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Biomedical subjects

Wilfried Kindermann

Publications and source records attributed to Wilfried Kindermann.

At least 19 recordsLinked to original sources
PubMed2007

Cardiac tissue Doppler imaging in sports medicine.

The differentiation of training-induced cardiac adaptations from pathological conditions is a key issue in sports cardiology. As morphological features do not allow for a clear delineation of early stages of relevant pathologies, the echocardiographic evaluation of left ventricular function is the technique of first choice in this regard. Tissue Doppler imaging (TDI) is a relatively recent method for the assessment of cardiac function that provides direct, local measurements of myocardial velocities throughout the cardiac cycle. Although it has shown a superior sensitivity in the detection of ventricular dysfunction in clinical and experimental studies, its application in sports medicine is still rare. Besides technical factors, this may be due to a lack in consensus on the characteristics of ventricular function in relevant conditions. For more than two decades there has been an ongoing debate on the existence of a supernormal left ventricular function in athlete's heart. While results from traditional echocardiography are conflicting, TDI studies established an improved diastolic function in endurance-trained athletes with athlete's heart compared with controls.The influence of anabolic steroids on cardiac function also has been investigated by standard echocardiographic techniques with inconsistent results. The only TDI study dealing with this topic demonstrated a significantly impaired diastolic function in bodybuilders with long-term abuse of anabolic steroids compared with strength-trained athletes without abuse of anabolic steroids and controls, respectively.Hypertrophic cardiomyopathy is the most frequent cause of sudden death in young athletes. However, in its early stages, it is difficult to distinguish from athlete's heart. By means of TDI, ventricular dysfunction in hypertrophic cardiomyopathy can be disclosed even before the development of left ventricular hypertrophy. Also, a differentiation of left ventricular hypertrophy due to hypertrophic cardiomyopathy or systemic hypertension is possible by TDI. Besides the evaluation of different forms of left ventricular hypertrophy, the diagnosis of myocarditis is also of particular importance in athletes. Today, it still requires myocardial biopsy. The analysis of focal disturbances in myocardial velocities might be a promising non-invasive method; however, systematic validation studies are lacking. An important future issue for the implementation of TDI into routine examination will be the standardisation of procedures and the establishment of significant reference values for the above-mentioned conditions. Innovative TDI parameters also merit further investigation.

Anabolic Agents↗
PubMed2006

Bicarbonate infusion and pH clamp moderately reduce hyperventilation during ramp exercise in humans.

To test the hypothesis that the decrease in plasma pH contributes to the hyperventilation observed in humans in response to exercise at high workloads, five healthy male subjects performed a ramp exercise [maximal workload: 352 W (SD 35)] in a control situation and when arterialized plasma pH was maintained at the resting level (pH clamp) by intravenous infusion of sodium bicarbonate [129 mmol (SD 23), beginning at 59% maximal workload (SD 5)]. Bicarbonate infusion did not modify O(2) consumption (Vo(2)) but significantly (P < 0.05) increased arterial Pco(2), plasma bicarbonate concentration, and respiratory exchange ratio (P < 0.05). At the three highest workloads, pulmonary ventilation (Ve) and Ve/Vo(2) were approximately 5-10% lower (P < 0.05) when bicarbonate was infused than in the control situation, and hyperventilation was reduced by 15-30%. These data suggest that the decrease in plasma pH is one of the factors that contribute to the hyperventilation observed at high workloads.

Acid-Base Equilibrium↗
PubMed2006

[Cardiovascular side effects of anabolic-androgenic steroids].

The intake of anabolic-androgenic steroids (AAS) leads to an increase in skeletal muscle mass and is prohibited as a doping measure in sport. AAS abuse is not limited to competitive athletes. It is also prevalent in subjects who do body building or resistance training for cosmetic reasons only. Out of the numerous and partly serious side effects, the cardiovascular ones are presented here. An increase in left ventricular muscle mass is well documented, and some researchers have even reported concentric hypertrophy. By contrast, resistance training without AAS intake does not lead to increased ventricular wall thickness. AAS do not affect the systolic function of the left ventricle, whereas diastolic function might be impaired. Different ultrastructural myocardial alterations have been documented in animal studies. In addition, AAS can induce arterial hypertension. Blood clotting and fibrinolysis are negatively affected, and several case studies of thrombi exist in young strength athletes. Changes in the concentration of blood lipoproteins, particularly a reduction in vessel-protective HDL cholesterol, can lead to early atherosclerosis. Many case reports exist about cardiac deaths in seemingly healthy subjects-most often body builders and other strength athletes. In fatal and nonfatal myocardial infarctions patent coronary arteries were proven frequently. Besides the prothrombotic effects of AAS, an impaired endothelial function and vasospasms are discussed hypothetically as pathomechanisms. Also, cardiomyopathies can occur due to AAS abuse. On the basis of the described possible cardiovascular side effects, it can be concluded that in cases of sudden cardiac deaths in young athletes, a misuse of AS should be excluded.

Adult↗
PubMed2006

Does cumulating endurance training at the weekends impair training effectiveness?

BACKGROUND: Due to occupational restrictions many people's recreational endurance activities are confined to the weekends. We intended to clarify if cumulating the training load in such a way diminishes endurance gains. DESIGN: We conducted a longitudinal study comparing training-induced changes within three independent samples. METHODS: Thirty-eight healthy untrained participants (45+/-8 years, 80+/-18 kg; 172+/-9 cm) were stratified for endurance capacity and sex and randomly assigned to three groups: 'weekend warrior' (n=13, two sessions per week on consecutive days, 75 min each, intensity 90% of the anaerobic threshold; baseline lactate+1.5 mmol/l), regular training (n=12, five sessions per week, 30 min each, same intensity as weekend warrior), and control (n=13, no training). Training was conducted over 12 weeks and monitored by means of heart rate. Identical graded treadmill protocols before and after the training program served for exercise prescription and assessment of endurance effects. RESULTS: VO2max improved similarly in weekend warrior (+3.4 ml/min per kg) and register training (+1.5 ml/min per kg; P=0.20 between groups). Compared with controls (-1.0 ml/min per kg) this effect was significant for weekend warriors (P<0.01) whereas there was only a tendency for the regular training group (P=0.10). In comparison with controls (mean decrease, 3 beats/min), the average heart rate during exercise decreased significantly by 11 beats/min (weekend warriors, P<0.01) and 9 beats/min (regular training, P<0.05). There was no significant difference, however, between the weekend warrior and regular training groups (P=0.99). CONCLUSION: In a middle-aged population of healthy untrained subjects, cumulating the training load at the weekends does not lead to an impairment of endurance gains in comparison with a smoother training distribution.

Adult↗
PubMed2006

Reproducibility and clinical significance of exercise-induced increases in cardiac troponins and N-terminal pro brain natriuretic peptide in endurance athletes.

BACKGROUND: Cardiac troponins I and T and brain natriuretic peptide are the accepted standards to serologically identify myocardial necrosis and elevated wall stress. In addition, they allow risk stratification in cardiovascular patients. The clinical significance of increases in cardiac markers after strenuous endurance exercise in obviously healthy athletes is unclear. DESIGN: We therefore examined the reproducibility and clinical significance of exercise-induced increases in cardiac troponins I and T and N-terminal pro brain natriuretic peptide after two standardized endurance exercise trials in healthy endurance athletes with prior competition-induced elevations of cardiac troponins (I, 0.08-1.93 mug/l; T, 0.01-0.56 mug/l). METHODS: Twenty male athletes (36+/-7 years; VO2max: 60+/-5 ml/min per kg) completed a 1-h and a 3-h exercise study (exercise intensities 100 and 75%, respectively, of the individual anaerobic threshold) on two different days in randomized order to determine cardiac markers before, 30 min and 3 h after exercise. In addition to pre- and post-exercise echocardiography including tissue Doppler imaging, delayed enhancement magnetic-resonance-imaging was performed after a 3-h exercise study to detect myocardial necrosis. RESULTS: A marginal increase in cardiac troponin I was documented after both exercise trials (from 0.02 to 0.03 mug/l; P < 0.001). Cardiac troponin T remained without significant changes. N-terminal pro brain natriuretic peptide increased by 9 and 30 ng/l after 1-h and 3-h exercise studies, respectively (P < 0.001). In contrast to cardiac troponins, increases in N-terminal pro brain natriuretic peptide after competition correlated with those after 1-h exercise study (rho = 0.88) and 3-h exercise-study (rho = 0.82). No pathologies were demonstrated by echocardiography or delayed-enhancement magnetic resonance imaging. CONCLUSIONS: Due to the missing reproducibilty and evidence of myocardial damage, exercise-induced increases in cardiac troponins may represent a physiologic reaction under special conditions and seem to be without pathological significance in healthy athletes.

Adult↗
PubMed2006

Effects of graded carbohydrate supplementation on the immune response in cycling.

PURPOSE: This study examined the acute immune response after three standardized cycling sessions of 4-h duration in the field with varying carbohydrate (CHO) supplementation in a randomized, double-blind, placebo-controlled fashion. We hypothesized that the ingestion of carbohydrate (6 or 12% CHO beverages; placebo (P) without CHO) during exercise attenuates the exercise-induced immune response in a dose-dependent manner. METHODS: A total of 14 male competitive cyclists and triathletes (age: 25 +/- 5 yr; height: 180 +/- 7 cm; weight: 72 +/- 9 kg; VO2max: 67 +/- 6 mL.min(-1).kg(-1)) cycled for 4 h on a 400-m track at a given workload of 70% of the individual anaerobic threshold (198 +/- 21 W). Leukocyte and lymphocyte subpopulations were measured by flow cytometry before, immediately, and 1 and 19 h after exercise. In addition, C-reactive protein (CRP) interleukin 6 (IL-6), and cortisol were determined. RESULTS: The exercise-induced increase in leukocytes, neutrophils, and monocytes was significantly attenuated to the same extent by 6 and 12% CHO (P < 0.001). No differences could be demonstrated for lymphocytes and natural killer cells. The increase in CRP was attenuated significantly by 12% CHO only (P < 0.05), whereas the increase in cortisol and IL-6 was significantly reduced by 6 and 12% CHO (P < 0.001). The postexercise neutrophilia, which dominated the exercise-induced leukocytosis, was strongly related to the postexercise concentration of cortisol (r = 0.72; P < 0.001). CONCLUSIONS: Because of the lacking dose-dependent difference, the ingestion of at least 6% CHO beverages can sufficiently attenuate the exercise-induced immune response and stress, especially in phagocytizing cells (neutrophils and monocytes) by the reduced release of cortisol.

Adult↗
PubMed2005

Injuries in female soccer players: a prospective study in the German national league.

BACKGROUND: In contrast to the high number of studies about soccer injuries in men, epidemiologic data in high-level female soccer players are scarce. PURPOSE: Analysis of injury incidence in elite female soccer players. STUDY DESIGN: Descriptive epidemiology study. METHODS: There were 165 female soccer players (age, 22.4 +/- 5.0 years) from 9 teams competing in the German national league, who were followed for one complete outdoor season. Their trainers documented the exposure to soccer on a weekly basis for each player, and the team physical therapists reported all injuries with regard to location, type, and circumstances of occurrence. An injury was defined as any physical complaint associated with soccer that limited sports participation for at least 1 day. RESULTS: There were 241 injuries sustained by 115 players (70%) reported; 39 injuries (16%) were owing to overuse, and 202 injuries (84%) were traumatic. Overall, 42% of the traumatic injuries occurred during training (2.8/1000 hours of training; 95% confidence interval, 2.2-3.4) and 58% during matches (23.3/1000 match hours; 95% confidence interval, 19.1-27.5); 102 of the traumatic injuries were caused by a contact situation, whereas 95 occurred without any contact. Most injuries (80%) were located at the lower extremities, concerning mainly the thigh (n = 44), knee (n = 45), and ankle (n = 43). Ankle sprain (n = 37) was the most often diagnosed injury. There were 51% minor injuries, 36% moderate injuries, and 13% major injuries. Eleven anterior cruciate ligament ruptures were observed during the season. CONCLUSION: The results revealed a high injury incidence rate in games as well as a comparably low incidence rate during training. An important finding of this investigation was the frequent occurrence of anterior cruciate ligament ruptures. Preventive measures should thus focus on the high prevalence of anterior cruciate ligament tears, mostly occurring in noncontact situations.

Adult↗
PubMed2005

An alternative approach for exercise prescription and efficacy testing in patients with chronic heart failure: a randomized controlled training study.

BACKGROUND: Prescription of endurance training and documentation of its efficacy in patients with chronic heart failure (CHF) is usually done with reference to maximal ergometric measurements which are subject to form on the day changes and motivational influences. However, the use of submaximal parameters might represent an alternative approach. METHODS: This was tested in 54 patients with CHF (57 +/- 10 years, NYHA II: n = 40; NYHA III: n = 14) who were randomized into training (T; n = 26) or control group (CO; n = 28). Training consisted of 45 minutes cycling at an intensity corresponding to the anaerobic threshold (AT) and was conducted for 12 weeks, 4 to 5 times per week. Cardiorespiratory exercise testing was done before and after the experimental phase. Changes in well-being were investigated using a 5-point Likert scale. RESULTS: A significant rightward shift in the heart rate curve was demonstrated in T compared with CO (P = .01; T: decrease in resting heart rate by 8 per minute, during exercise by 7 to 11/min; CO: -1 and -1 to -3 per minute, respectively). Anaerobic threshold increased significantly by 11.6% in T (+0.11 +/- 0.11 L min(-1) oxygen uptake) compared with CO (-0.02 +/- 0.10 L min(-1)). Positive changes in well-being were significantly larger in T (P < .01). CONCLUSIONS: In patients with CHF, training can be prescribed and its efficacy can be evaluated by the exclusive use of submaximal parameters. Anaerobic threshold represents an appropriate training intensity in this population.

Aged↗
PubMed2005

Independent elevations of N-terminal pro-brain natriuretic peptide and cardiac troponins in endurance athletes after prolonged strenuous exercise.

BACKGROUND: Although elevated resting brain natriuretic peptide (BNP) concentrations reflect heart disease, the meaning of exercise-induced increases is poorly understood and has been examined in small groups only. Therefore, the present study aimed to examine the increase in N-terminal pro-brain natriuretic peptide (NT-proBNP) and relations to cardiac troponin I and T (cTnI, cTnT) elevations after prolonged strenuous exercise in a large cohort of athletes. METHODS: We examined exercise-induced changes in NT-proBNP, cTnI, and cTnT in 105 obviously healthy endurance athletes (40 +/- 8 years) before and after prolonged strenuous exercise. Blood samples were taken before, 15 minutes, and 3 hours after a marathon (n = 46), a 100-km run (n = 14), and a mountain bike marathon (n = 45). RESULTS: Eighty-one of 105 athletes exceeded the upper reference limit of NT-proBNP (males/females 88:153 ng/L) after exercise. NT-proBNP increased in all 3 events (P < .001) with the highest increase in the 100-km runners (median increase 200 ng/L; 25th/75th percentile 115/770 ng/L), which differed from the increase in the marathon (97 ng/L; 36/254 ng/L) or the mountain bike marathon (78 ng/L; 37/196 ng/L) (P < .01). Cardiac troponin I exceeded 0.04 microg/L in 74%; cTnT exceeded 0.01 microg/L in 47% of athletes after exercise. NT-proBNP was not related to exercise-induced increases in cTnI or cTnT, but correlated with exercise time (r = 0.55, P < .001). CONCLUSIONS: Increases in NT-proBNP can be found in a major part of obviously healthy athletes after prolonged strenuous exercise. The release of BNP during and after exercise may not result from myocardial damage but may have cytoprotective and growth-regulating effects. The different nature of exercise-induced increases in BNP and cardiac troponins has to be elucidated in the future.

Adult↗
PubMed2005

Running exercise of different duration and intensity: effect on endothelial progenitor cells in healthy subjects.

BACKGROUND: Increased numbers of circulating endothelial progenitor cells (EPC) are associated with improved vascular function. Exercise is a central component of the primary prevention of vascular diseases. The effect of physical activity on circulating EPC in healthy individuals is not known. DESIGN: A prospective crossover study. METHODS AND RESULTS: In order to study a potential link between the extent of physical exercise and progenitor cells in humans, EPC were quantified by flow cytometry and cell culture in 25 healthy volunteers undergoing three protocols of running exercise. Intensive running, defined as 30 min at 100% of the velocity of the individual anaerobic threshold (IAT; approximately 82% maximal oxygen consumption; VO2max), as well as moderate running with 30 min at 80% of the velocity of the IAT ( approximately 68% VO2max), increased circulating EPC numbers to 235+/-93% and 263+/-106% of control levels, respectively. However, moderate short-term running for 10 min did not upregulate EPC counts. The maximum increase in circulating EPC numbers was observed 10-30 min after intensive running. Exercise increased EPC migratory and colony-forming capacity. CONCLUSIONS: Intensive and moderate exercising for 30 min, but not for 10 min, increased circulating levels of EPC, which may represent an important beneficial outcome of physical exercise. The data support the notion that increased numbers of EPC correlate with cardiovascular health and suggest EPC quantification as a novel surrogate parameter of the vascular effects of exercising.

Adult↗
PubMed2005

Altered vitamin B12 status in recreational endurance athletes.

This study aimed to compare the vitamin B(12)and folate status of recreational endurance athletes and inactive controls by modern biomarkers. In 72 athletes (38 +/- 7 y) and 46 inactive controls (38 +/- 9 y) serum levels of vitamin B(2), methylmalonic acid (MMA), holotranscobalamin II (holoTC), folate, and homocysteine (Hcy) were measured. Vitamin B(12)and folate levels of both groups were comparable, but athletes had higher median (25.-75. percentile) MMA [242 (196 to 324) versus 175 (141 to 266) nmol/L] and holoTC concentrations [67 (52 to 93) versus 55 (45 to 70) pmol/L] than controls. Hcy was slightly lower in athletes [9.2 (7.2 to 12.6) versus 10.8 (8.9 to 12.9) nmol/L]. In controls, we found the following correlations: vitamin B(12)and MMA (r = -0.38), vitamin B(12)and holoTC (r = 0.51), MMA and holoTC (r = -0.36). In athletes, MMA did not correlate with vitamin B(12)and holoTC. Our data suggests an altered vitamin B(12)metabolism in recreational athletes that needs further investigation.

Adult↗
PubMed2005

Running 8000 m fast or slow: Are there differences in energy cost and fat metabolism?

PURPOSE: To compare energy requirements and substrate use for running a given distance fast versus slow under field conditions. METHODS: Ten males and four females who were moderately endurance trained (32 +/- 6 yr; 71 +/- 11 kg; body mass index: 22.7 +/- 2.3 kg x m(-2); VO2max: 62.0 +/- 6.0 mL x min(-1) x kg(-1); individual anaerobic threshold [IAT]: 13.7 +/- 1.4 km x h(-1)) performed an incremental running protocol to determine IAT. Subsequently, two 8000-m runs at 70 and 95% IAT were performed on separate days in randomized order on an indoor track. Energy expenditure (EE) was measured by means of a portable metabolic device (indirect calorimetry). A meaningful difference in EE was defined as >10%. RESULTS: EE was significantly greater during the 95% IAT run than during the 70% IAT run (2650 +/- 276 and 2554 +/- 348 kJ, respectively). However, this difference was only 3.8 +/- 4.8%. Including measurements up to 10 min postexercise, the difference rose to 5.1 +/- 4.7% (95% IAT: 2830 +/- 301 kJ; 70% IAT: 2692 +/- 368 kJ). There was no significant difference between the absolute amounts of fat oxidized during the runs (70% IAT: 26 +/- 5 g; 95% IAT: 20 +/- 5 g). During the 95% IAT run, significantly more carbohydrates were metabolized than during the 70% IAT run (108 +/- 14 and 90 +/- 5 g, respectively). The difference in EE between the two runs increased from the first to the third part of the running distance (first: no significance; second: P < 0.01; third: P < 0.001). CONCLUSION: Energy requirements for a commonly run distance in recreational endurance training differ significantly but not relevantly between slow and fast speeds. However, increasing total running distance might lead to larger differences.

Adipose Tissue↗
PubMed2004

Clinical significance of increased cardiac troponins T and I in participants of ultra-endurance events.

Of 105 asymptomatic finishers of endurance competitive events lasting several hours, increased blood concentrations of cardiac troponins T and I above the 99% upper reference values were found in 24 and 34 subjects, respectively; N-terminal pro-brain natriuretic peptide was also significantly increased. Within 3 months after the events, 21 troponin-positive participants underwent an extensive cardiac examination, which in all but 1 (critical coronary heart disease) revealed no signs of persistent cardiac damage.

Adult↗
PubMed2004

Different effects of two regeneration regimens on immunological parameters in cyclists.

PURPOSE: To investigate the effect of 4-d active regeneration of different duration on immunological parameters after 2 wk of intensive training. METHODS: In a cross-over design 11 male cyclists conducted 13 d of intensive training followed by 4 d of low-intensity cycling for either 1 or 3 h each day (sequence randomized). Before the intensive training (test 1), between training and regeneration (test 2), and after the regeneration period (test 3), subjects were tested in the lab: venous blood sampling (immunological parameters; flow cytometry) and incremental exercise stage test on acycle ergometer. RESULTS: Average values of lymphocytes and natural killer (NK) cells decreased significantly from test 1 to test 2 and were influenced differently by 1- and 3-h cycling (P = 0.018 and 0.039, respectively); 1-h cycling restored values from test 1, whereas 3 h led to a further decrease in lymphocyte and NK cell concentrations. This pattern was resembled by the courses of maximal heart rate and maximal blood lactate concentration during incremental cycling exercise. In leukocytes, tests 2 and 3 differed significantly from test 1 (P = 0.048 and 0.031, respectively), but there was no significant effect of the regeneration duration (P = 039). Neither the concentration of neutrophils nor the neutrophil oxidative burst was significantly influenced by the training period or by one of the regeneration phases. CONCLUSIONS: The present results indicate that low-intensity regenerative training sessions in cyclists should preferably be conducted for shorter durations than 3 h. It was demonstrated that 4-d cycling of 1 h each day reversed ergometric and immunological changes indicative of fatigue after 2 wk of intensive training.

Adult↗
PubMed2004

Long-distance mountain biking does not disturb the measurement of total, free or complexed prostate-specific antigen in healthy men.

PURPOSE: Mechanical manipulation of the prostate is a generally accepted interfering factor for the measurement of prostate-specific antigen (PSA). However, only few studies have focused on common daily mechanical manipulations, such as bicycle riding. Furthermore, physical exercise is also supposed to modulate PSA serum concentration. Long-distance mountain biking is an excellent model to study the combined effect of mechanical prostate manipulation by bicycle riding and strenuous endurance exercise on total, free and complexed PSA (tPSA, fPSA, cPSA). MATERIALS AND METHODS: We investigated tPSA, fPSA and cPSA in 42 healthy male cyclists (mean age 35+/-6 years) before and after a 120 km off-road mountain bike race. Blood sampling was done before, 15 min and 3 h after the race. RESULTS: Mean race time was 342+/-65 min. All athletes had normal serum levels of tPSA, fPSA or cPSA. None of these parameters was modified by the race. CONCLUSIONS: In healthy men the measurement of tPSA, fPSA and cPSA is not disturbed by preceding long distance mountain biking or endurance exercise. Based on the present data, there is no evidence for a recommendation to limit bicycle riding or physical activity before the measurement of tPSA, fPSA or cPSA.

Adult↗
PubMed2004

Exercise programmes for patients with chronic heart failure.

The safety and efficacy of exercise training in patients with chronic heart failure (CHF) have been reported in a large number of scientific studies, with endurance training representing the most frequently applied training stimulus. Beneath the common continuous method of endurance training, the interval method (short bouts of intense exercise interspersed with pre-scheduled rest intervals), was also applied in some studies. Ergometric testing is a prerequisite for all individualised training prescription and is an appropriate method of efficacy documentation. However, there is a surprisingly large range of exercise intensities being prescribed to patients with CHF. Most of the prescription models refer to maximal ergometric measurements. Submaximal references from lactate and ventilatory curves represent an alternative method in measuring accuracy and efficacy of training. The course of heart rate during submaximal incremental exercise can be reliably used to indicate endurance gains in CHF. Some positive reports exist for carefully executed strength endurance training for patients with CHF and there are convincing arguments for the use of coordination and flexibility exercises; however, substantial scientific evidence is lacking.

Cardiovascular System↗