deficient and iron-sufficient female runners, but dietary instruction did not increase iron intake significantly. Iron deficiency could not be prevented in 35% of the female runners treated with 60 mg of elemental iron daily, but adequate treatment was achieved with 180 mg. Iron losses in urine, sweat, and plasma were small and did not appear to be increased in iron-deficient runners. These findings indicate that female cross-country runners have a high incidence of iron deficiency that is associated with initially decreased iron stores and gastrointestinal bleeding.