Frank M. Moses

The effect of exercise on the gastrointestinal tract

SummarySurveys 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 hat 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.Gastrointestinal bleeding is the most dramatic digestive disorder associated with exercise. While ‘runner’s anaemia’ may often represent a pseudonaemia from expanded plasma volume, runners may develop haematemesis or melaena after competitive or training events or present only with symptoms of profound iron deficiency and anemia. Many surveys have demonstrated that approximately 20% of marathon runners will convert to guaiac positivity following the race. While cases of presumed ischaemic colitis occur and anorectal sources of bleeding have been identified, by far the most frequently reported lesion of running associated bleeding has been haemorrhagic gastritis. The aetiology is felt to be ischaemic though other possibilities have not been excluded. The lesion is transient, resolves quickly with rest, and is not recognised if endoscopy is not done within 72 hours of the event. While exercise-associated intestinal bleeding is common, individual cases must be evaluated clinically. Exercise, while of obvious benefit to the general health of many, does not offer assurance against other, more mundane causes of intestinal bleeding.The study of the digestive tract during the stress of exercise is in its infancy, it is hoped that the awareness of symptoms and clinical difficulties encountered by active subjects will provoke additional study of the GI physiology of the active individual in health and disease.

Gastrointestinal bleeding during an ultramarathon

Digestive symptoms and gastrointestinal bleeding occur in endurance runners and may contribute to runners anemia. The cause is unknown, but the frequency of fecal blood loss has been reported to be 8–23% of marathon runners (1–7). Races of longer distances have not been investigated. An ultramarathon is a race that is longer than the 26.2 miles of a marathon and commonly involves distances of 30–100 or more miles and can last 24 hr or more. It differs from the marathon in duration, pace, and intrarace diet. The Old Dominion One Hundred Mile Endurance Run is held in the mountains of Virginia each June. It is open only to experienced ultrarunners who have completed a 50-mile race in less than 9 hr. This race offers a unique opportunity to study highly trained individuals undergoing a tremendous stress to not only their cardiovascular and musculoskeletal systems but also to their gastrointestinal system. The purpose of this prospective study is to determine the incidence of Hemoccult positivity occurring in association with an ultramarathon and evaluating, by means of a questionnaire, cofactors contributing to the gastrointestinal bleeding.

Surveillance Cultures to Monitor Quality of Gastrointestinal Endoscope Reprocessing

OBJECTIVES:High-level disinfection of GI endoscopes can be reliably obtained under controlled conditions with approved reprocessing methods. However, there are scant data regarding the effectiveness of these methods in clinical practice and no published methods of verification. The purpose of this study is to review retrospectively the results of environmental cultures of flexible endoscopes and to analyze the pattern of results.METHODS:Cultures of selected GI endoscopes listed as ready to use were obtained by adding 5–15 ml of trypticase soy broth or saline or 30–50 ml of sterile water to the biopsy channel of an endoscope. This wash was collected in a sterile container, plated onto blood and MacConkey agar, incubated at 37°C, and examined for growth at 24 and 48 h. Personnel trained in accordance with approved procedures performed endoscope reprocessing.RESULTS:A total of 312 surveillance cultures were performed between 1990 and 1999. Initially, three of 17 water bottles were found to be contaminated with Pseudomonas species. The bottles were sterilized daily; only sterile water was used and subsequent cultures were negative. Between 1992 and 1994, 15/129 (11.6%) cultures were positive; 14 (93%) were from duodenoscopes. From 1995 to 1997, 18/124 (14.5%) cultures were positive, but only six (33%) were from duodenoscopes. However, 10 (55.6%) positive cultures were obtained from therapeutic upper endoscopes, attributed to faulty mechanical cleaning by nonnursing personnel after emergent procedures. The reprocessing procedure was altered, with improvement. One duodenoscope was persistently culture positive and was found to have a damaged biopsy channel. There were no recognized iatrogenic infections associated with endoscopic procedures. Organisms cultured were commonly gram-negative rods.CONCLUSIONS:The use of environmental endoscope culturing is a rapid, simple, inexpensive method to monitor effectiveness of standard reprocessing procedures. Disinfection is less effective with poor mechanical cleansing, and high-titer positivity is a marker for poor cleaning technique. Standard upper and lower scopes are commonly culture negative. Duodenoscopes, because of their inherent complexity, and other scopes used in emergent conditions require particular attention. Surveillance culture results can be used to identify patterns of poor technique, to reinforce proper procedure, and to modify clinical practice. No associated clinical illness was apparent during this study.

Chronic multivitamin-mineral supplementation does not enhance physical performance.

The effects on physical performance of 90 d of supplementation with a high potency multivitamin-mineral supplement were studied in a double-blind, placebo-controlled design. Twenty-two healthy, physically active men were randomly assigned to a supplement (S) or placebo (P) group; both groups had similar physical characteristics. Performance was assessed from maximal aerobic capacity, endurance capacity, and isokinetic tests. Supplementation did not affect maximal aerobic capacity: pre and after approximately 12 wk of supplementation values for maximal oxygen consumption (48.5 +/- 1.3 vs 46.2 +/- 1.1 ml.kg-1.min-1), maximal heart rate (186 +/- 2 vs 187 +/- 2 beats.min-1) or treadmill time (19.96 +/- 0.48 vs 19.99 +/- 0.37 min) did not differ in the S group; similar findings were noted in the P group. Performance during the 90-min endurance run, as assessed from heart rates, rectal temperatures, and plasma glucose, lactate and adrenocorticotropin values, was not affected by treatment. Similarly, muscle strength and endurance were not affected. Thus, supplementation did not affect physical performance in well-nourished men who maintained their physical activity.

Running-Associated Proximal Hemorrhagic Colitis

Excerpt Gastrointestinal bleeding has been seen in long-distance runners (1), but the source of this bleeding, when not of gastric or anorectal origin, remains obscure. Intestinal ischemia has been...

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.

Hormonal responses to ingesting water or a carbohydrate beverage during a 2 h run.

Ingestion of fluids providing carbohydrate and electrolytes extends endurance times during prolonged exercise. To understand the contribution of these factors, we examined hormonal, physiologic, and metabolic responses to ingesting water (W) or a 7% glucose polymer/fructose/electrolyte solution (GPFE) in 10 men (age: 30 +/- 2 yr, VO2max: 57.4 +/- 3.2 ml.kg-1.min-1) who ran on a treadmill for 2 h at 60-65% of their VO2max. Subjects drank 200 ml of W or GPFE at 0-time and every 30 min while running (30,60, and 90 min). Changes in serum sodium, potassium, and osmolality; heart rate; plasma lactate and glucose; and serum insulin and plasma norepinephrine were similar for both fluid treatments. In contrast, changes in serum free fatty acids (FFA), plasma cortisol, and arginine vasopressin (AVP) differed across fluid treatments: with GPFE, exercise abolished the rise in plasma cortisol, and attenuated the rise in both AVP and FFA. The observed suppression of cortisol and AVP was not related to changes in any of the parameters examined, but were strongly correlated with each other. These findings suggest that adding carbohydrate and electrolytes to fluids ingested during prolonged exercise decreases activation of the hypothalamic-pituitary-adrenal axis, a potentially beneficial change. However, mobilization of FFA was also decreased. The mechanism by which they occur remains elusive.

The effect of oral decontamination with clindamycin palmitate on the incidence of bacteremia after esophageal dilation: a prospective trial

BACKGROUND Antibiotic prophylaxis to prevent bacterial endocarditis is recommended in high-risk patients undergoing esophageal dilation, a high-risk procedure. Some studies suggest that the oropharynx is the source of bacteremia. A topical antibiotic mouthwash, which reduces bacterial colonization of the oral flora, might decrease bacteremia rates and would be an attractive alternative to systemic administration of antibiotics. METHODS Adults undergoing outpatient bougienage for a benign or malignant esophageal stricture were randomized in a clinician-blinded fashion to either pre-procedure clindamycin mouthwash or no treatment. Subjects were stratified by type of dilator used. Blood cultures were obtained immediately after the first esophageal dilation and 5 minutes after the last dilation. RESULTS Fifty-nine patients were enrolled: 30 in the treatment arm and 29 in the no-treatment arm. There were 7 positive blood cultures: 5 in the treatment arm and 2 in the no-treatment arm. The identified organisms were Streptococcus viridans (2), Staphylococcus mucilaginous (2), Lactobacillus (2), and Actinomyces odontolyticus (1). Patients with bacteremia reported greater subjective difficulty with dysphagia (p = 0.01) irrespective of stricture diameter, procurement of biopsies, or dilator type. CONCLUSIONS The percentage of cases with bacteremia for all dilations performed in this manner was 12% (95% CI [5.3, 23.6]), much lower than previously cited. All organisms in this study were oral commensals. There appears to be no effect of a clindamycin mouthwash on reducing bacteremia after esophageal dilation.

Current GI Endoscope Disinfection and QA Practices

High-level disinfection (HLD) of GI endoscopes is readily achieved when published guidelines are observed. Contamination is linked to breakdowns in accepted procedure. However, there is no recognized method of verifying adequacy of endoscope reprocessing in routine practice and no data regarding current quality assurance (QA) practice. Prior reports have demonstrated a wide variation in routine clinical practice of GI endoscopy HLD. The goal of this study was to determine current practice at regional endoscopy centers with regard to endoscope cleaning and HLD, maintenance, and QA practice. An anonymous multiple-choice questionnaire was mailed to 367 SGNA members in Pennsylvania, Delaware, Virginia, Maryland, and District of Columbia and completed by 230 (63%). The majority of responders were hospital-based and 59% of the units performed over 3000 procedures per year. After use the endoscope was hand-carried or transported in a dry container (97%) to a separate cleaning room (85%) for HLD by technicians (40%). Wide variations existed in manual step procedures including use of disposable (50%) brushes and number of times channel brushed: once (21%), twice (35%), or three to five times (37%). Soaking duration in disinfectant (70% gluteraldehyde) was for ≤10 min (8%), 10–20 min (35%), 20–30 min (38%), 30–40 min (7%), and >40 min (3%). Sixty-seven percent had an active unit infection control (IC) service and 98% had a QA program. Monitoring of cleaning effectiveness was by visual inspection (50%) and culturing endoscopes (17%). Culture was done weekly (1%) and ≤ biannually (6.5%) and performed by swabing the endoscope end (5%) or rinsing the biopsy channel (8%). If culture positive, most would remove the instrument from clinical use and reevaluate the protocol and personnel for technique lapses. Two respondents were aware of a procedure-related infection. Wide practice variations were noted in manual cleaning and in soaking time during automated HLD in this community. Fewer variations were noted in cleaning personnel and training, location and methods of cleaning, and presence of IC services and QA programs. Endoscope culturing was infrequently done and positive cultures were rare. While most units claim to have ongoing QA programs, few use objective criteria to monitor effective disinfection or lapses in technique. Iatrogenic infection is uncommonly recognized following GI endoscope procedures.

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>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.