Risk factors for exercise-related acute cardiac events. A case-control study.

BACKGROUND: In spite of the benefits of physical activity, exercise may provoke acute cardiac events in susceptible individuals. Understanding risk factors of exercise-related acute cardiac events may identify opportunities for prevention. METHODS: A case-control study was conducted to examine determinants of acute cardiac events in athletes. The cases were athletes who suffered an acute cardiac event during or shortly after vigorous exercise. Athletes who visited a hospital because of a minor sports injury were selected as controls. Information on cardiovascular disease, family history of cardiovascular disease, cardiovascular symptoms and other potential risk factors was collected through questionnaires. RESULTS: 57 cases (mean age 41.8 years, range 11-73) and 57 controls (mean age 40.9 years, range 13-68) were included in the study. Athletes with a history of cardiovascular disease were at a markedly increased risk for cardiac events during exercise (OR = 32; 95% CI 7.4 to 143). Smoking (OR 5.9; 95% CI 1.9 to 18), fatigue (OR = 12; 95% CI 1.2 to 118) and flu-like symptoms (OR 13; 95% CI 1.4 to 131) in the month preceding the event were related to acute cardiac events in athletes. CONCLUSIONS: Prior cardiovascular disease, smoking, and a recent episode of fatigue or flu-like symptoms are associated with an increased risk of exercise-related acute cardiac events. Athletes and physicians should pay careful attention when these factors exist or occur.

The first 20 years of bradypacing in the Netherlands - with special reference to organisational structures.

In 1958, Arne Larson was the first patient to undergo an implantation of a completely internal pacemaker. Four years after this successful implantation by Senning and Elmquist in Sweden, Brom implanted the first internal system in a Dutch patient in Leiden.The pioneering work and the early history of bradypacing in the Netherlands until 1982 are described. This article covers the involvement of different specialists, organisations and some of the technical problems encountered during the rapid increase in the number of implantations and the establishment of specialist centres. The important role of Thalen and Rodrigo, as founding fathers of cardiac pacing in the Netherlands, is also highlighted. (Neth Heart J 2008;16(Suppl1):S5-S8.).

Endothelial markers in chronic heart failure: training normalizes exercise-induced vWF release.

BACKGROUND: Chronic heart failure (CHF) is characterized by endothelial dysfunction. Vascular endothelium is important for control of haemostasis and vasoregulation. The aim of the present study was to investigate plasma levels of several endothelial markers and the exercise-induced changes on these plasma levels in CHF patients. Subsequently, the effect of a 6-month training programme on these markers is described. MATERIALS AND METHODS: Twenty-nine male CHF patients (NYHA II/III, age 60 +/- 8 year, body mass index 26.7 +/- 2.3 kg m(-2), left ventricular ejection fraction 26.3-7.2%; mean +/- SD) participated. Patients were randomly assigned to a training or control group. Training (26 weeks; combined strength and endurance exercises) was four sessions/week: two sessions supervised and two sessions at home. Before and after intervention, anthropometry, endothelial markers (haemostasis and vasoregulation), maximal workload and peak oxygen uptake were assessed. RESULTS: Physical training positively affected maximal workload. Plasma levels of endothelial markers were not affected by physical training and not related to exercise tolerance. After training, stimulated (maximal exercise) plasma von Willebrand Factor (vWF) release was present, whereas at baseline this release was absent. CONCLUSION: Physical training led to normalization of the stimulated plasma vWF release. Plasma levels of other endothelial markers were not affected by physical training either at rest or under stimulated (maximal exercise) conditions.

[Guideline 'Chronic heart failure']. / Richtlijn 'Chronisch hartfalen'.

A new Dutch clinical practice guideline has been developed for the diagnosis, treatment and supportive care of patients with chronic heart failure. This has been formulated by a multidisciplinary working group, set up by the Netherlands Heart Foundation and the Netherlands Society of Cardiology, in cooperation with the Dutch Institute for Healthcare Improvement. Heart failure is defined as: 'a complex of complaints and symptoms resulting from an inadequate pumping function of the heart'. Indications for heart failure are dyspnoea on exertion, reduced exertion tolerance and oedema. By using data from the medical history, case history, physical examination and simple additional tests (laboratory tests, ECG, chest X-ray photos) it is possible to demonstrate or exclude heart failure in clear-cut cases. Doppler ultrasonography should be performed in all patients where heart failure is suspected but cannot be clearly demonstrated. The initial treatment for patients with heart failure with reduced systolic LV function generally consists of the administration of a thiazide or loop diuretic together with an angiotensin-converting enzyme inhibitor and a beta-blocker, to which digoxin and/or spironolactone may be added. For very old patients extra attention should be given to the comorbidity and the medication and dosing scheme should be as simple as possible. The worse the cardiac function, the more the salt and fluid intake should be limited and the more strictly the weight should be monitored.

Does physical training increase insulin sensitivity in chronic heart failure patients?

To determine the effect of training on insulin sensitivity (IS) and how this relates to peak V(.)O(2) (peak oxygen uptake) in CHF (chronic heart failure), 77 CHF patients (New York Heart Association class, II/III; men/women, 59/18; age, 60+/-9 years; body mass index, 26.7+/-3.9 kg/m(2); left ventricular ejection fraction, 26.9+/-8.1%; expressed as means+/-S.D.) participated in the study. Patients were randomly assigned to a training or control group (TrG or CG respectively). Sixty-one patients completed the study. Patients participated in training (combined strength and endurance exercises) four times per week, two times supervised and two times at home. Before and after intervention, anthropometry, IS (euglycaemic hyperinsulinaemic clamp) and peak V(.)O(2) (incremental cycle ergometry) were assessed. Intervention did not affect IS significantly, even though IS increased by 20% in TrG and 11% in CG (not significant). Peak V(.)O(2) increased as a result of training (6% increase in TrG; 2% decrease in CG; P <0.05). In both groups (TrG and CG), the change in IS correlated positively with the change in peak V(.)O(2) ( r =0.30, P <0.05). Training resulted in an increase in peak V(.)O(2), but not in IS. Whether physical training actually increases IS in CHF patients remains unclear.

Determinants of insulin sensitivity in chronic heart failure.

OBJECTIVE: To describe the determinants of insulin sensitivity (IS) in chronic heart failure (CHF), we created a model in which the influence of lifestyle factors and etiology of heart failure on IS were incorporated concomitantly with age, left ventricular ejection fraction (LVEF) and parameters of body composition. DESIGN: Observational cohort study. SETTING: Outpatient clinic for chronic heart failure. PATIENTS: Fifty-seven male CHF patients [NYHA class II-III, age 61+/-9 years, body mass index (BMI) 26.9+/-3.3 kg/m2 (mean+/-S.D.)]. INTERVENTIONS: Euglycemic hyperinsulinemic clamp, cycle ergometry, anthropometric measurements, LVEF and a physical activity questionnaire. MAIN OUTCOME MEASURES: A model explaining the variance of IS in CHF. RESULTS: IS was 18.2+/-8.6 microg.kg(-1).min(-1).mU(-1).l(-1), fasting insulin level was 15.9+/-11.0 mU/l and fasting glucose level was 5.5+/-0.6 mmol/l. Peak VO2 was 19.1+/-4.9 ml.kg(-1).min(-1) and LVEF 26.2+/-7.1%. IS was inversely associated with fasting insulin concentration (r=-0.50, P<0.001) and BMI (r=-0.54, P<0.001). After controlling for BMI, IS also revealed a correlation with age (r=-0.36, P<0.01). The model explained 60% of variance in IS: BMI contributed 20%, smoking 17%, age 17% and physical activity in daily life (DPA) 16% (all P<0.05) to the variance of IS, whereas LVEF (9%) and etiology of heart failure (8%) contributed moderately. CONCLUSIONS: In CHF patients, IS is for a major part predicted by BMI, smoking, age, daily physical activity, LVEF and etiology of heart failure.

Recognising vascular causes of leg complaints in endurance athletes. Part 2: the value of patient history, physical examination, cycling exercise test and echo-Doppler examination.

UNLABELLED: Leg complaints at maximal exercise in endurance athletes may have many causes, including arterial flow limitations in the iliac arteries. Such flow limitations can evolve into serious health problems due to increasing intravascular obstruction or even complete obstruction as a result of dissection or thrombosis. Early detection is therefore of clinical importance, but conventional diagnostic tools often prove inadequate. In the current study simple sports-specific tests are examined for their diagnostic power. Test variables derived from patient history, physical examination, cycling exercise testing followed by arterial pressure measurements at the ankle, and echo-Doppler examination with provocative manoeuvres were tested in 92 symptomatic legs (80 patients). A validated clinical classification acted as a reference. Several test variables proved useful. However, no single test variable combined a high sensitivity with a high specificity. Multivariate testing resulted in the correct classification of 91 % of patients, reaching a sensitivity of 0.90 and specificity of 0.93 (kappa 0.76). Four patients wrongly classified as non-vascular suffered from kinking in the common iliac artery that could not be visualised using the diagnostic tools currently available in this study. IN CONCLUSION: simple sports-specific tests accurately diagnose iliac artery obstruction in endurance athletes.

Recognising vascular causes of leg complaints in endurance athletes. Part 1: validation of a decision algorithm.

Flow limitations in the iliac arteries of endurance athletes during exercise were previously ascribed solely to intravascular lesions. We postulate that functional kinking of the arteries can also result in flow limitations. However, the diagnostic tools in routine practice are not effective in diagnosing such flow limitations in a substantial proportion of athletes, mainly because these diagnostic tools do not measure in the provocative situations. Ninety-two symptomatic legs in 80 endurance athletes were examined with newly developed, sports-specific vascular tests. Thirty-five asymptomatic cyclists matched for working capacity served as the control subjects. Legs were classified as vascular or non-vascular following a decision algorithm, based upon the results of these diagnostic tests, excluding orthopaedic causes by the effects of specific treatment. Independently of this clinical classification, an alternative method was applied to find stable characteristics in the total patient group using factor analysis. This characterisation was based on scores on 14 test variables deriving from diagnostic tests that were not used in the decision algorithm, thus avoiding dependency between the clinical categorisation and the statistical categorisation. The hypothesis was that these characteristics were sufficiently sensitive to classify patients with vascular and non-vascular complaints. If so, these characteristics should correspond with the one derived from the decision algorithm. Following the decision algorithm, 58 legs (63%) were classified as vascular, 29 (32%) as non-vascular and 5 (5%) as inconclusive. The latter were considered non-vascular. In a substantial proportion of the vascular patients, kinking of the iliac arteries was identified as the major cause of flow limitation. The characteristics derived from factor analysis proved to classify 87% in agreement with the decision algorithm (kappa 0.56). The agreement is sufficient for validation of the clinical classification. The algorithm can therefore be applied in clinical situations to diagnose endurance athletes with flow limitations due to both intravascular lesions and kinking of the arteries.

Reproducibility of ultrasound blood flow measurement of the superior mesenteric artery before and after exercise.

This study examines the reproducibility of gastro-intestinal blood flow measurements in the superior mesenteric artery (SMA) both before and immediately after exercise with Doppler ultrasound measurements. Twelve well-trained males (mean +/- SD: age 25.9 +/- 3.8 yr; VO2max 4.8 +/- 0.91 x min(-1)) were measured twice (trial 1 and 2) with a 1 week interval before and immediately after 1 hr cycling at 70% VO2max. Duplex scanning was performed with the athletes in supine position immediately after transition from a chair (before exercise) or bicycle (after exercise). The variability of three measurements before exercise was studied within both trials (short-term reproducibility) and the mean pre-exercise values were compared between the trials (long-term reproducibility). In addition, post-exercise measurements were compared in the same way. Reproducibility was tested using the coefficient of variation and Cronbach's alpha. Mean pre-exercise blood flow was 424 +/- 66 ml/min (n = 12) in trial 1 and 375 +/- 38 ml/min (n = 11) in trial 2. Immediately after exercise blood flow had decreased by 49% to 214 +/- 36 ml/min (p <0.01) in trial 1 and by 38% to 234 +/- 36 ml/min (p < 0.01) in trial 2. Blood flow before and after exercise was not significantly different between trials (paired t-test) and therefore reproducible at the group level. Before exercise a good to fair reproducibility was observed both at the short-term (Cronbach's alpha: 0.88 in trial 1, 0.73 in trial 2, n = 11), and at the long-term (alpha = 0.80, n= 11). In contrast, long-term reproducibility immediately after exercise was poor (alpha = -0.99, n = 8 and alpha = 0.36, n = 7 after the first and second cycling period, respectively). In conclusion, duplex scanning of SMA after a sitting-supine transition in well-trained subjects is not a reproducible method at the individual level for intestinal blood flow measurements immediately after exercise.

Aging, physical conditioning, and exercise-induced changes in hemostatic factors and reaction products.

The influence of age on training-induced changes in resting and stimulated hemostatic potential was studied in three age categories (Cat I-III; 20-30 yr, 35-45 yr, and 50-60 yr, respectively) of sedentary men before and after 12 wk of training. Coagulation, fibrinolytic activity, and activation markers (reflecting fibrin formation and degradation) were determined. Physical conditioning resulted in a more pronounced increase in von Willebrand factor (vWF) and factor VIII clotting activity (FVIII:c) in Cat I and II and a more pronounced shortening of the activated partial thromboplastin time in all categories at maximal exertion and during recovery. Enhanced increases in tissue-type plasminogen activator (t-PA) antigen and activity and single-chain (sc) urokinase-type plasminogen activator (u-PA) at maximal exercise and 5 min of recovery were observed in all age groups after training. The effects on FVIII:c, vWF, and scu-PA were most pronounced in the youngest age group (Cat I). Increases in the marker of thrombin generation were highest in Cat III; no effect was seen on thrombin-antithrombin complex, plasmin-antiplasmin complex, and D-dimer in any of the age groups. We concluded that training enhances both coagulation and fibrinolytic potential during strenuous exercise. The effect on FVIII/vWF and t-PA/u-PA is most pronounced in younger individuals, whereas thrombin formation is most pronounced in older individuals.

Cardiopulmonary exercise parameters in relation to all-cause mortality in patients with chronic heart failure.

In this study we analysed the all-cause mortality over a period of maximal 6 years in 60 male patients (age: 63.4+/-8.3 years, mean+/-S.D.), suffering from chronic heart failure with resting left ventricular ejection fraction and E/O2 slope as independent factors. We assessed functional NYHA class (II: n=36, III: n=24), radionuclide left ventricular ejection fraction (29.2+/-10.4%) and peak values of heart rate, O2, CO2, E, anaerobic threshold and exercise duration with an incremental work load test on the treadmill. O2 relative to E was based on the individual slopes of the regression of O2 on E during the first 6 min of exercise. These slopes with other exercise-related variables and factors such as etiology, medication, and NYHA class were analysed with a Cox's Regression Method. A survival time analysis (Kaplan-Meier survival curve) was done to establish the influence of E/O2 slope and left ventricular ejection fraction (both split into above and below median values), as well as their interaction, on survival. From all investigated exercise-related variables. E/O2 slope is the most powerful variable regarding prediction of all-cause mortality in our group of chronic heart failure patients. Concerning risk stratification, the subgroup (n=18) with a relatively high left ventricular ejection fraction (>28%) and flat E/O2 slope (<27.6) had most survivors (77.8%) after about 3 years, while the subgroup (n=12) with a relatively high left ventricular ejection fraction (>28%), but a steep E/O2 slope (>27.6) had least survivors (33.3%). This difference in percentage is highly significant (P=0.0025). The fact that E/O2 slope and left ventricular ejection fraction show comparable main and interaction effects between measures of exercise tolerance (e.g., anaerobic threshold, peak O2, exercise duration) on the one hand, and all-cause mortality on the other, suggests the existence of common sources of variance. Based on our analysis, it is unlikely that effects on all-cause mortality are mediated through phenomena related to exercise tolerance. Therefore, we hypothesize that the effects on exercise tolerance and all-cause mortality both depend on common factors, which cause both cardiac and peripheral organ (c.q. muscular) dysfunctions. Moreover, this study clearly shows that E/O2 slope during incremental exercise is an important prognostic marker for risk stratification in chronic heart failure patients, NYHA class II and III.

Correlated neurocardiologic and fitness changes in athletes interrupting training.

PURPOSE: We studied nine male Dutch top marathon skaters during a 1-month interruption of their training schedules after their last contest in the winter to investigate a possible decline in baroreflex sensitivity. METHODS: Before and after this period, a maximal exercise test was done, and at days 0, 4, 7, 14, and 28 neurocardiologic measurement sessions--heart rate and noninvasive baroreflex sensitivity, recumbent and tilt--were performed. RESULTS: Interruption of training resulted in a significant and relevant decrease in the maximal oxygen uptake (from 65.7 +/- 5.8 to 61.6 +/- 4.7 mL O2 x kg(-1) x min(-1); P = 0.03), most likely associated with decreased competitive possibilities. Resting heart rate modestly increased (from 54.6 +/- 7.2 to 58.8 +/- 7.5 bpm), however, not significantly. Heart rate during 60 degrees tilt increased considerably (from 70.1 +/- 6.1 to 80.1 +/- 9.1 bpm; P = 0.01), possibly due to a decrease in blood volume and an increase in cardiopulmonary baroreflex gain. Arterial baroreflex sensitivity decreased significantly in the recumbent (from 13.3 +/- 5.4 to 9.8 +/- 3.8 ms x mm Hg(-1), P = 0.04), but not in the 60 degrees tilt position (from 6.7 +/- 2.0 to 6.0 +/- 2.5 ms x mm Hg(-1)). The relative decrease in baroreflex sensitivity and maximal oxygen uptake correlated significantly (r = 0.71, P = 0.02). CONCLUSIONS: In summary, our data show that correlated detrimental changes in fitness and baroreflex sensitivity are measurable in these athletes after a month of interruption of training.

The effect of a sports drink on gastroesophageal reflux during a run-bike-run test.

The effects of different modes of prolonged exercise and different drinks on gastroesophageal reflux and reflux-related symptoms were examined. In a cross-over design seven male triathletes performed two tests at one week intervals (50 min periods of alternately running, cycling and running at 70-75% VO2max), with supplementation of either a conventional sports drink (7% carbohydrates) or tap water. Gastroesophageal reflux (percentage time and number of periods esophageal pH < 4) was measured with an ambulant pH system before, during and after exercise. Percentage reflux time (+/- SEM) during running, cycling, running and recovery was 24.0 +/- 4.6, 8.2 +/- 4.8, 17.6 +/- 8.4 and 11.8 +/- 4.0 with carbohydrates and 7.4 +/- 2.9, 0 +/- 0, 2.4 +/- 1.4 and 0.2 +/- 0.2 with water, respectively. Reflux lasted longer during exercise as compared to the rest situation (5.6 + 1.4%), especially with carbohydrates, and lasted longer with carbohydrates than with water (P < 0.05; Wilcoxon signed rank test). In general, reflux lasted longer during running than during cycling (P < 0.05). Data on the number of reflux periods are concordant to these results. Chest pain was reported by one subject during running with carbohydrates. Heartburn during running was reported by two subjects with water and by one with carbohydrates. In conclusion, physical exercise increases gastroesophageal reflux, dependent on the mode of exercise and beverage used.

Gastrointestinal mucosal integrity after prolonged exercise with fluid supplementation.

PURPOSE: Studies on the effect of exercise on gastrointestinal (GI) mucosal integrity have been limited to occult-blood tests, which were often nonspecific for human blood. The aim of our study was to investigate more aspects of this integrity. METHODS: We examined the effect of prolonged exercise and carbohydrate (CHO) supplementation on mucosal integrity in 22 male triathletes by measuring fecal lysozyme, alpha1-antitrypsin, and occult-blood loss, which was examined by two tests specific for human blood (Colon-Albumin and Monohaem test). Exercise consisted of two 150-min tests (alternately running, cycling, and running at 70-75% VO2max), either with a 7.0% CHO drink or water (W). Furthermore, GI symptoms during exercise were registered by questionnaire. RESULTS: Three subjects showed human albumin only in the first stool after exercise: twice with W and once with CHO. However, human hemoglobin (Hb) could not be detected in these samples. Four other subjects showed an elevated lysozyme concentration after exercise with CHO but not with W. Elevated alpha1-antitrypsin values were found in three of seven specimens in which either positive albumin tests and/or an elevated lysozyme concentration were demonstrated. Twenty-one subjects (95%) reported one or more GI symptoms during exercise. Incidence rates of different GI symptoms varied from 5 to 68%. Most symptoms were more frequent and lasted longer during running than during cycling but did not differ significantly between supplements and were not related to any mucosal integrity parameter. CONCLUSIONS: GI blood loss during exercise is of no clinical importance, at least in our study design with a group of well-trained male subjects who consumed a relatively high amount of fluid (up to 2.3 L). Nevertheless, an increased alpha1-antitrypsin and lysozyme concentration may indicate a transient local mucosal damage with an inflammatory response.

AV blocking due to asynchronous vagal stimulation in rats.

The parasympathetic nervous system innervates the heart through two cervical vagal branches. The right vagal branch mainly influences the heart rate by the modulation of the rhythmogenesis of the sinoatrial node. The left branch predominantly influences the conduction properties of the atrioventricular (AV) node. We investigated the effect of asynchronous stimulation by the vagal nerves on the occurrence of irregularities in heart rate. In rats, the vagal nerves were isolated and cut. Different vagal stimulation patterns (continuous, pulsed) were applied. The heart was beating spontaneously under continuous vagal stimulation. In case of pulsed vagal stimulation, the atria were paced at different rates. Asynchronicity was induced by delaying the right stimulus with respect to the left stimulus (early right) or the left stimulus with respect to the right stimulus (early left). The value of the fraction of deviated R-R or P-Q intervals in the distribution in the histogram was used to characterize irregularities during a stimulation protocol (duration in case of continuous stimulation: 20 s; pulsed stimulation: 120 s). Under both stimulation patterns (continuous or pulsed), we found that early left vagal stimulation introduced a much larger fraction of deviated intervals in the R-R or P-Q histogram (in R-R: 29.1 +/- 4.9%; in P-Q: 12.90 +/- 1.95%) than early right vagal stimulation (in R-R: 7.4 +/- 2.0%; in P-Q: 1. 05 +/- 0.50%) or synchronous stimulation (in R-R: 8.2 +/- 3.6%; in P-Q: 2.15 +/- 0.75%). We conclude that early stimulation by the left vagal nerve can introduce irregularities in heart rate, mainly due to different degrees of AV nodal blockade.

Baseline and previous physical activity in relation to mortality in elderly men: the Zutphen Elderly Study.

Understanding the effect of changes in physical activity on mortality risk may help researchers clarify intervention strategies. This study investigated associations of physical activity at baseline and 5 years previously with all-cause mortality risk in a cohort of 472 elderly Dutch men. Relative risks were estimated for relations between mortality in 1990-1995 and physical activity levels in 1990 and 1985. Adjustments were made for baseline age, chronic diseases, functional status, and lifestyle factors. In contrast to previous levels of physical activity (adjusted p-trend = 0.39), baseline total time spent in physical activity was inversely associated with mortality risk (p-trend = 0.004; for the most active tertile vs. the least active, relative risk = 0.44; 95% confidence interval: 0.25, 0.80). No consistent associations were observed after fractionating total physical activity into activities of differing intensity or into four different types of activity. Relative to maintaining a physically active lifestyle (i.e., walking or bicycling for 20 minutes at least three times per week) in both survey years, a gradient of increasing risk was observed from adopting an active lifestyle to becoming sedentary to remaining sedentary (p-trend = 0.004). Recent levels of physical activity were more important for mortality risk among elderly men than activity 5 years previously. Becoming or remaining sedentary was significantly associated with increased mortality risk in comparison with remaining physically active.

The effect of omeprazole on gastro-oesophageal reflux and symptoms during strenuous exercise.

BACKGROUND: Strenuous exercise exacerbates gastro-oesophageal reflux and symptoms and this may be diminished by antisecretory medication with omeprazole. METHODS: Fourteen well-trained athletes (13 men, one woman), who indicated suffering from either heartburn, regurgitation or chest pain during competition running, performed two experimental trials at 2-week intervals using a randomized, double-blind, placebo-controlled crossover design. During the 6 days preceding the trial and on the trial day itself either 20 mg of omeprazole or a placebo was administered. Two hours after a low-fat breakfast and 1 h after the last study dose, the trial started with five successive 50-min periods: rest, three running periods on a treadmill, and recovery. Reflux (percentage time and number of periods oesophageal pH <4) was measured with an ambulant pH system during these periods. RESULTS: Compared to rest, reflux lasted significantly longer and occurred more frequently during the first running period, irrespective of the intervention, whereas during the second running period this effect was only observed with the placebo. Reflux occurred for longer and more frequently with the placebo than with omeprazole, but this was significant during the first two running periods only. Seven subjects reported heartburn, regurgitation and/or chest pain during exercise, irrespective of the intervention. Only a minority of the symptom periods was actually associated with acid reflux and in all cases this concerned periods with heartburn. CONCLUSIONS: Running-induced acid reflux, but not symptoms, were decreased by omeprazole, probably because most symptoms were not related to acid reflux.

Gastrointestinal symptoms in long-distance runners, cyclists, and triathletes: prevalence, medication, and etiology.

OBJECTIVE: The aim of this study was to determine the prevalence of exercise-related gastrointestinal (GI) symptoms and the use of medication for these symptoms among long-distance runners, cyclists, and triathletes, and to determine the relationship of different variables to GI symptoms. METHODS: A mail questionnaire covering the preceding 12 months was sent to 606 well-trained endurance type athletes: 199 runners (114 men and 85 women), 197 cyclists (98 men and 99 women), and 210 triathletes (110 men and 100 women) and sent back by 93%, 88%, and 71% of these groups, respectively. Symptoms were evaluated with respect to the upper (nausea, vomiting, belching, heartburn, chest pain) or lower part of the GI tract (bloating, GI cramps, side ache, urge to defecate, defecation, diarrhea). For statistical analysis, Mann-Whitney U test, Fisher exact test, or Student t test were used. RESULTS: Runners experienced more lower (prevalence 71%) than upper (36%) GI symptoms during exercise. Cyclists experienced both upper (67%) and lower (64%) symptoms. Triathletes experienced during cycling both upper (52%) and lower (45%) symptoms, and during running more lower (79%) than upper (54%) symptoms. Bloating, diarrhea, and flatulence occurred more at rest than during exercise among all subjects. In general, exercise-related GI symptoms were significantly related to the occurrence of GI symptoms during nonexercise periods, age, gender, diet, and years of training. The prevalence of medication for exercise-related GI symptoms was 5%, 6%, and 3% for runners, cyclists, and triathletes, respectively. CONCLUSIONS: Long-distance running is mainly associated with lower GI symptoms, whereas cycling is associated with both upper and lower symptoms. Triathletes confirm this pattern during cycling and running. The prevalence of medication for exercise-related GI symptoms is lower in the Netherlands in comparison with other countries, in which a prevalence of 10-18% was reported. More research on the possible predisposition of athletes for GI symptoms during exercise is needed.

Gastrointestinal symptoms during long-distance walking.

PURPOSE: Gastrointestinal (GI) symptoms are common during prolonged intense exercise. To examine whether GI symptoms are also common during prolonged exercise of lower intensity, we obtained data on incidence, duration, and severity of GI symptoms during four consecutive days walking with a total distance of 203 km for men and 164 km for women. METHODS: The research population consisted of 79 men and 76 women, aged 30-49 yr, who responded to a questionnaire and a diary concerning anthropometric data, activity pattern, dietary intake, and GI symptoms. RESULTS: The results show that 24% of the subjects experienced one or more symptoms. Nausea, headache, and flatulence were the most frequent symptoms. Nine subjects dropped out during the race, two of whom indicated that they stopped as a result of one or more GI symptoms. Logistic regression analysis revealed that the occurrence of GI symptoms was a significant exercise-limiting factor. Univariate analysis showed that incidence and duration of GI symptoms were significantly related to the subjects' experience (number of prior participations to the event), body weight loss during walking, and several components of the diet before and during the event. A significant relationship between GI symptoms and age, gender, training status, and walking speed could not be found. CONCLUSIONS: We conclude that GI symptoms during long-distance walking can impair exercise performance, although these symptoms occur less frequently and are less severe in comparison with prolonged intense exercise.

Safety and effects of physical training in chronic heart failure. Results of the Chronic Heart Failure and Graded Exercise study (CHANGE)

AIMS: Physical training is considered to be safe and beneficial as part of the treatment in heart failure patients. Prospective, sufficiently large studies are still needed to confirm this hypothesis. METHODS: In a prospective study, 80 patients with chronic heart failure class II and III (age, 56.6+/-8.3 years; left ventricular ejection fraction, 26.5+/-9.6%) were randomized to an endurance training group or to a control group with continuation of optimal pharmacological treatment. RESULTS: No training-related adverse event was reported, implying that the training programme was safe for these groups of chronic heart failure patients. Between-group comparison of changes revealed that training increased exercise time (from 608+/-35 to 738+/-40 s, P<0.0001), anaerobic threshold (from 10.5+/-0.4 to 11.8+/-0.3 ml x kg-1 min-1, P<0.05), and decreased the ventilatory equivalent for carbon dioxide at submaximal exercise level (from 2.8+/-0.1 to 2.7+/-0.1, P<0.05). Training did not increase peak oxygen consumption (15.2+/-0.5 to 16. 6+/-0.5 ml x kg-1 min-1, ns). An improvement in patients' assessment of quality of life was observed. There was a significant correlation between physiological and psychological improvements. Training was not effective in patients whose exercise test at entry had a duration of less than 7 min. None of the other baseline data could predict an effective training response. CONCLUSION: Physical training in chronic heart failure patients class II and III is safe and results in significant improvements in exercise time, anaerobic threshold, ventilatory equivalent for carbon dioxide at submaximal exercise level and quality of life.