Size and blood flow of central and peripheral arteries in highly trained able-bodied and disabled athletes

In a cross-sectional study, central and peripheral arteries were investigated noninvasively in high-performance athletes and in untrained subjects. The diastolic inner vessel diameter (D) of the thoracic and abdominal aorta, the subclavian artery (Sub), and common femoral artery (Fem) were determined by duplex sonography in 18 able-bodied professional tennis players, 34 able-bodied elite road cyclist athletes, 26 athletes with paraplegia, 17 below-knee amputated athletes, and 30 able-bodied, untrained subjects. The vessel cross-sectional areas (CSA) were set in relation to body surface area (BSA), and the cross-section index (CS-index = CSA/BSA) was calculated. Volumetric blood flow was determined in Sub and Fem via a pulsed-wave Doppler system and was set in relation to heart rate to calculate the stroke flow. A significantly increased D of Sub was found in the racket arm of able-bodied tennis players compared with the opposite arm (19%). Fem of able-bodied road cyclist athletes and of the intact limb in below-knee amputated athletes showed similar increases. D of Fem was lower in athletes with paraplegia (37%) and in below-knee amputated athletes proximal to the lesion (21%) compared with able-bodied, untrained subjects; CS-indexes were reduced 57 and 31%, respectively. Athletes with paraplegia demonstrated a larger D (19%) and a larger CS-index in Sub (54%) than able-bodied, untrained subjects. No significant differences in D and CS-indexes of the thoracic and abdominal aorta were found between any of the groups. The changes measured in Sub and Fem were associated with corresponding alterations in blood flow and stroke flow in all groups. The study suggests that the size and blood flow volume of the proximal limb arteries are adjusted to the metabolic needs of the corresponding extremity musculature and underscore the impact of exercise training or disuse on the structure and the function of the arterial system.

[Effects of physical training and age-induced structural and functional changes in cardiovascular system and skeletal muscles]

Age-related morphological changes in the cardiovascular system refer to a thickening of the arterial wall as well as a diffuse increase in the wall thickness of the myocardium. In terms of function, this leads to a decrease of the myocardial contractility in systole and to a delay of the diastolic myocardial relaxation. At the arterial wall, an impairment of wall elasticity as well as a decrease of the vasoreagibility can be observed. The systolic blood pressure and the blood pressure amplitude rise; the blood flow-dependent vasodilatation mediated by endothelial cells decreases. The loss of cardiac pacemaker cells by approximately 90% from the 2nd to the 8th decade leads to a reduction of the heart rate variability and to a decrease of the maximum heart rate during exhaustive physical exercise. Hemodynamically these changes resulted in a continuous decline of the maximum cardiac output as well as the maximum oxygen transport capacity. Between the 3rd and 8th decade the peripheral skeletal muscle mass decreases as a result of a reduction of the size and the number of muscle fibers with an overproportional loss of 30-40% regarding the highly glycolytic type IIb fibers. Furthermore, the intramuscular capillarization declines so that, with a concomitant decrease in the number and size of the mitochondria, the supply with oxygen and energy sources and consecutively the aerobic muscular energy metabolism decreases by 8-10% per decade beginning with the 4th to 5th decade. Additionally, the maximum and explosive muscular strength decreases by 30-35% from the 4th decade onwards. In older, healthy men who perform a regular aerobic muscular training in endurance sport disciplines (e.g., walking, jogging or cycling), a decrease of the resting heart rate, a restoration of the primarily lowered heart rate variability, an improvement of the early diastolic left-ventricular filling as well as a significant increase in the VO2max could be proven. Other studies showed that regular endurance training on a cycle-ergometer resulted in a significant increase in capillarization within the exercising muscle groups. In older, trained individuals a reduced stiffness of the arterial vessel walls and an improved maximum exercise-induced muscular blood supply occurs. In other training studies performed with older subjects, a positive influence of regular endurance training on the carbohydrate metabolism along with an improvement of the primarily reduced insulin sensitivity could be demonstrated. In older men and women who regularly underwent muscular strength training, a significant increase in maximum strength with a significant increase in the proportion of type II muscle fibers was found.

[Value of training-induced effects on arterial vascular system and skeletal muscles in therapy of NYHA II/III heart failure]

Dynamic muscular exercise performed by healthy subjects leads to a rise in the left ventricular blood ejection with an acute increase in the local wall shear stress on the endothelium of the arterial vessels. These hemodynamic changes results in a release of endothelium-dependent relaxing factors, one of them concerns nitric oxide (NO). Therefore an arterial vasodilatation with an acute increase in the blood flow volume to the exercising muscle groups occurs. If more than 1/6 of the skeletal musculature is involved in exercise and if training duration exceeds 3-5 hours a week the chronically increased blood flow volume in the cardiovascular system triggers structural and functional changes of the heart and the arterial vessels. It develops a functional intact excentric hypertrophy of the myocardium; within the arterial vessels an increase in the diameter of the muscular arteries supplying the trained muscle groups occurs. These training-induced adaptations of the cardiovascular system are adjusted to improve the aerobic skeletal muscle metabolism. In congestive heart failure a pathological excentric myocardial hypertrophy is found. In this case the systolic myocardial function is impaired and the left ventricular ejection fraction is reduced already in early stages, so that the cardiac output can not be sufficiently increased during exercise. In addition a dysfunction of the endothelium of the arterial vessels occurs. As a consequence the endothelium-dependent arterial vasodilation is reduced, so that the peripheral arteries could not supply the muscle groups involved in exercise with enough blood flow volume. Therefore, the acute delivery of the working musculature with oxygen and energy substrates is insufficient, so that premature muscular fatigue occurs. The reduced exercise resistance of the patients leads chronically to a generalized skeletal muscle atrophy. Ultrastructural analysis revealed a decrease of oxidative type 1 muscle fibers with a relative increase of more glycolytic type 2 fibers. In addition, the volume density and the surface area of the cristae of mitochondria are reduced. All these changes results in a decrease of aerobic skeletal muscle metabolism independent of the blood flow volume, so that the physical fitness of the patients progressively decline. On the basis of the training-induced physiological adaptations of the cardiovascular system, a special exercise therapy supervised by a physician was developed for patients with congestive heart failure NYHA II/III. It have been shown that various exercise programs, which are adjusted to the degree of cardiac function impairment are suitable to restore the endothelial dysfunction of the arterial vessels as well as to cure the disturbed skeletal muscle metabolism in these patients independent of an improvement of cardiac function. Therefore in patients with congestive heart failure NYHA II/III who underwent regularly such an exercise therapy, the secondary impaired physical fitness could be rebuild without an excessive risk for an acute exercise-induced cardiovascular emergency.

Development of peak performance in track cycling

BACKGROUND

Retrospective analysis of peak performances can be a usefull tool for the estimation of future trends in high performance sports. The purpose of this study was to investigate the evolution of performance in track cycling from 1979 to 1999 and to asses age- and gender-related differences.

METHODS

We studied the results of the world track cycling championships for this period in 200 m, 1000 m, individual and team pursuit races for elite and junior athletes. Overall trends, performance differences between rank 1 and 5, gender- and age-related differences were calculated.

RESULTS

They show a significant (p<0.01) improvement in 1000 m, individual and team pursuit times for men and individual pursuit times for women. No significant evolution was seen in 200 m performance. In junior riders, only male athletes showed a continuous, significant improvement of average race speed in individual and team pursuit over the study period. Gender difference was 11+/-1.8% in all disciplines at all ages. Difference between elite and junior riders ranged between 5+/-2.1% for male and 6.1+/-2.2% for female athletes. The gap between rank 1 and 5 remained constant (2-3%) over the study period.

CONCLUSIONS

A continuous improvement of performance over the last 20 years is visible in track cycling endurance disciplines. New technical developments show no statistical significant impact. The performance gap between male and female athletes is constant, independent of discipline or race distance and comparable to observations in other sports. Age-related differences in performance is most visible in disciplines requiring short, high intensity power output. Based on these data, estimation of possible winning times and adaptation of training programs for future track cycling competitions might be facilitated.

Urine catecholamine concentrations and psychophysical stress in elite tennis under practice and tournament conditions

BACKGROUND

The purpose of the study was to specify and define the differences of psychophysical stress in elite tennis players under practice and tournament conditions.

METHODS

Basal, pre- and postcompetition urine samples of 26 nationally ranked players (NR) were analysed for concentrations of epinephrine (EPI) and norepinephrine (NE) under practice (P) and tournament conditions (T). Results were completed by the values obtained from two internationally ranked players (IR) competing in 6 (player A) and 5 (player B) Davis-Cup matches, respectively.

RESULTS

In NR, pre- and postcompetition concentrations for EPI were significantly higher under tournament conditions (T: 1.33+/-0.65 and 3.66+/-2.51 microg/100 mg creatinine vs P: 0.61+/-0.39 and 0.97+/-0.59 microg/100 mg creatinine). The NE/EPI ratio showed significantly inverse results (T: 3.53+/-1.87 and 3.58+/-1.59 vs P: 8.08+/-6.99 and 10.03+/-6.58), whereas the concentration of NE did not differ between the two conditions. Significant correlations were found between the level of perceived nervousness (ten-point-likert scale) and the postcompetition concentration of EPI (r=0.491, p<0.05) and the NE/EPI ratio (r=-0.595, p<0.01). Players who felt affected by nervousness in their performance outcome showed significantly lower NE/EPI ratios (2.73+/-1.44 vs 4.49+/-2.54, p<0.05). The Davis-Cup-Players showed intra-individually constant but inter-individually different concentrations of EPI (A= 2.2+/-0.5 vs B= 7.0+/-0.8 microg/100 mg creatinine), NE (A= 7.4+/-2.2 vs B= 15.5+/-3.2 microg/100 mg creatinine) and the ratio of NE/EPI (A= 3.7+/-2.2 vs B= 2.2+/-0.7).

CONCLUSIONS

In tennis tournaments, sympathetic activity is increased due to a higher psychological stress which may impair performance. Practical efforts should focus on psycho-regulative methods and psychophysical regeneration for players dealing with a chronic sympathetic hyper-activation.

Fluvastatin lowers atherogenic dense low-density lipoproteins in postmenopausal women with the atherogenic lipoprotein phenotype

BACKGROUND

Although HMG-CoA reductase inhibitors (HMGRIs) are effective lipid-lowering agents, it remains controversial whether these agents also lower dense LDL (dLDL), a predominance of which is considered to contribute to the atherogenicity of the metabolic syndrome.

METHODS AND RESULTS

In a multicenter, double-blind, randomized, placebo-controlled study, we determined the effect of the HMGRI fluvastatin on lipids, apolipoproteins, and LDL subfractions (by equilibrium density gradient ultracentrifugation). A total of 52 postmenopausal women with combined hyperlipidemia and increased dLDL were treated with either fluvastatin 40 mg/d (n=35) or placebo (n=17). After 12 weeks' treatment, significant reductions (P<0.001) in total cholesterol (-19%), IDL cholesterol (-35%), LDL cholesterol (-23%), apolipoprotein B (-21%), and apolipoprotein B in dLDL (-42%) were apparent among fluvastatin recipients. No significant changes in triglycerides or HDL cholesterol were observed. The effect of fluvastatin on dLDL was correlated with baseline values. There was no consistent relationship, however, between the effect of fluvastatin on triglycerides and the decrease in dLDL.

CONCLUSIONS

Fluvastatin lowers total and LDL cholesterol and the concentration of dLDL. This profile may contribute to an antiatherogenic effect for fluvastatin that is greater than expected on the basis of changes in lipids and apolipoproteins.

Cardiovascular, metabolic, and hormonal parameters in professional tennis players

During the past decade, the physical and mental stress in professional tennis has been constantly increasing. The overall intensity in tennis ranges between 60 and 70% of maximum oxygen uptake and the energy requirements are mainly provided by aerobic energy metabolism. Therefore, particularly with respect to the duration of the tournaments and the length of the matches, a good aerobic capacity promotes continuous success in professional tennis. During frequent periods of high intensity, however, muscular energy is derived from anaerobic glycolysis. Therefore, sports-specific conditioning programs in tennis should improve both glycolytic and oxidative muscular metabolism. Years of training and competition induce a number of cardiovascular and metabolic adaptations: an increase in heart size in terms of an athlete's heart, higher oxygen uptake capacity, improved muscular oxidative enzyme activities, reduced baseline catecholamine levels, and a lower resting heart rate. In addition, tennis induces side-specific increments in bone density, bone diameter, and bone length of the upper extremity. Furthermore, structural and functional adaptations of the conducting arteries in the preferred arm could be demonstrated in professional tennis players. In conclusion, tennis is a very complex sport involving strength, power, speed, agility and explosiveness, as well as endurance components. Scientific data on exercise-related cardiovascular and metabolic parameters in professional tennis are important to evaluate the players individual fitness level and will help to improve sports-specific conditioning programs. This in turn will not only enhance performance but also prevent overstrain and burnout syndromes.

Patients with fibromyalgia benefit from aerobic endurance exercise

Fibromyalgia (FM) is a disorder characterised by diffuse widespread musculoskeletal aching and stiffness and multiple tender points [1]. Its pathophysiology is poorly understood. The influence of aerobic endurance exercise on pain in patients with FM was investigated. Twenty-seven patients (25 female, 2 male) participated in a controlled clinical study and performed 12 weeks of jogging, walking, cycling or swimming following a given schedule. Twelve sedentary FM patients (11 female, 1 male) served as controls. Before and after training both the study and the control groups were evaluated spiroergometrically. Tender point pain was quantified by dolorimetry. The painful body surface was estimated by a pain body diagram, and its intensity by a visual analogue scale and a ranking scale. Patients trained for an average of 25 min two to three times a week, with an average intensity of 50% of maximal oxygen uptake (VO2max). Unlike the control group, the training group exhibited a decrease in heart rate and VO2 and an increase in respiratory quotient during submaximal workload. Maximal performance capacity and VO2max remained unchanged, whereas the wattpulse (watt/heart rate) improved at maximal workload. Pain parameters remained unchanged in the control group, but in the training group the mean number of positive tender points (15.4/12.7), the mean pain threshold of the gluteal tender point (2.89 kp/3.50 kp) and the painful body surface (18%/15% body surface) decreased significantly. Subjective general pain condition deteriorated in two patients but improved in 17. Our results suggest a positive effect of aerobic endurance exercise on fitness and well-being in patients with FM.

Left ventricular wall motion during diastolic filling in endurance-trained athletes

PURPOSE

The purpose of this study was to assess left ventricular (LV) wall motion in highly endurance-trained athletes to evaluate LV diastolic function in physiologically hypertrophied hearts.

BACKGROUND

Diastolic filling dynamics have previously been examined in endurance-trained athletes by measuring pulsed-wave mitral inflow velocities during the early and atrial filling phase, indicating an unimpaired LV function. Assessment of LV wall motion may give additional information about the LV diastolic function in endurance-trained athletes.

METHODS

Left ventricular mass (LVM) and volume (LVV) were determined by M-mode echocardiography. Peak LV wall motion in the region of the basal septum close to the mitral anulus were measured during the early rapid and atrial filling phase by tissue Doppler in 30 endurance-trained athletes (T) and 16 sedentary control subjects (C) presumed to be healthy.

RESULTS

Myocardial LVM and LVV in T (LVM 159.4 +/- 18.0 g.m(-2), LVV 100.4 +/- 13.0 mL.m(-2)) were significantly higher than in C (LVM 105.7 +/- 12.0.m(-2), LVV 70.1 +/- 11.9 mL.m(-2)), and heart rate (HR) was significantly lower (HR C: 69.6 +/- 11.0 bpm, T 50.9 +/- 8.7 bpm),which is consistent with endurance training (P < 0.01 for both). Peak LV wall motion during the early rapid filling phase did not differ significantly between the groups (T: 10.69 +/- 1.46 cm.(s-)1; C: 10.61 +/- 1.52 cm.(s-)1). Peak atrial wall motion was significantly lower in T (4.53 +/- 0.84 cm.s-1) versus C (5.74 +/- 0.75 cm.s(-1)), and the ratio of peak early diastolic to atrial wall motion was consequently higher in athletes (P < 0.01 for both).

CONCLUSION

Regional wall motion at the basal septum near the mitral anulus during the early rapid filling phase is not altered by an increase in LVM or LVV when associated with endurance training.

Catecholamines response of high performance wheelchair athletes at rest and during exercise with autonomic dysreflexia

Autonomic dysreflexia presents a special situation in high-lesion spinal cord injury, however, intentionally or self-induced autonomic dysreflexia directly before or during competition to increase performance, so called 'boosting', is also being reported. In order to examine the influence of autonomic dysreflexia on plasma catecholamines, cardiocirculatory and metabolic parameters, 6 spinal cord injured wheelchair athletes with high-level lesions underwent wheelchair ergometry without (ST1) and with (ST2) autonomic dysreflexia. At the point of exhaustion significantly higher values for norepinephrine and epinephrine were observed in ST2 than in ST1. During autonomic dysreflexia a significantly higher peak performance (77.5 vs. 72.5 watt), higher peak heart rate (161 vs. 149 x min(-1)), and peak oxygen consumption (1.96 vs. 1.85 l x min(-1)), with comparable peak lactate (7.11 vs. 7.00 mmol x l(-1)) were reached on average. The blood pressure values in ST2 were partially hypertensive and higher than in ST1. In conclusion, autonomic dysreflexia, as a sympathetic spinal reflex, leads to a higher release of catecholamines during exercise. This results in higher peak performance, peak heart rate, peak oxygen consumption, and higher blood pressure values. The peak lactate, as an indicator of the anaerobic lactate metabolism, was unchanged. However, autonomic dysreflexia presents an unpredictable risk, caused predominantly by hypertensive blood pressure values, for high-lesion spinal cord injured persons at rest and more so during exercise; it is seen as a prohibited manipulation by the doping guidelines of the International Paralympic Committee.

Arterial properties of the carotid and femoral artery in endurance-trained and paraplegic subjects

In humans, the relationships of blood flow changes to structure, function, and shear rate of conducting arteries have not been thoroughly examined. Therefore, the purpose of this study was to investigate these parameters of the elastic-type, common carotid artery (CCA) and the muscular-type, common femoral artery (CFA) in long-term highly active and extremely inactive individuals, assuming that the impact of activity-induced blood flow changes on conduit arteries, if any, should be seen in these subjects. We examined 21 highly endurance-trained athletes (A), 10 paraplegic subjects (P), and 20 sedentary subjects (S) by means of noninvasive ultrasound. As a result, the CFA diameter and compliance were highest in A (9.7+/-0.81 mm; 1.84 +/-0.54 mm(2)/kPa) and lowest in P (5.9+/-0.7 mm; 0.54+/-0.27 mm(2)/kPa) compared with S (8.3+/-1.0 mm; 0.92+/-0.48 mm(2)/kPa) with P <0.01 among the groups. Both parameters correlated with each other (r = 0.62; P<0.01). Compared with A (378+/-84 s(-1); 37+/-15 s(-1)) and S (356+/-113 s(-1); 36+/-20 s(-1)), the peak and mean shear rates of the CFA were almost or more than doubled in P (588+/-120 s(-1); 89+/-26 s(-1)). In the CCA, only the compliance and peak shear rate showed significant differences among the groups (A: 1.28+/-0.47 mm(2)/kPa, 660+/-138 s(-1); S: 1.04+/-0.27 mm(2)/kPa, 588+/-109 s(-1); P: 0.65+/- 0.22 mm(2)/kPa, 490+/-149 s(-1); P<0.05). In conclusion, the results suggest a structural and functional adaptation in the CFA and a predominantly functional adaptation of the arterial wall properties to differences in the physical activity level and associated exercise-induced blood flow changes in the CCA. The results for humans confirm those from animal experiments. Similar shear rate values of S and P in the CFA support the hypothesis of constant shear stress regulation due to local blood flow changes in humans. On the other hand, the increased shear rate in the CFA in P indicates an at least partially nonphysiological response of the arterial wall in long-term chronic sympathectomy due to a change in local blood flow.

A polymorphism in the alpha2a-adrenoceptor gene and endurance athlete status

PURPOSE

In a case control study, we examined the allelic frequencies and genotype distributions of two restricted fragment length polymorphisms (RFLP) in the alpha-2A-adrenoceptor gene (ADRA2A) and beta-2-adrenoceptor gene (ADRB2) among elite endurance athletes (EEA) and sedentary controls (SC).

METHODS

The EEA group included 148 Caucasian male subjects recruited on the basis that they had a VO2max > 74 mL O2 x kg(-1) x min(-1). The SC group comprised 149 unrelated sedentary male subjects, all Caucasians, from the Quebec Family Study. After digestion with the restriction enzymes Dra I (ADRA2A) and Ban I (ADRB2), Southern blotting and hybridization techniques were used to detect the mutations in the two ADR genes, which are encoded on chromosomes 10 (q24-26) and 5 (q31-32), respectively.

RESULTS

For the Dra I ADRA2A RFLP, we observed a significant difference in genotype distributions between the two groups (P = 0.037). A higher frequency of the 6.7-kb allele was observed in the EEA group compared with the SC group (P = 0.013). No statistically significant difference was found between groups for the Ban I ADRB2 polymorphic site. Genotype frequencies for both genes in both groups were in Hardy-Weinberg equilibrium.

CONCLUSIONS

In summary, we found evidence that ADRA2A gene variability detected with Dra I is weakly associated with elite endurance athlete status, and we conclude that genetic variation in the ADRA2A gene or a locus in close proximity may play a role in being able to sustain the endurance training regimen necessary to attain a high level of maximal aerobic power.

[The Freiburg Intervention Trial for Obesity in Chidren (FITOC)]

Freiburg Intervention Trial for Obese Children (FITOC) is an interdisciplinary treatment program for obese children, which is established in Freiburg since 1987. Obese children at the age of 8-11 are treated in an eight months intensive period and a follow-up period of 4 months or more. Since 1990 data from 283 children coming out of 15 treatment groups (about 2 groups per year) were collected and analyzed. The program consists of regular physical training (3 times a week), comprehensive nutrition and behaviour training (overall 7 parents evenings each 4 to 6 weeks and 7 cookery courses for the kids in the same time scale). The parents evenings are filled with theoretical and practical information about nutrition as well as background information about the psychological and physiological problems in obese children. In the first examination and the regular control examinations anthropometric, biochemical and exercise physiology data are investigated. In addition, questionnaires for nutrition and behaviour are analysed on a regular basis. At each examination, depending on the progress in therapy, a new orientation with adapted goals will be discussed with the child and the parents. For the growing children a moderate reduction or long term stabilisation of weight will lead to success. Teaching goal for the children in the intensive period is to control themselves and, depending on their specific situation, to establish individual recommendations on a long term basis. The sports program should lead to an increase in self-esteem and a raise in daily energy expenditure. The team includes a physician, a nutritionist, a psychologist and a sports teacher. From 1997 the program was spread to institutions in the surroundings of Freiburg. Training for the external teams is provided for in continuous seminars. Teaching material includes a manual, forms and transparencies. The major goal is to secure quality by continuous training and close interaction between the institutions. Till now the program is performed by a couple of multiplication groups in different regions of Germany. First data analysis has shown that the out-patient program is transferable and comparable results are reachable after a standardized training course for the included therapists. The plan for 2000 and 2001 is to increase the number of centers involved to a total of 20 all over Germany.

Lipoproteins and free plasma catecholamines in spinal cord injured men with different injury levels

Persons with spinal cord injury (SCI) are especially prone to atherogenesis. This is partly explained by an unfavourable lipoprotein profile in these individuals. The impairment of the sympathetic nervous system, and the fact that SCI subjects are subject to extreme physical inactivity, may have an influence on their lipid profile and lipoprotein(a) concentration. We made a detailed investigation of the lipid profile as well as serum levels of adrenaline and noradrenaline in 80 men with SCI ranging from tetraplegia to low paraplegia and in 16 control subjects. The lipid profile of tetraplegics was characterized by elevated very low-density lipoprotein cholesterol and triglyceride levels and reduced high-density lipoprotein levels. In contrast, paraplegics had significantly higher low-density lipoprotein and total cholesterol levels. Tetraplegics had lower and the low-lesion paraplegics had higher adrenaline and noradrenaline levels than the high-lesion paraplegics and the control subjects. High-lesion SCI subjects also showed an extreme reduction in VO2max. The lipoprotein profile was dependent on the injury level and serum catecholamine concentrations. The lower the noradrenaline values, the lower the high-density lipoprotein cholesterol. The low-density lipoprotein also correlated to catecholamines and particularly adrenaline values. Despite the correlation between lipoprotein(a) and adrenaline, no significant differences in lipoprotein(a) were found within SCI individuals as well as between SCI individuals and control subjects, indicating the predominantly genetic determination of lipoprotein(a) and thus the cardiovascular risk. Different serum catecholamine levels due to impairment of sympathetic nervous system and VO2max levels were observed in SCI subjects. This was associated with a higher lipid risk profile for cardiovascular diseases; however, the risk profile is dependent on the lesion level.

Haemoglobin, haematocrit and red blood cell indices in elite cyclists. Are the control values for blood testing valid?

BACKGROUND

In international cycling and cross-country skiing competitions, blood tests are used to unmask the performance enhancing misuse of erythropoietin. Haematocrit (cycling) and haemoglobin (cross-country skiing) limits have been set by international sporting federations (haematocrit 50%, haemoglobin 18.5 g/dl). Athletes tested above these cut-off values are declared unfit for competition. To investigate the validity of these regulations, we studied haemoglobin, haematocrit and red blood cell indices of elite cyclists before erythropoietin became commercially available.

MATERIAL AND METHODS

We investigated 523 blood samples of 92 male elite cyclists (age 16-31 years) from 1978 to 1987. Haematocrit, haemoglobin and red blood cell count were analysed automatically, erythrocyte indices were calculated.

RESULTS

Haemoglobin (-0.3 +/- 1 g/dl), haematocrit (-1.2 +/- 2.8%) and red blood cell count (-0.2 +/- 0.4 x 10(6)/mm3) decreased significantly (p < 0.05) with increasing training workload. The erythrocyte indices showed no significant change. Fifty-four blood samples (10.3%) showed a haematocrit above 50%, one sample presented a haemoglobin mass higher than 18.5 g/dl. During periods of increased workload, less athletes tested above the haematocrit limit.

CONCLUSION

The current haematocrit limit used in blood tests might lead to a high number of false positive tests.

No association between the angiotensin-converting enzyme ID polymorphism and elite endurance athlete status

Several studies have reported that the insertion (I) allele of the angiotensin-converting enzyme (ACE) I/deletion (D) polymorphism is associated with enhanced responsiveness to endurance training and is more common in endurance athletes than in sedentary controls. We tested the latter hypothesis in a cohort of 192 male endurance athletes with maximal oxygen uptake >/=75 ml. kg(-1). min(-1) and 189 sedentary male controls. The ACE ID polymorphism in intron 16 was typed with the three-primer polymerase chain reaction method. Both the genotype (P = 0.214) and allele (P = 0.095) frequencies were similar in the athletes and the controls. Further analyses in the athletes revealed no excess of the I allele among the athletes within the highest quartile (> 80 ml. kg(-1). min(-1)) or decile (>83 ml. kg(-1). min(-1)) of maximal oxygen uptake. These data from the GENATHLETE cohort do not support the hypothesis that the ACE ID polymorphism is associated with a higher cardiorespiratory endurance performance level.

Assessment of arterial blood flow characteristics in normal and atherosclerotic vessels with the fast Fourier flow method

The purpose of this study was to scrutinize the ability of magnetic resonance imaging (MRI)-performed measurements to compare arterial flow patterns in patients with peripheral arterial occlusive disease (PAOD), healthy volunteers (HV) and endurance athletes (EA). MRI blood flow data were partially repeated with Doppler ultrasound (DUS) with a view to a methodical comparison. Additionally, pulse wave velocity was assessed with the MUFF technique. For this purpose, MRI-performed flow measurements were performed in the common femoral artery in 21 patients with PAOD, in 34 HV and in 12 EA. The analysis included maximum flow velocities (MFV), velocity/time profile (VTP), pulse wave velocity (Vpulse), and vessel diameter (VD). In addition, MFV and VD were observed by DUS in most individuals. The results revealed a significant change regarding arterial blood flow characteristics in patients compared with HV and EA, with respect to the span between the peak positive and negative blood flow velocity in the femoral artery. The pulse wave velocity in patients was markedly elevated compared with healthy individuals. Furthermore, a complete, characteristic change in the VTP could be observed in patients. The methodical comparison between DUS and MRI showed a good correlation. Multi-slice Fourier flow data have indicated markedly increased pulse wave velocity in PAOD patients. Changes in the arterial blood flow can be clearly observed with MRI. In the future, this might offer a noninvasive possibility not only for the evaluation of the stage of the disease, but also for the detection of early, pre-clinical stages of atherosclerosis.

Association of physical fitness with LDL and HDL subfractions in young healthy men

A dyslipoproteinemia of increased concentrations of small, dense LDL particles and reduced HDL2 cholesterol has shown to be associated with coronary heart disease (CHD). In contrast, an increase in physical fitness and a reduction of body mass index (BMI) improve the lipoprotein profile and reduce the incidence of cardiovascular events. The association of physical exercise, physical fitness, and body weight with an atherogenic lipoprotein subfraction profile has been investigated before in obese subjects, but the relationship is unknown in a healthy non-obese population without insulin resistance or CHD. Therefore, a detailed lipoprotein subfraction profile of 3 HDL and 6 LDL subfractions was determined in 125 healthy men (26+/-5 years). Physical fitness (maximal oxygen consumption, VO2max) was assessed by ergometry and physical activity by questionnaire. Those men with the lowest physical fitness (VO2max < 40 ml/kg/min) and the lowest physical activity score had a significantly less favourable lipoprotein subfraction profile of increased concentration of small, dense LDL particles (d: > 1.044 g/ml) and reduced HDL2a cholesterol than those with a VO2max >50 ml/kg/min. Multivariate regression analysis revealed that concentrations of small, dense LDL particles were primarily determined by BMI whereas HDL2a cholesterol and apolipoprotein A-I were primarily determined by physical fitness. These findings underline the relationship between a good physical fitness, a low body weight, and a favourable lipoprotein subfraction profile even in a healthy young male population.

Concurrent reductions of serum leptin and lipids during weight loss in obese men with type II diabetes

The aim of the study was to examine the effects of weight reduction by exercise and diet on metabolic control in obese subjects with insulin resistance, particularly investigating if changes in serum leptin concentrations were directly associated with improvements in metabolic control. Twenty obese men (48 +/- 8 yr; body mass index 32. 1 +/- 3.9 kg/m(2)) with previously diagnosed type II diabetes mellitus were assigned to a 4-wk intervention program of exercise (2, 200 kcal/wk) and diet (1,000 kcal/day; 50% carbohydrates, 25% protein, 25% fat; polyunsaturated-to-saturated fatty acid ratio 1.0). Intervention induced significant reductions in body weight and serum leptin levels, and improvements in lipoprotein profile and glucose control. Reductions in leptin levels were directly associated with reductions in serum triglycerides and cholesterol, a finding that was independent of improvements in glucose control. These data show that serum leptin concentrations can be reduced with caloric restriction and exercise in male patients with type II diabetes, and they suggest a direct relationship between leptin and lipoprotein metabolism that is not solely due to weight reduction.

QT dispersion in exercise-induced myocardial hypertrophy

BACKGROUND

The measurement of QT dispersion in the surface electrocardiogram is a noninvasive method used for assessing inhomogeneity of myocardial repolarization. Elevated QT dispersion is found in myocardial disease and is associated with an increased incidence of arrhythmic events. QT dispersion is also increased in myocardial hypertrophy secondary to systemic hypertension. However, the relation between left ventricular (LV) enlargement in endurance trained subjects and QT dispersion is unknown.

METHODS AND RESULTS

In this study, LV mass (2-dimensional echocardiography) and QT dispersion (12-lead resting electrocardiogram) were assessed in 26 normotensive endurance trained subjects and 26 matched, less trained control subjects. Endurance trained subjects had a significantly greater LV mass (216 +/- 39 g vs 155 +/- 30 g, P <.001) but lower heart rate-corrected QTc dispersion (42 +/- 13 ms vs 51 +/- 15 ms, P =.012) than less trained control subjects. When all individuals were included, LV mass was inversely correlated with QT dispersion (r = -0.38; P =.002) and heart rate-corrected QTc dispersion (r = -0.53, P <.0001).

CONCLUSIONS

These data show that myocardial hypertrophy induced by exercise training is not associated with increased QT dispersion as observed in systemic hypertension. The reduced QT dispersion reflects homogeneous myocardial repolarization and may help to explain the reduced mortality rate in regularly exercising subjects. If confirmed in further studies, the measurement of QT dispersion could provide a simple and inexpensive screening method for differentiating between physiologic and pathologic myocardial hypertrophy.

[Freiburg Questionnaire of physical activity--development, evaluation and application]

Aim of the present study was to design a questionnaire to assess health related physical activity, to validate the instrument and to apply it to a population sample. Reliability of the questionnaire was evaluated by test-retest investigations with intervals of two weeks and six months. High correlations between the repeated administrations reflect a good reliability of our instrument. Only gardening and cycling, as well as the depending basic and total activity, showed typically seasonal variations. Validity was established by correlating physical activity data with maximum oxygen uptake. Maximum oxygen uptake correlated with sport activities (partial correlation coefficient: r = 0.422, p < 0.01). Evaluated data were consistent. People rating themselves as "more active than their coevals" were indeed more active in sport (r = 0.334, p < 0.01) and total activity (r = 0.282, p < 0.05). Studying activity patterns of a population sample of adult residents of Freiburg (systematic random sampling, n = 612, 20-98 years) we found total physical activity of 9.2 hours per week (median), with activities of low to moderate intensities dominating. Age and gender are important determinants of the activity patterns. According to the recommendation of Paffenbarger (2000 kcal/week total physical activity) 40% of the residents of Freiburg did not reach the recommended energy expenditure. Compared to the recommendation of the American College of Sports Medicine (1000 kcal/week by training) 63% of the population sample were not active enough.

Relation of leisure-time physical activity to structural and functional arterial properties of the common carotid artery in male subjects

The structure and function of central arteries are altered with advancing age. These changes comprise arterial dilation, intima-media thickening and increase in stiffness. Arterial wall hypertrophy and increased stiffness are associated with major cardiovascular disease. In contrast to this, physical activity has been found to be inversely related to the incidence of major cardiovascular disease and mortality in humans. However, conflicting data exist on the effect of physical activity on arterial stiffness and very little data about its association with structural arterial properties. We therefore investigated the association of the self-selected leisure-time physical activity (LTPA), assessed by a self-administered questionnaire, with the structure and function of the common carotid artery, examined with high-resolution ultrasound, in 51 male subjects aged between 16 and 78 years. We found that men with a higher level of LTPA (> 38.1 MET*h/week = H-LTPA) (metabolic equivalent value; 1 MET= energy expended by a person at rest, i.e. approximately 3.5 ml oxygen uptake/kg body mass or 1 kcal/kg per h) had a significantly lower arterial stiffness (P = 0.02) than men with lower levels ( < 38.1 MET*h/week = L-LTPA) (4.32+/-1.17 versus 5.75+/-1.21 x 10(6) cm(-2)). In multiple regression analyses, with several atherosclerotic risk factors as correlating variables with arterial stiffness, LTPA persisted as an independent predictor of arterial stiffness (adjusted R2=0.19) in addition to apolipoprotein B level (adjusted R2 = 0.33). The study could not, however, show an association of LTPA with reduced intima-media thickness (L-LTPA = 0.66+/-0.15 versus H-LTPA 0.66+/-0.14) or arterial dilation of diastolic diameter (L-LTPA = 6.34 + 0.64 versus H-LTPA 6.08+/-0.69). However, the positive association of LTPA with several parameters, which correlated inversely with intima-media thickness, may be taken as an indicator for a possible positive (not visible in an ultrasonic examination of the common carotid artery) effect of LTPA on the arterial wall structure.

Effects of physical activity on the fatigue and psychologic status of cancer patients during chemotherapy

BACKGROUND

Fatigue is a common and often severe problem in cancer patients undergoing chemotherapy. The authors postulated that physical activity training can reduce the intensity of fatigue in this group of patients.

METHODS

A group of cancer patients receiving high dose chemotherapy followed by autologous peripheral blood stem cell transplantation (training group; n = 27) followed an exercise program during hospitalization. The program was comprised of biking on an ergometer in the supine position following an interval training pattern for 30 minutes daily. Patients in the control group (n = 32) did not train. Psychologic distress was assessed at hospital admission and discharge with the Profile of Mood States and Symptom Check List 90.

RESULTS

By the time of hospital discharge, fatigue and somatic complaints had increased significantly in the control group (P for both < 0.01) but not in the training group. Furthermore, by the time of hospital discharge, the training group had a significant improvement in several scores of psychologic distress (obsessive-compulsive traits, fear, interpersonal sensitivity, and phobic anxiety) (P value for all scores < 0.05); this outcome was not observed in the control group.

CONCLUSIONS

The current study found that aerobic exercise can reduce fatigue and improve psychologic distress in cancer patients undergoing chemotherapy.

Effectiveness of digitoxin versus trichlormethiazide/amiloride in congestive heart failure NYHA class II/III and sinus rhythm

The effects of digitoxin and/or diuretic agents were investigated in patients with congestive heart failure (CHF) in sinus rhythm with respect to changes in hemodynamic parameters, cardiac dimensions, and bicycle ergometric exercise capacity. In a randomized, double-blind study 16 male patients with CHF NYHA class II and III received a placebo for 1 week (baseline) and then were randomly allocated, double blind, to take either digitoxin (digitalis group, DI: N = 8) or trichlormethiazide/amiloride (diuretic group, DG: N = 8) for 3 weeks (VP I). The patients who were first treated with digitoxin received the diuretic agent for a further 3 weeks and vice versa (VP II). At baseline and after VP I and II, a physical examination, two-dimensional echocardiography, and bicycle ergometry were performed. Heart rate (HR), systolic (BPs), and diastolic (BPd) blood pressure at rest, and BPs and 50 watts, were not significantly changed during the observation period. HR at 50 watts was decreased in DI (11.5 +/- 10.1 beats/min.) after VP I and II, but not in DG. BPd was significantly reduced after VP II in DI (8.2 +/- 4.6 mmHg) and in DG (9.3 +/- 8.9 mmHg). DI presents at baseline significantly higher end-diastolic (LVEDV) and end-systolic (LVESV) left ventricular dimensions, whereas left atrial diameter (LA) and stroke volume (SV) and ejection fraction (LVEF) were not significantly different. After VP I, a significantly decreased LA was found in DI, but not in DG. After VP II, all cardiac dimensions were significantly reduced compared with the baseline in DI, whereas in DG only a decrease in LVESV was found. SV was significantly increased in DI, but not in DG after VP I, SV and LVEF were significantly improved in DI and in DG after VP II. Exercise capacity did not change significantly in DI and DG. Digitoxin in combination with trichlormethiazide/amiloride is effective in reducing primarily enlarged left atrial and left ventricular dimensions, and is sufficient to improve the impaired systolic left ventricular function in CHF of NYHA class II and III in sinus rhythm. However, a significant increase in exercise capacity was not found. Treatment with digitoxin seems to be more relevant as a monotherapy with trichlormethiazide/amiloride.

Cardiac function and haemodynamics in alcoholic cirrhosis and effects of the transjugular intrahepatic portosystemic stent shunt

BACKGROUND

A portosystemic stent shunt may impair cardiac function and haemodynamics.

AIMS

To investigate the effects of a transjugular intrahepatic portosystemic shunt (TIPS) on cardiac function and pulmonary and systemic circulation in patients with alcoholic cirrhosis.

PATIENTS/METHODS

17 patients with alcoholic cirrhosis and recent variceal bleeding were evaluated by echocardiography and catheterisation of the splanchnic and pulmonary circulation before and after TIPS. The period of catheter measurement was extended to nine hours in nine of the patients. The portal vein was investigated by Doppler ultrasound before and nine hours after TIPS.

RESULTS

Baseline echocardiography showed the left atrial diameter to be slightly increased and the left ventricular volume to be in the upper normal range. Nine hours after TIPS, the left atrial diameter and left ventricular end diastolic volume were increased (by 6% (p<0.01) and 7% (p<0.01) respectively); end systolic volume had not changed significantly. Invasive measurements showed a sharp increase in right atrial pressure (by 101%; p<0.01), mean pulmonary artery pressure (by 92%; p<0.01), pulmonary capillary wedge pressure (by 111%; p<0.01), and cardiac output (8.1 (1.6) to 11.9 (2.4) l/min; p<0.01). Systemic vascular resistance decreased (824 (242) to 600 (265) dyn.s.cm-5 p<0.01), and total pulmonary resistance increased (140 (58.5) to 188 (69.5) dyn.s.cm-5; p<0.05). Total pulmonary resistance (12%; NS), cardiac output (1.4 l/min; p<0. 05), and portal vein blood flow (1.4 l/min; p<0.05) remained elevated for nine hours after TIPS in the subgroup. Portoatrial pressure gradient (43%; p<0.05), portohepatic vascular resistance (72%; p<0.05), and systemic vascular resistance (27%; p<0.01) were consistently reduced.

CONCLUSIONS

The increase in the left atrial diameter, the pulmonary capillary wedge pressure, and total pulmonary resistance observed after the TIPS procedure reflected diastolic dysfunction of the hyperdynamic left ventricle in patients with alcoholic cirrhosis. The haemodynamic effects of the portosystemic stent shunt itself on the splanchnic circulation seem to be mainly responsible for the further decrease in systemic vascular resistance. TIPS may unmask a coexisting preclinical cardiomyopathy in patients with alcoholic cirrhosis and portal hypertension.

Influence of 4 weeks' intervention by exercise and diet on low-density lipoprotein subfractions in obese men with type 2 diabetes

Insulin resistance is associated with dyslipoproteinemia characterized by increased serum triglycerides, reduced high-density lipoprotein 2 (HDL2) cholesterol, and increased small, dense low-density lipoprotein (LDL) subfraction particles. Physical activity and weight reduction are known to improve insulin resistance and dyslipoproteinemia, but their influence on LDL subfractions in diabetic patients is unknown. Therefore, we investigated the effect of a 4-week intervention program of exercise (2,200 kcal/wk) and diet (1,000 kcal/d: 50% carbohydrate, 25% protein, and 25% fat; polyunsaturated/saturated fat ratio, 1.0) on glycemic control and HDL and LDL subfractions in 34 obese patients with non-insulin-dependent diabetes (age, 49 +/- 9 years; body mass index [BMI], 33.1 +/- 5.1 kg/m2). Reductions in body weight (P < .001) and improvements in fasting blood glucose, insulin, fructosamine (P < .001), and free fatty acids (P < .01) by intervention were associated with reductions in serum cholesterol and apolipoprotein B (apo B) concentrations in very-low-density lipoprotein (VLDL) (P < .01), intermediate-density lipoprotein (IDL), and small, dense (>1.040 g/mL) LDL particles (P < .001). These data underlie the positive influence of weight reduction induced by exercise and diet on insulin resistance and lipoprotein metabolism in obese diabetic patients, particularly showing improvements of the LDL subfraction profile with a decrease of small, dense LDL particles. This is of particular importance, as these particles have been shown to be associated with coronary artery disease.

Haemodynamic effects of intracoronary pyruvate in patients with congestive heart failure: an open study

BACKGROUND

Pyruvate, as an intermediate in the Krebs cycle, is an important source of energy for myocardium and improves contractility of normal, hypoxic, and postischaemic animal myocardium. We investigated the effect of intracoronary pyruvate in patients with congestive heart failure.

METHODS

Haemodynamic measurements were done in eight patients with dilated cardiomyopathy after two 15 min infusions of pyruvate into the left main coronary artery and after saline washout of pyruvate.

FINDINGS

There were no significant differences between the two pyruvate concentrations. Application of pyruvate resulted in a 23% increase in cardiac index (p<0.05), a 38% increase in stroke-volume index (p<0.05), and a 36% decrease in pulmonary capillary wedge pressure (p<0.05). Heart rate decreased significantly by 11%. Mean aortic pressure and systemic vascular resistance did not change. Most of the effects of pyruvate were reversed 15 min after the infusion stopped.

INTERPRETATION

Pyruvate has the profile of a favourable inotropic substance. Other modes of administration need to be studied.

[Effect if 6-week nutritional intervention with enzymatic yeast cells and antioxidants on exercise stress and antioxidant status]

The aim of the present study was to investigate the influence of a yeast cell preparation rich in antioxidant vitamins, antioxidant enzymes, trace elements and minerals on the exercise-induced stress reaction and antioxidant status. The study was carried out in a non-blinded, controlled design. After a 6 week pre-ingestion period, 9 highly endurance-trained athletes took the preparation twice daily for another 6 weeks. After each phase venous blood samples were drawn in the resting state after an overnight fast followed by a strenuous 15 km cross country race. 1 h after the exercise venous blood sampling was repeated. Compared to the pre-ingestion period, the following significant alterations could be detected after 6 weeks of ingestion: 1) In the resting state, soluble interleukin-2 receptor (p < 0.05) and plasma fibrinogen (p < 0.01) were shown to be lower whereas plasma fibronectin was increased (p < 0.01). 2) 1 h after the race the significant difference in fibrinogen and fibronectin was confirmed. In addition myoglobin (p < 0.01) and CKMM3 (p < 0.05) as well as mangan superoxid dismutase (p < 0.05) were reduced. In conclusion, the 6-week ingestion-period resulted in an improvement of the systemic and muscular stress reaction. In addition, the decrease in mangan superoxide dismutase concentration can be interpreted as a sign of reduced free radical stress. However, these preliminary results have to be confirmed in larger trials in blinded designs. In addition, there seems to be a rationale for testing the effects of yeast-cell preparations in patients with chronic degenerative diseases as some of the investigated parameters are involved in the pathophysiology of such illnesses.

Structural, functional, and hemodynamic changes of the common carotid artery with age in male subjects

Aging of the common carotid artery (CCA) is associated with different principal structural, functional, and hemodynamic changes, which are often influenced by several atherosclerotic risk factors, so that it is difficult to estimate the exclusive effect of aging on this process. Studies dealing with vascular aging of the CCA usually assess only single, dimensional, or functional parameters, although it is likely that there are interactions and probably differences between them. Moreover, regional vascular blood flow characteristics are often not taken into consideration. Therefore, the aim of the study was to assess the age-related multiparametric changes of the CCA properties with ultrasound in 69 male subjects between the ages of 16 and 75 (42.4+/-16.5 years), who were screened for the absence of major atherosclerotic risk factors or existing vascular disease. As a result, the intima media thickness (0.052 mm/10 y) and diastolic diameter (0.17 mm/10 y) increased nearly linearly with age (r=0.60, P<0.001; and r=0.46, P<0.001, respectively). The absolute diastolic/systolic diameter change diminished by 0.10 mm/10 y (r=-0. 73, P<0.001) and peak expansion velocity dropped by 0.12 cm/s per 10 years (r=-0.62, P<0.001) highly significantly with age. The peak blood flow velocity decreased continuously with age (r=-0.67, P<0. 00) by 9.3 cm/s per 10 years. According to multiple regression analysis, peak blood flow velocity seems to reflect the changes of several structural and functional parameters in one; intima-media thickness was determined by diastolic arterial diameter and age as independent variables. The data indicate that a multiparametric assessment may contribute to a better understanding of vascular aging and might be the basis for further studies to evaluate the association of atherosclerotic risk factors and/or major vascular disease with local changes in the CCA.

Physical performance and cardiovascular and metabolic adaptation of elite female wheelchair basketball players in wheelchair ergometry and in competition

Spinal cord injury leads to a pronounced reduction of cardiovascular, pulmonary, and metabolic ability. Physical activity, up to and including high-performance sports, has obtained importance in the course of rehabilitation and the postclinical phase. Thirteen elite female wheelchair basketball players from the German National Basketball Team and 10 female sedentary spinal cord-injured persons were examined in the study. Heart volume was measured by an echocardiography. All subjects underwent a graded exercise test on a wheelchair ergometer. Additionally, heart rate, lactate, and player points were measured during a competitive basketball game in wheelchair basketball players. Cardiac dimensions were larger for spinal cord-injured wheelchair basketball players (620.3 ml; 9.6 ml x kg(-1)) in comparison with spinal cord-injured persons (477.4 ml; 8.2 ml x kg(-1)) but did not exceed the heart volume of untrained nonhandicapped persons. In contrast, athletes with amputations or those having had poliomyelitis reached training-induced cardiac hypertrophy in relation to body mass (713.7 ml; 13.2 ml x kg(-1)), as observed in nonhandicapped athletes. During graded wheelchair ergometry, wheelchair basketball players showed a higher maximal work rate (59.9 v 45.5 W), maximal oxygen consumption (33.7 v 18.3 ml x min(-1) x kg(-1)), and maximal lactate (9.1 v 5.47 mmol x l(-1)) without a difference in maximal heart rate and workload at AT4 than did spinal cord-injured persons. The average heart rate during the wheelchair basketball game was 151 x min(-1), and the lactate concentration was 1.92 mmol x l(-1). Female athletes with a less severe handicap and higher maximal oxygen consumption during the graded exercise test reached a higher game level in the evaluation. During the competitive basketball game, high cardiovascular stress was observed, indicating a fast aerobic metabolism; the anaerobic lactic acid capacity played a subordinate role. Wheelchair basketball is an effective and suitable sport to enhance physical performance and to induce positive physiological adaptations.

[Importance of increased physical activity in ambulatory cardiovascular prevention]

Current trends in public health provided potential arguments to, first, intensify the recommendations of a physically active lifestyle in the primary prevention of atherosclerosis and, second, to prescribe a supervised outpatient exercise training program for secondary prevention of cardiovascular diseases. Regular physical exercise may positively influence cardiovascular risk factors (overweight, hypertension, hyperlipoproteinaemia, insulin resistance, hemostatic markers). Physical conditioning modifies the body composition in favor of an increased skeletal muscle mass, changes the eating habits, and other life style characteristics. The dietary modifications characterized by a low-fat, more vegetarian food supports the weight control and the adjustment of the other metabolic risk factors. All these changes are suitable to reduce the manifestation of atherosclerosis and to minimize the risk of an acute thromboembolic arterial occlusion. Physical conditioning on one's own initiative in primary prevention or an exercise training program supervised by health professionals in secondary prevention of atherosclerosis should predominantly include a low intensive aerobic endurance exercise training. Lactate concentration in capillary blood can be measured to objectify and regulate exercise intensity. The additional energy turnover should amount to a minimum of 1,000 kcal and a maximum of 3,500 kcal weekly. This energy expenditure could be realized either with an increased physical activity level in daily routine (e.g., stair climbing, go for a walk, gardening) or by a regular leisure-time physical exercise. A turnover of 300 kcal per session should be prescribed. In long-term clinical trials investigating the benefit of primary and secondary cardiovascular prevention a reduction of the cardiovascular mortality of about 20-30% has been demonstrated.

Catecholamines, heart rate, and oxygen uptake during exercise in persons with spinal cord injury

The purpose of this study was to investigate the influence of different injury levels in persons with spinal cord injury (SCI) on epinephrine (Epi) and norepinephrine (NE) at rest and during graded wheelchair exercise and the related changes in heart rate and O2 uptake (VO2). Twenty tetraplegics (Tetra), 10 high-lesion paraplegics (HLPara), 20 paraplegics with SCI below T5 (MLPara), and 18 able-bodied, nonhandicapped persons (AB) were examined. Because of the higher level of interruption of the sympathetic pathways, Tetra persons showed lower Epi and NE at rest and only slight increases during exercise compared with all other groups; the Tetra subjects' impaired cardiac sympathetic innervation caused restricted cardioacceleration and strongly reduced maximal VO2. When compared with AB persons, HLPara had comparable NE but lower Epi levels as a result of partial innervation of the noradrenergic system and denervation of the adrenal medulla. MLPara subjects showed an augmented basal and exercise-induced upper spinal thoracic sympathetic activity compared with AB subjects. The increase in heart rate in relation to VO2 was higher in HLPara because of a smaller stroke volume as a result of venous blood pooling. The different exercise response in persons with SCI is a result of the interruption of pathways in the spinal cord to the peripheral sympathetic nervous system in addition to the motor paralysis.

Heart rate deflection compared to 4 mmol x l(-1) lactate threshold during incremental exercise and to lactate during steady-state exercise on an arm-cranking ergometer in paraplegic athletes

The deflection point (DP) of the heart rate in relation to the work rate (WR) of 8 male endurance-trained paraplegics and 11 male physically active sports students was investigated during nonsteady-state incremental arm cranking ergometry (IT) and compared to the 4 mmol x l(-1) blood lactate concentration threshold and to blood lactate concentration in steady-state exercise (SST). Heart rate, and lactate concentration from capillary blood, were determined at rest, during IT and SST. The DP was calculated by linear regression analysis of the heart rate during IT. The SST consisted of three consecutive exercise intensities over a period of 8 min at exercise intensities of 10 W below, and at 10 W above the work rate at deflection point (WRDP). No difference was found between the paraplegics and non-handicapped subjects regarding heart rate and blood lactate concentration at rest and during exercise. A DP was established in all the paraplegics and in 72.7% of the non-handicapped subjects, but lactate accumulation was observed in 75% of the paraplegics and in 62.5% of the non-handicapped subjects at the lowest intensity of SST. In summary, endurance-trained paraplegics with an injury level below T5 showed heart rate and blood lactate concentration values comparable to non-handicapped subjects during IT. A linear increase at moderate exercise intensities and a levelling-off at higher to maximal intensities could be identified in all the paraplegics and in 72.7% of non-handicapped subjects. The determination of the anaerobic threshold by DP should be applied with caution, since no causal relationship of DP and the anaerobic threshold was found and the WRDP tended to overestimate threshold values.

Importance of TNF-alpha and leptin in obesity and insulin resistance: a hypothesis on the impact of physical exercise

Obesity is associated with an increased incidence of insulin resistance, dyslipoproteinemia, and hypercoagulability. In a more recently established hypothesis of body weight control and regulation of metabolism, the adipocyte secretes leptin and locally expresses TNF-alpha, the latter being responsible for the expression of metabolic cardiovascular risk factors. TNF-a mRNA expression and TNF-alpha protein are greatly increased in adipose tissue from obese animals and humans. Elevated TNF-alpha expression induces insulin resistance by downregulating the tyrosine kinase activity of the insulin receptor and decreasing the expression of GLUT-4 glucose transporters. TNF-alpha also reduces lipoprotein lipase activity in white adipocytes, stimulates hepatic lipolysis, and increases plasminogen activator inhibitor-1 content in adipocytes. Moreover, adipocytes secrete leptin, a molecule with a secondary cytokine structure whose concentrations correlate with the amount of fat tissue. Increased leptin levels downregulate appetite and increase sympathetic activity and thermogenesis in the hypothalamus. Diet-induced weight loss reduces adipose TNF-alpha expression and serum leptin levels and is associated with improved insulin sensitivity and lipid metabolism. Although exercise has also been shown to reduce leptin levels, an influence on TNF-a expression in adipocytes or muscle cells has not yet been demonstrated.

Zinc, iron, and magnesium status in athletes--influence on the regulation of exercise-induced stress and immune function

Intense physical exercise has been shown to be associated with immunosuppression and increased rate of infection. The immunosuppressive effect of exhaustive exercise has been attributed to a reduced helper/suppressor T-cell ratio, low salivary levels of immunoglobulin-A, decreased lymphocyte proliferative response and natural killer cell activity, and elevation of stress hormones. Yet some athletes can withstand intense training periods without health problems while others are prone to infections. Thus it has been postulated that other factors may interfere with immunoregulation. The notion that macro- and micronutrients are involved in the regulation of immunological processes and the ability to cope with muscular and systemic exercise stress has been gaining attention. Particularly trace elements have been shown to be related to cell mediated and humoral immunity such as NK-cell activity, T- and B-cell functions, and cytokine release. Many investigations have reported decreased concentrations of trace elements in blood and tissues after training and competition. However, the magnitude of losses is highly dependent on the type and intensity of exercise, the individual regulatory state, and most important, nutrition. This paper reviews the data on zinc, iron, and magnesium status in athletes and summarizes the consequences of deficiencies in these trace elements regarding exercise tolerance and immune function. These elements were chosen since there is evidence they are related to exercise-induced stress and immune function.

Assessment of carotid wall motion and stiffness with tissue Doppler imaging

In this study, the wall motion of the common carotid artery was characterized by measuring wall-motion velocity (Wv) with tissue Doppler imaging (TDI) in 78 male and female subjects (16-75 y) with no history of cardiovascular disease. The near and far arterial wall showed essentially different Wv patterns. To assess the vascular systolic distension, the Wv of the near and far arterial walls were measured and a Wv index was calculated by subtracting the far Wv from the near Wv. Aging was associated with a 2.0-2.5-fold decrease of peak Wv index. Corrected for carotid diameter and blood pressure, the peak Wv index and mean systolic acceleration to the peak Wv correlated highly with arterial distensibility (r = 0.81 resp. r = 0.75) and compliance (r = 0.73 resp. r = 0.68). This study demonstrates the feasibility of TDI in the characterization of wall motion patterns and in the assessment of common carotid artery stiffness.

[LDL subfractions and coronary heart disease--an overview]

Low density lipoproteins are heterogeneous in particle size, density, and physical as well as chemical properties. Regarding size and density, LDL can be divided into two main profiles, LDL pattern A with elevated concentration of large, buoyant LDL particles and LDL pattern B with increased concentration of small, dense LDL particles. The latter is particularly expressed in insulin resistance and is associated with elevated serum triglycerides and reduced concentrations of HDL and particularly HDL2 cholesterol. The LDL profile of increased concentration of small, dense LDL particles has shown to be associated with an increased risk of cardiovascular events. The LDL profile is partly genetically determined, but can be improved by non-pharmacological (exercise, diet) and pharmacological intervention. It remains to be confirmed whether the LDL subfraction profile is an independent lipid risk factor besides HDL2 cholesterol and triglycerides, but it is certainly a valuable indicator assessing metabolic cardiovascular risk.

Three mitochondrial DNA restriction polymorphisms in elite endurance athletes and sedentary controls

This study examined the associations between elite endurance athlete (EEA) status and three mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) in the subunit 5 of the NADH dehydrogenase (MTND5) locus and one in the D-loop region. A group of 125 Caucasian male EEA well endowed with the phenotypic expression of VO2max (78.9 +/- 3.8 mL x kg(-1) x min(-1), mean +/- SD) and 65 sedentary controls (SCON: VO2max = 39.8 +/- 8.2 mL x kg(-1) x min(-1)) participated in the study. VO2max was determined during an incremental exercise test on a cycle ergometer or a motor-driven treadmill. mtDNA was extracted from white blood cells or lymphoblastoid cell lines and specific regions were amplified by the polymerase chain reaction. The Pearson Chi-square statistic test and Fisher exact test revealed no significant association (P > 0.05) between any of the three mtDNA RFLPs and EEA status. The MTND5-BamHI RFLP at bp 13,470 (morph 3) was found in 12.8% of the EEA and 12.3% of the SCON (chi2 = 0.009, P = 0.92). The prevalence of the MTND5-Ncil RFLP at bp 13,364 (morph 2) was 12.9% and 14% for the EEA and SCON, respectively (chi2 = 0.043, P = 0.83). The D-loop-KpnI RFLP at bp 16,133 (morph 1) was found in 5.8% of the EEA and in 1.6% of the SCON (Fisher exact test = 1.80, P = 0.18). The MTND5-HincII RFLP at bp 12,406 (morph 1) was not present in this study sample. These results indicate no evidence for a difference in the frequency of two polymorphic restriction sites in the subunit 5 of the NADH dehydrogenase gene of mtDNA and one in the D-loop region between elite endurance athletes and sedentary controls.

Aerobic exercise as therapy for cancer fatigue

PURPOSE

Fatigue and impairment of physical performance are common and severe problems of cancer patients. We describe the effect of an aerobic exercise program designed for cancer patients suffering from these symptoms.

METHODS

Five cancer patients (4 female, 1 male, age 18 to 55), participated in the training program. Fatigue had been present for a time ranging between 5 wk and 18 months and hindered the patients from carrying out normal daily activities. The training program consisted of walking daily on a treadmill with an intensity corresponding to a lactate concentration of 3 +/- 0.5 mmol.L-1 and was carried out for 6 wk.

RESULTS

By the end of the exercise program we observed an improvement in maximal physical performance (from 6.4 +/- 0.4 km.h-1 to 7.5 +/- 0.9 km.h-1, P < 0.05) and maximal walked distance (from 1640 +/- 724 m to 3300 +/- 953 m, P < 0.05). Heart rate and lactate concentration by an equivalent submaximal workload (5 km.h-1) were significant reduced (from 138 +/- 21 beats.min-1 to 113 +/- 20 beats.min-1, P < 0.05, and from 2.6 +/- 1.4 mmol.L-1 to 1.3 +/- 0.6 mmol.L-1, P < 0.05); all patients experienced a clear reduction of fatigue and could carry out normal daily activities again without substantial limitations.

CONCLUSION

We conclude that an aerobic exercise program of precisely defined intensity, duration, and frequency can be prescribed as therapy for primary fatigue in cancer patients.

[Sports in the heart rehabilitation group--experiences with ambulatory rehabilitation at home]

Regular physical exercise has shown to be beneficial for patients with cardiovascular disease. Therefore cardiac rehabilitation in Germany is continued for years after hospital discharge in outpatient cardiac exercise groups which meet twice a week under the guidance of a physician and a sports instructor. Before participation cardiac patients have to be examined including exercise tests and echocardiography for assessment of contraindications for exercise therapy as well as individual exercise capacity. Patients are assigned to two groups with different levels of exercise intensity according to their symptom-free work-capacity (cutoff level 1 W/kg). During exercise sessions sports-specific forms of exercise such as stretching, aerobic exercise or ball games are accompanied by psychosocial elements such as stress management. This global approach is intended to improve cardiovascular risk factors, cardiac function, and work capacity as well as to stabilize the patient psychologically in order to accelerate social integration. Recently these groups have opened towards patients after cardiac transplantation or with severe heart failure. Therefore, cardiac exercise groups play a central role in cardiac rehabilitation long after the acute cardiac event.