Biomedical subjects

R J Brummer

Publications and source records attributed to R J Brummer.

At least 19 recordsLinked to original sources

PubMed2001

Abnormal bone turnover in long-standing Crohn's disease in remission.

BACKGROUND: A high prevalence of osteoporosis is found in patients with Crohn's disease. The pathogenesis of this condition seems to be multifactorial and its pathophysiology is still not completely understood. AIM: To elucidate the pathophysiology of osteopenia in quiescent Crohn's disease. METHODS: Bone turnover was studied in 26 patients (13 males and 13 females) with long-standing quiescent Crohn's disease and small bowel involvement. Bone mineral density was assessed by dual energy X-ray absorptiometry. Biochemical markers for bone formation (osteocalcin and bone-specific alkaline phosphatase) and for bone resorption (deoxypyridinoline and collagen type I C-terminal crosslinks) were measured. Urinary calcium excretion was determined. RESULTS: Markers for bone formation were significantly lower in patients than in controls (osteocalcin: P= 0.027, bone-specific alkaline phosphatase: P < 0.001), but both bone resorption markers were not significantly different. Urine calcium excretion was significantly decreased in patients (P=0.002) compared to controls. Bone mineral density of the lumbar spine was significantly and inversely correlated with bone-specific alkaline phosphatase and collagen type I C-terminal crosslinks. CONCLUSIONS: Bone turnover in long-standing Crohn's disease in clinical remission is characterized by suppressed bone formation and normal bone resorption. Urine calcium excretion is decreased. Hence, interventions and therapy should be directed towards the improvement of bone formation.

Absorptiometry, Photon↗

PubMed2001

The effect of different dosages of guar gum on gastric emptying and small intestinal transit of a consumed semisolid meal.

BACKGROUND: There is no consensus about the effect of guar gum supplementation on gastrointestinal transit. It has been suggested that guar gum slows gastric emptying and intestinal transit, thus inducing an increased feeling of satiety. OBJECTIVE: To investigate whether addition of guar gum to a semisolid meal affects gastrointestinal transit. DESIGN: Eight male subjects were randomly studied four times. They consumed a standard semisolid test meal containing either 0 g, 2.5 g, 3.5 g, or 4.5 g of guar gum. The test meals contained 1 mCi 99mTc-hepatate for scintigraphy and 5 g lactulose for the H2-breath test. Scintigraphic scanning was performed for at least two hours, and gastric half-emptying time (T1/2) was calculated. Breath samples were collected at 15 minute intervals and analyzed for H2-enrichment. The orocecal transit time (OCTT) was then determined. A parameter of intestinal transit (PIT) was obtained by subtracting the T1/2 from the OCTT. RESULTS: There were no significant differences (in minutes) between the different tests in both T1/2 (0 g, t = 88.2 +/- 11, 2.5 g, t = 83.3 +/- 11.9, 3.5 g, t = 83.3 +/- 13.6, 4.5 g, t = 72.4 +/- 7.2, p = 0.86) and PIT (0 g, t = 149.9 +/- 26.6, 2.5 g, t = 145.5 +/- 25.6, t = 3.5 g, t = 175.3 +/- 17.6, t = 4.5 g, t = 152.6 +/- 22.4, p = 0.52). CONCLUSION: Addition of guar gum to a semisolid meal up to a dosage of 4.5 g does not affect gastrointestinal transit. Other mechanisms than gastrointestinal motility are involved in a possible satiating effect of guar gum supplementation.

Adult↗

PubMed2001

Gastric digestion of bovine lactoferrin in vivo in adults.

Lactoferrin (LF), an iron-binding glycoprotein present in milk and other endocrine and exocrine secretions, may exert a number of physiologic effects in the intestines. To study the effects of oral LF supplementation in vivo in the gastrointestinal tract, information about the gastric survival of LF in vivo is important. We tested 12 healthy volunteers (age 21 +/- 0.3 y) on 3 separate d according to a randomized, cross-over design. A test drink containing 4.5 g of bovine LF (20% iron-saturated LF; apoLF) in the presence of a gastric pH buffer (0.1 mol/L sodium citrate/citric acid; apoLFbuf), apoLF without the buffer (apoLF) or iron-saturated LF (holoLF) was administered into the stomach using nasogastric intubation. Gastric emptying rate, determined by a marker dilution technique, did not differ among any of these drinks. Gastric survival of LF, analyzed by gel permeation chromatography under denaturing conditions, was 64%, 62% and 79% after consumption of the apoLFbuf, apoLF and holoLF test drinks, respectively. Addition of the gastric pH buffer initially lowered intragastric pH because of its hydroxide buffering effect. However, it did not elevate intragastric pH over a prolonged period and thereby inhibit intragastric LF breakdown. We conclude that after oral administration, substantial amounts of apoLF and holoLF survive gastric transit.

Adult↗

PubMed2001

Low serum and bone vitamin K status in patients with longstanding Crohn's disease: another pathogenetic factor of osteoporosis in Crohn's disease?

BACKGROUND: A high prevalence of osteoporosis is reported in Crohn's disease. The pathogenesis is not completely understood but is probably multifactorial. Longstanding Crohn's disease is associated with a deficiency of fat soluble vitamins, among them vitamin K. Vitamin K is a cofactor in the carboxylation of osteocalcin, a protein essential for calcium binding to bone. A high level of circulating uncarboxylated osteocalcin is a sensitive marker of vitamin K deficiency. AIMS: To determine serum and bone vitamin K status in patients with Crohn's disease and to elucidate its relationship with bone mineral density. METHODS: Bone mineral density was measured in 32 patients with longstanding Crohn's disease and small bowel involvement, currently in remission, and receiving less than 5 mg of prednisolone daily. Serum levels of vitamins D and K, triglycerides, and total immunoreactive osteocalcin, as well as uncarboxylated osteocalcin ("free" osteocalcin) were determined. The hydroxyapatite binding capacity of osteocalcin was calculated. Data were compared with an age and sex matched control population. RESULTS: Serum vitamin K levels of CD patients were significantly decreased compared with normal controls (p<0.01). "Free" osteocalcin was higher and hydroxyapatite binding capacity of circulating osteocalcin was lower than in matched controls (p<0.05 and p<0.001, respectively), indicating a low bone vitamin K status in Crohn's disease. In patients, an inverse correlation was found between "free" osteocalcin and lumbar spine bone mineral density (r=-0.375, p<0.05) and between "free" osteocalcin and the z score of the lumbar spine (r=-0.381, p<0.05). Multiple linear regression analysis showed that "free" osteocalcin was an independent risk factor for low bone mineral density of the lumbar spine whereas serum vitamin D was not. CONCLUSIONS: The finding that a poor vitamin K status is associated with low bone mineral density in longstanding Crohn's disease may have implications for the prevention and treatment of osteoporosis in this disorder.

Absorptiometry, Photon↗

PubMed2001

Epidemiological aspects of irritable bowel syndrome in Europe and North America.

The epidemiology of irritable bowel syndrome (IBS) in Europe and North America was analyzed from published material. The percentage of the population of Western civilisation with IBS symptoms is between 10 and 15% in most studies. The proportion of a Western population visiting a doctor for IBS symptoms is around 5%. The prevalence of IBS and the proportion of consulters do not seem to depend on age in an adult population. The female-to-male ratio of IBS in the population is close to 2. It is higher in IBS consulters in primary care and may be as high as 3 or 4 in tertiary referral centers. At least in patients from these centers, the number of physician visits and colonoscopies is considerable. Most of the consulters get a drug prescription.

Colonic Diseases, Functional↗

PubMed2000

[Gastrointestinal surgery and gastroenterology. IX. Obstipation: etiology and diagnosis].

Constipation and disordered defaecation are symptoms, not disease entities. Usually these symptoms are not caused by organic abnormalities, but by disordered motility of the colon and pelvic floor. Both decreased colonic motility (inertia coli) and increased frequency and amplitude of haustrating colonic contractions in the context of an irritable bowel syndrome may lead to constipation. A third important functional cause of constipation is by paradoxical straining of the pelvic floor muscles during (attempts to) defaecate: anismus. In the diagnosis of constipation the primary aim usually is the exclusion of organic disorders. A plain abdominal X-ray and measurement of colonic transit with radiopaque particles will provide information about the severity of the constipation. Defaecography is indicated primarily if disordered faecal expulsion exists. Anorectal manometry is relevant when Hirschsprung's disease is suspected.

Constipation↗

PubMed2000

[Gastrointestinal surgery and gastroenterology. X. Obstipation: treatment].

Treatment of the symptom of constipation is usually symptomatic. Correction of abnormal lifestyle and dietary habits may constitute a sufficient treatment of constipation. In addition, bulk-forming agents and osmotically active laxatives may be used. Only when these measurements are insufficiently effective, may more drastic treatment options such as contact laxatives and enemas may be used. In cases of spastic pelvic floor syndrome physiotherapy of the pelvic floor is indicated.

Biofeedback, Psychology↗

PubMed2000

Effect of dehydration on gastrointestinal function at rest and during exercise in humans.

Dehydration leads to the aggravation of gastrointestinal (GI) complaints during exercise. The aim of this study was to examine the effect of dehydration on various GI parameters during strenuous exercise. Ten healthy well-trained men were investigated in dehydrated and in euhydrated conditions. Dehydration took place before the experiments using a dehydration regimen in a sauna leading to a 3% loss of body mass. Each experiment consisted of 1 h pre-exercise rest, 1.5 h cycling at 70% maximal exercise intensity, and 3.5 h post-exercise rest. During cycling, liquid gastric emptying (GE), orocaecal transit time (OCTT) and intestinal permeability and glucose absorption were measured. The GI-symptoms were scored using a questionnaire. Body temperature, plasma volume and vasopressin were measured before and after cycling. The GE was significantly slower during dehydration [median time to peak 13C enrichment in the breath sample (13C-TTP) 23.6 min, range 13.7-50.0 min, P = 0.02] than in the control situation (median 13C-TTP 17.1 min, range 9.8-38.4 min). The OCTT was unchanged (median 173 min, range 98-263 min compared to median 128 min, range 98-195 min, P = 0.18). Dehydration did not change intestinal permeability, glucose absorption, plasma volume, rectal temperature or plasma vasopressin concentration. In the dehydration experiment, exercise induced a significant increase in nausea (P = 0.01) and epigastric cramps (P = 0.05), in contrast to the control situation. In both experiments, exercise led to a significant increase in rectal temperature and plasma vasopressin concentration, and a significant decrease in plasma volume. The increase in plasma vasopressin concentration was significantly higher in the dehydration experiment (P = 0.015). No significant differences in either the post-exercise rectal temperatures or in plasma volumes was observed. The difference in GE between the two experiments was significantly correlated with the difference in nausea score (r = 0.87, P = 0.002). We concluded that dehydration leads to a delayed GE but not to differences in OCTT, intestinal permeability or glucose uptake during intense cycling. The delay in GE is significantly associated with an increase in exercise-induced nausea.

Absorption↗

PubMed2000

Comprehensive nutritional status in recently diagnosed patients with inflammatory bowel disease compared with population controls.

OBJECTIVE: Malnutrition is observed frequently in patients with inflammatory bowel disease (IBD). Knowledge of the nutritional status in patients with recently diagnosed IBD is limited. The aim of this study was to establish a comprehensive picture of the nutritional status in recently diagnosed IBD patients. SUBJECTS: Sixty-nine IBD patients (23 Crohn's disease (CD) and 46 with ulcerative colitis (UC)) within 6 months of diagnosis and 69 age- and sex-matched population controls were included in the study. METHODS: The nutritional status was assessed by: (1) body composition (anthropometry and dual-energy X-ray absorptiometry); (2) dietary intake (dietary history); (3) biochemical indexes of nutrition; and (4) muscle strength (isokinetic dynamometer). RESULTS: Body weight and body mass index were significantly lower in UC patients compared with controls. The mean daily intake of carbohydrates was significantly higher in CD patients and the intakes of protein, calcium, phosphorus, and riboflavin were significantly lower in UC patients compared with controls, respectively. Serum concentrations of several nutrients (beta-carotene, magnesium, selenium and zinc) were significantly lower in UC patients compared with controls. Serum vitamin B12 concentration was significantly lower in CD patients. Muscle strength did not significantly differ between IBD patients and controls. CONCLUSIONS: This study showed that the nutritional status of IBD patients was already affected negatively at time of diagnosis. It needs to be elucidated whether nutritional supplementation in recently diagnosed IBD patients may improve the clinical course of the disease.

Adult↗

PubMed2000

Effects of pre- and post-absorptive factors on the lactulose/rhamnose gut permeability test.

It is assumed that the outcome of the lactulose/rhamnose gut permeability test is not influenced by pre- or post-absorptive factors. The aim of our study was to investigate the role of a pre-absorptive factor, i.e. small-intestinal transit, and a post-absorptive factor, i.e. renal clearance. Ten healthy male subjects were studied. Urinary lactulose and rhamnose excretion was measured after intraduodenal administration of lactulose and rhamnose following induction of increased intestinal permeability using chenodeoxycholic acid (chenodiol), in the absence and in the presence of accelerated intestinal transit. Urinary sugar excretion was measured after intravenous administration of either a regular dose (50 mg/50 mg) or a high dose (250 mg/250 mg) of lactulose/rhamnose. The intraduodenal experiments showed that a combination of accelerated small-bowel transit and increased permeability did not lead to significant differences in the recovery of lactulose (P=0.647) or rhamnose (P=0.889), or in the lactulose/rhamnose ratio, compared with those under conditions of increased permeability alone (P=0.68). However, lactulose recovery was significantly lower (P=0.025) after intravenous administration of a high dose of the sugars. There was no significant difference in urinary rhamnose recovery (P=0.575) between the high and the regular doses. This resulted in a significantly lower lactulose/rhamnose ratio (P=0.021) after intravenous administration of a high dose, compared with a regular dose, of the sugars. In conclusion, the assumption that post-absorptive processes do not influence the outcome of the lactulose/rhamnose permeability test appears not to be valid.

Adolescent↗

PubMed2000

Bone mineral density in patients with recently diagnosed inflammatory bowel disease.

BACKGROUND & AIMS: A high prevalence of osteoporosis is reported in inflammatory bowel disease (IBD), and its pathogenesis is not completely resolved. We investigated whether bone mineral density (BMD) in patients with IBD at diagnosis is lower than in population controls, and whether BMD differs between patients with Crohn's disease and those with ulcerative colitis. METHODS: In 68 patients and 68 age- and gender-matched population controls, BMD of total body, spine, and hip was assessed using dual-energy x-ray absorptiometry within 6 months after establishing the diagnosis. Determinants for low BMD were assessed. RESULTS: There were no significant differences in BMD (g/cm(2)) between patients and controls, and no significant differences in BMD between patients with either Crohn's disease or ulcerative colitis. Multivariate regression analysis showed that duration of complaints longer than 6 months before diagnosis (P = 0.041), age (P = 0.019), and body mass index less than 20 kg/m(2) (P = 0.006) significantly correlated with low BMD. CONCLUSIONS: BMD in patients with recently diagnosed IBD was not significantly decreased compared with population controls. Subsequent development of osteoporosis in patients with IBD seems to be a phenomenon related to the disease process and/or the treatment modalities of IBD.

Absorptiometry, Photon↗

PubMed2000

Nutritional supplementation with N-3 fatty acids and antioxidants in patients with Crohn's disease in remission: effects on antioxidant status and fatty acid profile.

In patients with Crohn's disease (CD), malnutrition is frequently observed and is generally accepted to be an important issue. The aim of this study was to investigate the effects of 3 months of supplementation with a liquid formula containing either antioxidants (AO) or n-3 fatty acids plus AO on the antioxidant status and fatty acid profile of plasma phospholipids and adipose tissue, respectively, in patients with long-standing CD currently in remission. In a randomized, double-blind placebo-controlled study, CD patients received either placebo, AO, or n-3 fatty acids plus AO for 3 months in addition to their regular diet. In all, 25/37 CD patients completed the study. AO status was assessed by blood biochemical parameters. A statistical per-protocol analysis was performed. Serum concentrations of selenium, vitamin C, and vitamin E, the activity of superoxide dismutase and total antioxidant status were significantly (p < 0.05) increased after AO supplementation. Furthermore, compared with controls, serum concentrations of beta-carotene, selenium, and vitamin C and the activity of glutathione peroxidase (GPx) were significantly (p < 0.05) lower before supplementation; however, after AO supplementation these levels were not significantly different from controls (except for GPx). N-3 fatty acids plus AO supplementation significantly (p < 0.05) decreased the proportion of arachidonic acid, and increased the proportion of eicosapentanoic acid and docosahexanoic acid in both plasma phospholipids and adipose tissue. Supplementation with antioxidants improved antioxidant status in patients with CD in remission. In addition, supplementation with n-3 fatty acids plus antioxidants significantly changed the eicosanoid precursor profile, which may lead to the production of eicosanoids with attenuated proinflammatory activity. This study indicates that an immunomodulating formula containing n-3 fatty acids and/or AO may have the potential to play a role in the treatment of CD.

Adult↗

PubMed2000

Nutrition in Crohn's disease.

Nutrition plays an important role in Crohn's disease. This review provides further insights into the relationship between nutrition and Crohn's disease and focuses on three different aspects: dietary aetiological factors, nutritional status and nutritional therapy in Crohn's disease.

Crohn Disease↗

PubMed2000

Diet as a risk factor for the development of ulcerative colitis.

OBJECTIVE: Dietary factors have been considered as a possible risk factor for ulcerative colitis (UC). However, available data are inconsistent. The aim of the present study was to evaluate the etiological role of dietary factors in the development of UC. METHODS: Recently diagnosed (<6 Months) UC patients (n = 43) and age- and gender-matched population controls (n = 43) were studied in a case-control design. The crosscheck dietary history method was used to assess dietary intake of 5 yr before the study. Adipose tissue fatty acid composition was used as a biomarker of long-term fat intake. Conditional logistic regression-derived odds ratios (OR), and 95% confidence intervals (CI) were used for statistical analysis. Dietary intake ORs were adjusted for energy intake. RESULTS: High intakes of monounsaturated fat (OR: 33.9 [95% CI 2.6-443.1]), polyunsaturated fat (OR: 5.1 [95% CI 1.0-26.7]), and vitamin B6 (OR: 6.9 [95% CI 1.6-30.7]) were associated with an increased risk to develop UC. No other significant associations were found with UC risk. CONCLUSIONS: High intakes of mono- and polyunsaturated fat and vitamin B6 may enhance the risk of developing UC. Whether this observation is a true risk factor in the development of UC or rather a reflection of a certain dietary lifestyle needs to be investigated.

Adult↗

PubMed1999

Gender specific alterations of body composition in patients with inflammatory bowel disease compared with controls.

OBJECTIVE: To assess body hydration and the distribution of the body water compartments in defined populations of patients with inflammatory bowel disease (IBD) compared with those of matched healthy controls. SUBJECTS: Fifty-two patients with IBD at time of diagnosis (20 patients with Crohn's disease (CD-new) and 32 patients with ulcerative colitis (UC-new)), 40 patients with long-standing CD (CD-long) and 2 matched healthy control groups (n = 52 and n = 40) were recruited for the study. METHODS: Total body water (TBW) and extracellular water (ECW) were measured by deuterium oxide and bromide dilution, respectively. Intracellular water (ICW) was calculated as TBW-ECW. In addition, hydration of fat-free mass (FFM) and the ECW:ICW ratio were calculated. FFM, body fat (BF) and % body fat (%BF) were assessed by dual energy X-ray absorptiometry. RESULTS: In female IBD patients, the ECW:ICW ratio was significantly (P < 0.05) higher than in controls (CD-new: 0.89+/-0.11 vs 0.79+/-0.08, P < 0.01; UC-new: 0.85+/-0.15 vs 0.77+/-0.10, P < 0.05; CD-long: 0.86+/-0.14 vs 0.80+/-0.10, P < 0.05). In these female patients, the ICW:FFM ratio was significantly (P < 0.05) lower than in controls. Fluid shifts were especially pronounced in female patients with recently diagnosed CD. In male patients with recently diagnosed UC and in those with long-standing CD, body weight, body mass index, BF and %BF were significantly (P < 0.05) lower than in controls. No differences in body hydration or body water distribution were observed between male patients and controls. CONCLUSIONS: An altered body water distribution and body hydration was observed in female IBD patients, especially in female patients with recently diagnosed CD.

Absorptiometry, Photon↗

PubMed1999

The sensitivity of the lactulose/rhamnose gut permeability test.

BACKGROUND: The lactulose/rhamnose (L/R) intestinal permeability test is widely used. However, different quantities and proportions of lactulose and rhamnose are used. The aim of this study was to determine whether a low dosage of lactulose is able to discriminate between normal and increased permeability. MATERIALS AND METHODS: Two groups of 10 healthy subjects were studied. In group 1, three different iso-osmolar test solutions were administered on 3 days. The solutions consisted of 10 g of L with 1 g of R, 5 g of L with 0.5 g of R and 1 g of L with 0.1 g of R in 65 mL of water. Group 2 ingested these solutions 1 h after ingestion of 750 mg of chenodeoxycholeic acid (CDCA), which is known to increase permeability. The urinary L/R ratio was determined using high-performance liquid chromatography. Data are presented as medians (range). RESULTS: In group 1, no differences were observed between the three solutions. In Group 2, there was a significant difference (P = 0.045) between the three solutions. The L/R ratios were 0.0079 (0.0024-0.0152) (1L to 0.1R), 0.0138 (0.0066-0.0192) (5L to 0.5R) and 0.0144 (0.0074-0.0374) (10L to 1R). The L/R ratio differed significantly between Groups 1 and 2 (P < 0.001) using the 5L to 0.5R and 10L to 1R solutions respectively. CONCLUSION: If the permeability is increased, the urinary L/R ratio depends on the quantity of lactulose and rhamnose administered in equal proportion. 5L to 0.5R is sufficient to discriminate between a normal and a moderately increased permeability.

Adolescent↗

PubMed1999

Performance of the [13C]-acetate gastric emptying breath test during physical exercise.

BACKGROUND: The gastric emptying rate of liquids can be determined non-invasively using the [13C]-acetate breath test at rest. The aims of our study were to validate this test during physical exercise against the double-sampling method and to evaluate the time needed for intestinal absorption and the delay between absorption and appearance of 13CO2 in breath, both at rest and during exercise. DESIGN: Fifteen well-trained male subjects were investigated. Gastric emptying was determined simultaneously measuring the 13CO2 breath enrichment after intragastric administration of 0.5 L of carbohydrate solution with 150 mg of [13C]-acetate added and by the double-sampling technique (n = 9). In separate tests, 150 mg of [13C]-acetate was also applied intraduodenally and intravenously (n = 6), both at rest and during exercise. Time-to-peak (TTP) 13CO2 enrichment was determined using a curve fit and was considered as the parameter for gastric emptying. RESULTS: TTP enrichment derived from the breath test significantly correlated with the gastric emptying half-time obtained from the gastric aspirates. During exercise, median TTP enrichment values after intragastric, intraduodenal (i.d.) and intravenous (i.v.) administration of [13C]-acetate were 22.3, 10.3 and 5.4 min respectively. During exercise, i.d. and i.v. values were reached significantly earlier than at rest. CONCLUSION: The [13C]-acetate breath test can be used as a non-invasive method to determine relative gastric emptying rates of liquids during exercise, but the results are influenced by the rate of absorption and the time needed for subsequent oxidation of [13C]-acetate and exhalation of 13CO2.

Acetates↗

PubMed1999

The effect of physical exercise on parameters of gastrointestinal function.

Exercise decreases splanchnic bloodflow. Therefore exercise may induce alterations in gastrointestinal (GI) function. In the present study we investigated the effect of high-intensity exercise on oesophageal motility, gastro-oesophageal reflux, gastric pH, gastric emptying, orocaecal transit time (OCTT), intestinal permeability and glucose absorption simultaneously, using an ambulatory protocol. Ten healthy well-trained male subjects underwent a rest-cycling-rest, and a rest-rest-rest protocol (60-90-210 min). Oesophageal motility, gastro-oesophageal reflux and intragastric pH was measured using a trans-nasal catheter. OCTT was measured via breath H2 measurement. A sugar absorption test was applied to determine intestinal permeability and glucose absorption. Gastric emptying was measured using the 13C-acetate breath test. Peristaltic velocity was increased during cycling, compared to rest (4.92 (2.86) vs. 4.03 (1. 48) cm s-1, P = 0.015). Peristaltic contraction pressure at the mid-oesophagus and the duration of the peristaltic contractions at the mid- and distal oesophagus was lower during cycling. There were no differences between the pre-exercise, the exercise and the post-exercise episodes for gastric pH or for both the number and duration of reflux episodes, in both the rest and cycling trials. Neither gastric emptying nor OCTT showed differences between rest and cycling. The lactulose/rhamnose ratio and intestinal glucose absorption were significantly decreased in the cycling trial. Our model enables multiple GI-measurements during exercise. Cycling at 70% Wmax does not lead to differences in reflux, gastric pH or gastrointestinal transit in healthy trained individuals. The distal oesophageal pressure decreases and peristaltic velocity increases. The lactulose/rhamnose ratio and jejunal glucose absorption are decreased during exercise.

Adolescent↗