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Biomedical subjects

S Kriemler

Publications and source records attributed to S Kriemler.

13 recordsLinked to original sources
PubMed2006

Physical activity is independently related to aerobic capacity in cystic fibrosis.

It is unclear whether a relationship between physical activity (PA) and maximal oxygen uptake (V'(O2,max)) exists in cystic fibrosis (CF) and, if so, whether the relationship reflects a direct effect or is mediated by the effects of confounding variables, such as pulmonary or muscle function. The objective of the present study was to determine the relationship between PA and V'(O2,max) in CF while adjusting for possible influences of confounding factors. In total, 36 female and 35 male patients with CF from Germany and Switzerland (aged 12-40 yrs, forced expiratory volume in one second (FEV1) 25-107% predicted) were studied. A Wingate test was employed to measure muscle power. PA was monitored for 7 days and expressed in two ways: 1) average daily accelerometer count (ADAC) and 2) time spent in moderate-to-vigorous PA (MVPA). V'(O2,max) was determined during an incremental cycle exercise test to volitional fatigue. PA was positively related to V'(O2,max). In a multiple linear regression analysis, height, sex, FEV1, muscle power and ADAC (additionally explained variance 2.5%) or time spent in MVPA (additionally explained variance 3.7%) were identified as independent predictors of V'(O2,max). In conclusion, high levels of physical activity in addition to good muscular and pulmonary functions are associated with a high aerobic capacity in cystic fibrosis.

Adolescent↗
PubMed2000

[Swiss registry for patients with cystic fibrosis: design, programming, implementation and first examples of use].

The Swiss Registry for Cystic Fibrosis (SRCF) was designed to collect demographic, clinical and therapeutic data from patients with cystic fibrosis (CF) in Switzerland. It was designed, programmed and implemented for standalone application in Swiss cystic fibrosis centres. It is part of the European Registry for Cystic Fibrosis (ERCF), which has been implemented in Europe to collect data on the use and safety of dornase alpha (Pulmozyme) in the treatment of cystic fibrosis. At the time of first evaluation 245 cystic fibrosis patients are registered, their mean age is 13 years, and 17% are over 18. In larger databases in Germany or North America we observe comparable demographic data, similar degrees of severity and similar therapeutic approaches to those in Swiss cystic fibrosis patients. The aim of the Swiss Registry is to cover the maximum possible number of cystic fibrosis patients from this country.

Adolescent↗
PubMed2000

Anaerobic performance in 5- to 7-yr-old children of low birthweight.

PURPOSE: This study was intended to determine whether anaerobic muscle performance is deficient in 5- to 7-yr-old children of extremely low birthweight (ELBW, 500-999 g) and very low birthweight (VLBW, 1000-1499 g). METHODS: Fourteen ELBW and 20 VLBW children were compared with 24 normal birthweight (NBW, >2500 g) term controls. Peak (PP) and mean (MP) muscle power were determined by the Wingate anaerobic test. Bioimpedance analysis and anthropometry were done to assess fat-free mass (FFM) and lean cross-sectional area of the thigh and calf. RESULTS: The ELBW group had significantly lower MP and PP, compared with the VLBW and, in particular, with the NBW group. This lower performance was apparent also when values were corrected for total body mass (MP) and FFM (MP and PP), but not when corrected for cross-sectional area of thigh and calf. CONCLUSION: The lower anaerobic muscle performance in ELBW children may be partly due to their smaller muscle mass, but may also reflect a low percentage of fast-twitch muscle fibers, low muscle phosphagen content, or deficiency in motor control.

Body Composition↗
PubMed1999

Preventing dehydration in children with cystic fibrosis who exercise in the heat.

PURPOSE: In healthy children who exercise in the heat, the addition of flavor, carbohydrate, and 18 mmol x L(-1) NaCl to water induced a major increase in voluntary drink intake compared with the intake of unflavored water. This increase was sufficient to prevent voluntary dehydration. We hypothesized that, to achieve a similar effect in children with cystic fibrosis (CF), whose NaCl losses in sweat are markedly excessive, the drink should include an NaCl concentration higher than 18 mmol x L(-1). METHODS: Eleven subjects with CF (6 girls, 5 boys, ages 10.9-19.5 yr) attended three 3-h sessions of intermittent exercise of moderate intensity (four 20-min bouts), at 35 degrees C, 50% relative humidity. Either water (W), flavored water (FW), or a 30 mmol x L(-1) NaCl plus 6% carbohydrate solution (Na30) was offered ad libitum, in a counterbalanced sequence. Six subjects performed an additional session in which they drank a 50 mmol x L(-1) NaCl-6% CHO solution (Na50). RESULTS: There was no significant drink effect on body fluid balance, core temperature, heart rate, or serum electrolytes with W, FW, or Na30. Serum osmolality decreased throughout the sessions from 290.6 +/- 1.1 (mean +/- SEM) to 281.3 +/- 1.2 mmol x kg(-1) (P < 0.0005), serum sodium from 143.1 +/- 0.5 to 141.1 +/- 0.7 mmol x L(-1) (P = 0.01) and serum chloride from 109.1 +/- 0.5 to 107.5 +/- 0.5 mmol X L(-1) (P < 0.001). In contrast, the 50 mmol x L(-1) NaCl drink induced a near significant (P = 0.08) higher fluid intake, and it significantly ameliorated the rate of progressive dehydration. CONCLUSIONS: The marked loss of NaCl in the sweat of CF patients may induce an hypo-osmolar state in the serum, even when the drink contains 30 mmol x L(-1) NaCl. This may diminish the thirst drive triggered by hypothalamic osmoreceptors and may lead to voluntary dehydration. A flavored drink with an even higher salt content (50 mmol X L(-1)), however, enhances drinking and attenuates the voluntary dehydration.

Adolescent↗
PubMed1999

Impact of a single exercise bout on energy expenditure and spontaneous physical activity of obese boys.

The main objective of the present study was to determine whether a structured, laboratory-based exercise task would modify the energy expenditure (EE) and the pattern of spontaneous physical activity (PA) of obese boys on the day of an exercise laboratory visit and on the following day. Fourteen 10- to 15-y-old moderately obese (36.6+/-3.3% fat) boys volunteered. They each had three laboratory visits, I wk apart. In one visit, they performed a strenuous 50-min cycling task; in another, a 30-min medium-intensity cycling task; and in another (which served as placebo), they did not exercise. PA was monitored the day before (d 1), during (d 2), and after (d 3) each laboratory visit by use of a heart rate monitor and a 12-h recall interview. EE was calculated from minute-by-minute heart rate and each child's predetermined relationship between oxygen uptake and heart rate. EE and PA were analyzed from 1300 to 1900 h each day using 15-min intervals. EE tended to decrease (p < 0.087) in the afternoon of all d 2 compared with d 1, and it increased on d 3 after the medium-intensity exercise (p < 0.0005). EE during d 2 and 3 combined, compared with d 1, decreased after the high-intensity exercise (534.2 versus 564.3 kJ/h, p < 0.05). It increased after the medium-intensity exercise (561.8 versus 526.7 kJ/h, p = 0.052) and was not affected after the placebo visit (589.4 versus 574.3 kJ/h). Time spent outdoors was consistently reduced on the day of laboratory visit compared with the day before and after the visit, regardless of the contents of intervention. In conclusion, a single laboratory visit is followed by a reduction in EE and PA on the day of intervention. However, its effect on EE the following day may be dose dependent: medium-intensity exercise induces an increase in EE, but high-intensity exercise causes a decrease in EE. One implication is that intervention by physical training should employ medium-intensity exercise to enhance the EE of obese boys.

Adolescent↗
PubMed1998

Treatment with human growth hormone in patients with Prader-Labhart-Willi syndrome reduces body fat and increases muscle mass and physical performance.

UNLABELLED: Twelve children with documented Prader-Labhart-Willi syndrome were treated with human growth hormone (24 U/m2/week) during 1 year. The children were divided into three groups: group 1: overweight and prepubertal (n=6, age 3.8-7.0 years); group 2: underweight and prepubertal (n=3, age 0.6-4.1 years); group 3: pubertal (n=3, age 9.2-14.6 years). In group 1, height increased from -1.7 SD to -0.6 SD, while weight decreased from 1.1 SD to 0.4 SD, with a dramatic drop in weight for height from 3.8 SD to 1.2 SD. Hand length increased from -1.5 SD to -0.4 SD and foot length from -2.5 SD to -1.4 SD. Body fat, measured by dual X-ray energy absorptiometry, dropped by a third, whereas muscle mass increased by a fourth. Physical capability (Wingate test) improved considerably. The children were reported to be much more active and capable. In group 2, similar changes were seen, but weight for height increased, probably because muscle mass increase exceeded fat mass decrease. Changes in group 3 were similar as in group 1, even though far less distinct. CONCLUSION: Growth hormone treatment in Prader-Labhart-Willi syndrome led to dramatic changes: distinct increase in growth velocity, height and muscle mass, as well as an improvement in physical performance. Fat mass and weight for height decreased in the initially overweight children, and weight for height increased in underweight children.

Adipose Tissue↗
PubMed1998

Consistency in preventing voluntary dehydration in boys who drink a flavored carbohydrate-NaCl beverage during exercise in the heat.

Twelve 10- to 12-year-old healthy boys performed six 70-min intermittent exercise sessions (three 20-min cycling bouts at 50% VO2max with 5 min rest in between) over a 2-week period at 35 +/- 1 degrees C, 50 +/- 5% or 60 +/- 5% relative humidity. Subjects drank grape-flavored solution with 6% carbohydrate (2% glucose, 4% sucrose) and 18.0 mmol.L-1 NaCl ad libitum. Body weight (BW), heart rate, rectal temperature, thirst, and stomach fullness perception were monitored periodically. There were no differences among the six sessions in voluntary drink intake (765-902 g), hydration level (+0.75 to +1.07%BW), sweating rate (245-263 g.m-2.hr-1), and the other physiological and perceptual variables. A positive fluid balance was achieved in 67 out of 72 sessions. Voluntary drink intake of grape-flavored carbohydrate-NaCl beverage was consistently sufficient to prevent dehydration in 10- to 12-year-old boys during repeated exposures of exercise in the heat. This effect is likely to be achieved through a combination of physiological and behavioral mechanisms.

Beverages↗
PubMed1998

Kinetics of oxygen uptake at the onset of exercise in boys and men.

The objective of this study was to compare the O2 uptake (VO2) kinetics at the onset of heavy exercise in boys and men. Nine boys, aged 9-12 yr, and 8 men, aged 19-27 yr, performed a continuous incremental cycling task to determine peak VO2 (VO2 peak). On 2 other days, subjects performed each day four cycling tasks at 80 rpm, each consisting of 2 min of unloaded cycling followed twice by cycling at 50% VO2 peak for 3.5 min, once by cycling at 100% VO2 peak for 2 min, and once by cycling at 130% VO2 peak for 75 s. O2 deficit was not significantly different between boys and men (respectively, 50% VO2 peak task: 6.6 +/- 11.1 vs. 5.5 +/- 7.3 ml . min-1 . kg-1; 100% VO2 peak task: 28.5 +/- 8.1 vs. 31.8 +/- 6.3 ml . min-1 . kg-1; and 130% VO2 peak task: 30.1 +/- 5.7 vs. 35.8 +/- 5.3 ml . min-1 . kg-1). To assess the kinetics, phase I was excluded from analysis. Phase II VO2 kinetics could be described in all cases by a monoexponential function. ANOVA revealed no differences in time constants between boys and men (respectively, 50% VO2 peak task: 22. 8 +/- 5.1 vs. 26.4 +/- 4.1 s; 100% VO2 peak task: 28.0 +/- 6.0 vs. 28.1 +/- 4.4 s; and 130% VO2 peak task: 19.8 +/- 4.1 vs. 20.7 +/- 5. 7 s). In conclusion, O2 deficit and fast-component VO2 on-transients are similar in boys and men, even at high exercise intensities, which is in contrast to the findings of other studies employing simpler methods of analysis. The previous interpretation that children rely less on nonoxidative energy pathways at the onset of heavy exercise is not supported by our findings.

Adult↗
PubMed1994

[Development and adaptation of tensile strength by bones in the extremities in response to physical training exemplified by the tibia].

Results from an in vivo assessment of the bending stiffness of human tibiae with a new method demonstrate that bone mineral measurements are not a suitable predictor to evaluate changes of mechanical properties of long bones. In a study on 559 male military recruits, the bone mineral at tibial shaft resulted in a mean increase of +1.8% during 15 weeks of exercise. The bending stiffness however increased about 25%. An additional test 24 months later on a sample indicated that the increase of bone mineral content was only due to the natural maturation of bone. The bending stiffness however, decreased by about 6% demonstrating the earlier training effect. No correlation between bone mineral and bending stiffness could be found neither in absolute values nor in difference between the three measurements. At the same time first results of a normative study on children (9 to 18 years old, male and female) and on women (up to 80 years old) are presented.

Adolescent↗
PubMed1987

Successful treatment of acute mountain sickness with dexamethasone.

A double blind, randomised, placebo controlled trial of treatment with dexamethasone for acute mountain sickness was performed in the Capanna "Regina Margherita" at an altitude of 4559 m in the Alps Valais. After 12-16 hours of treatment (8 mg dexamethasone initially, followed by 4 mg every six hours) the mean acute mountain sickness score decreased significantly from 5.4 to 1.3, and eight of 17 patients became totally asymptomatic. Mean arterial oxygen saturation rose from 75.5% to 82.0%, and there was a small increase in standard spirometric measurements. In the placebo group none of these variables changed significantly. It is concluded that dexamethasone may be used as emergency treatment for acute mountain sickness to facilitate safe descent to a lower altitude.

Acute Disease↗
PubMed1987

Enhanced fibrin formation in high-altitude pulmonary edema.

Blood coagulation, fibrinolysis, and arterial blood gases were examined in 66 nonacclimatized mountaineers at 4,557 m. Subjects were classified according to a clinical score as healthy (n = 25), having mild acute mountain sickness (AMS) (n = 24), showing severe AMS (n = 13), and suffering from high-altitude pulmonary edema (HAPE) (n = 4). Coagulation times, euglobulin lysis time, and fibrin(ogen) fragment E were normal in all groups without significant changes. Fibrinopeptide A (FPA), a molecular marker of in vivo fibrin formation, was elevated in HAPE to 4.2 +/- 2.7 ng/ml (P less than 0.0001) compared with the other groups showing mean values between 1.6 +/- 0.4 and 1.8 +/- 0.7 ng/ml. FPA was normal in one patient with HAPE, however. Severe AMS was accompanied by a significant decrease in arterial PO2 due to an increase in alveolar-arterial O2 difference, whereas arterial PCO2 did not change significantly. We conclude that activation of blood coagulation is not involved in the pathogenesis of AMS and the impairment of gas exchange in this disease. Fibrin generation occurring in HAPE is probably an epiphenomenon of edema formation.

Adult↗