Muscular Oxygen Uptake Kinetics in Aged Adults.

Pulmonary oxygen uptake (V˙O2) kinetics and heart rate kinetics are influenced by age and fitness. Muscular V˙O2 kinetics can be estimated from heart rate and pulmonary V˙O2. In this study the applicability of a test using pseudo-random binary sequences in combination with a model to estimate muscular V˙O2 kinetics was tested. Muscular V˙O2 kinetics were expected to be faster than pulmonary V˙O2 kinetics, slowed in aged subjects and correlated with maximum V˙O2 and heart rate kinetics. 27 elderly subjects (73±3 years; 81.1±8.2 kg; 175±4.7 cm) participated. Cardiorespiratory kinetics were assessed using the maximum of cross-correlation functions, higher maxima implying faster kinetics. Muscular V˙O2 kinetics were faster than pulmonary V˙O2 kinetics (0.31±0.1 vs. 0.29±0.1 s; p=0.004). Heart rate kinetics were not correlated with muscular or pulmonary V˙O2 kinetics or maximum V˙O2. Muscular V˙O2 kinetics correlated with maximum V˙O2 (r=0.35; p=0.033). This suggests, that muscular V˙O2 kinetics are faster than estimates from pulmonary V˙O2 and related to maximum V˙O2 in aged subjects. In the future this experimental approach may help to characterize alterations in muscular V˙O2 under various conditions independent of motivation and maximal effort.

Effects of Wearing Compression Stockings on the Physical Performance of T2DM Men with MetS.

Metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) are associated with macro- and microcirculatory complications that reduce physical performance. Wearing compression garments to potentially optimize hemodynamics has been discussed. This study investigates the effects of wearing compression stockings on physical performance-related variables in type 2 diabetic men with metabolic syndrome (n=9, 57±12 years, BMI: 36±4 kg/m(2)). Participants served as their own controls in a randomized 3*3 crossover study wearing below-knee stockings with either compression (24 or 30 mmHg ankle pressure) or no compression. Venous pooling and lower limb oxygenation profiles were determined with near-infrared spectroscopy and arterial oxygen saturation was determined using a pulse oxymeter. Measurements were performed in the supine lying position, during standing, following 10 tiptoe exercises and after submaximal intensity cycling. In addition, lactate and erythrocyte deformability were analyzed in capillary blood pre- and post-exercise. Erythrocyte deformability was analyzed using a laser-assisted optical rotational red cell analyzer. No significant differences in any variables when wearing different compression or regular stockings were evident at any point of measurement. This study did not reveal any beneficial effects of wearing compression stockings at rest and during acute bouts of moderately intense exercise in this particular patient group.

Long-term endurance exercise decreases antiangiogenic endostatin signalling in overweight men aged 50-60 years.

BACKGROUND: Endurance training may decrease the risk of coronary artery disease. It has been speculated that these effects may be due to an exercise-induced stimulation of angiogenesis. The underlying mechanisms are not yet clear. Therefore, using ELISA, we investigated the plasma level of vascular endothelial growth factor (VEGF, angiogenic factor) and endostatin (antiangiogenic factor) in a group of untrained men aged 50-60 years with obesity. METHODS: All men were randomised into a "running" group (training 3 times/week, 60 min each, n = 7), a "cycling" group ( training 3 times/week, 90 min each, n = 7) and a sedentary control group ( n = 7). Both training groups worked at moderate intensity (2-4 mmol/l lactate). The intervention had a duration of 6 months. Before and after this period, blood samples were taken from the participants at rest and they underwent a medical investigation. RESULTS: Body mass index (BMI), systolic and diastolic blood pressure, and plasma levels of VEGF and endostatin were comparable in all three groups. Endurance training significantly reduced BMI in both exercise groups (mean (SEM) before v after 29.7 (0.7) v 29.1 (0.6) kg/m2 and 31.1 (0.7) v 30.1 (0.9) kg/m2 for the running and cycling groups respectively) but not in the control group (30.0 (1.0) v 30.2 (0.8) kg/m2). Endurance training did not influence VEGF plasma level (before v after 1.3 (0.4) v 1.5 (0.2) ng/ml for the running group; 1.6 (0.3) v 1.5 (0.2) ng/ml for the cycling group; and 2.5 (0.6) v 2.1 (0.7) ng/ml for the control group). Plasma level of endostatin was significantly reduced in both exercise groups (mean (SEM) before v after: 20.9 (1.6 v 17.5 (1.0) ng/ml and 21.3 (1.4 v 18.0 (1.6) ng/ml for the running and cycling groups respectively) but not in controls (19.7 (1.3 v 17.7 (1.1 ng/ml). CONCLUSIONS: Endurance training may reduce the antiangiogenic mechanisms in men aged 50-60 years by reducing endostatin plasma level and this may subsequently decrease the risk of cardiovascular disease.

Endurance training alters enzymatic and rheological properties of red blood cells (RBC) in type 2 diabetic men during in vivo RBC aging.

This study examines the effects of endurance training on red blood cells (RBC) in seventeen non-insulin-dependent type 2 diabetic men with a special focus on in vivo RBC aging. Venous blood was collected pre- and post-training at rest. RBC from whole blood and RBC separated according to cell age by density-gradient centrifugation were analyzed. RBC deformability was measured by ektacytometry. Immunohistochemical staining was performed to quantify the RBC-nitric oxide (NO) synthase activation (RBC-NOSSer1177) because RBC-NOS-produced NO can contribute to increased RBC deformability. The proportion of "young" RBC was significantly higher post-training. RBC deformability of all RBC (RBC of all ages) remained unaltered post-training. During RBC aging, RBC deformability decreased in both pre- and post-training. However, the training significantly increased RBC deformability in "young" and reduced their deformability in aging RBC. RBC-NOS activation remained unaltered in all RBC post-training. It tendentially increased in aging RBC pre-training, but did not change during aging post-training. The training significantly reduced RBC-NOS activation in "old" RBC. Endurance training may improve the RBC system (higher amount of "young" RBC which are more deformable). It remains speculative whether changes in older RBC (reduced RBC-NOS activation and deformability) could lead to more rapid elimination of aged RBC.

Moderate physical exercise: a simplified approach for ventricular rate control in older patients with atrial fibrillation.

AIMS: This prospective pilot-study was performed to assess whether regular moderate physical activity elevates the parasympathetic tone to the atrio-ventricular node and decreases VR during permanent AF. BACKGROUND: Adequate ventricular rate (VR) control in patients with permanent atrial fibrillation (AF) is not easy to accomplish. METHODS: 10 patients (mean age 59 +/- 10 years) with permanent AF (duration: 10 +/- 8 years) underwent moderate physical exercise adjusted to their individual physical capability (45 min walking/jogging twice a week). To analyze VR control physical exercise tests and Holter-ECG recordings were performed before and after 4 months. In addition, stepwise lactate tests and psycho-pathometric examinations were obtained. RESULTS: After 4 months of training, there was a trend toward a decrease of mean VR in 24 h Holter-ECGs by 12% from 76 +/- 20 to 67 +/- 12 bpm (P = 0.05) while there was no significant decrease of the minimal VR (38 +/- 8 vs. 36.3 +/- 4.5 bpm, P = 0.54). At a lactate threshold of 2 mmol/l there was a trend towards an increase of the running speed from 105 +/- 11 to 116 +/- 12 m/min (P = 0.05). A significant VR decrease of 8% (range 5-10%) was observed at almost all exercise levels during exercise treadmill testing. Increases of exercise capacity and decreases of VR were accompanied by subjective improvements of health perception. CONCLUSION: Regular moderate physical activity decreases VR at rest and during exercise while increasing exercise capacity. Physical training should be taken into account for ventricular rate control during AF.

[The PreFord Study. A prospective cohort study to evaluate the risk of a cardiovascular event (overall-collective) as well as a prospective, randomized, controlled, multicentre clinical intervention study (high-risk-collective) on primary prevention of cardiovascular diseases in the Ford Motor Company employees in Germany]. / Die PräFord-Studie. Prospektive Kohortenstudie zur Bewertung des Risikos für ein kardiovaskuläres Akutereignis (Gesamtkollektiv) sowie eine prospektive, randomisierte, kontrollierte, multizentrische klinische Interventionsstudie (Hochrisikoteilkollektiv) in der Primärprävention von Herz-Kreislauferkrankungen bei Mitarbeitern der Firma Ford in Deutschland.

The PreFord Study is a multicenter prospective cohort study to evaluate guideline based risk management on primary prevention of cardiovascular diseases. Furthermore a randomised controlled trial (RCT) will be designed to analyse the effect of a special intervention program. 40,000 employees of the Ford Motor Company, Visteon Company and Deutz Company in Germany will be included, monitored for ten years and the following primary endpoints will be investigated: 1. evaluation and comparison of established and newly developed risk-scores, 2. the relative impact of single and combined cardiovascular risk factors on cardiovascular diseases, 3. the influence of a novel occupationally integrated ambulant rehabilitation program in combination with a guideline oriented optimal drug therapy within a high risk group on the primary endpoint: risk reduction by, 4. the influence of this intervention on secondary endpoints: death, myocardial infarction and stroke, combined appearance of angina pectoris and hospitalisation, occurrence of cerebral circulatory disorder and hospitalisation, occurrence of peripheral occlusive arterial disease and hospitalisation and single cardiovascular risk factors and cost-benefit-analysis. Beginning with an cross sectional study there will be a systemic screening of cardiovascular risk profiles, of anthropometric data and different lifestyle-factors. Based on these data participants will be differentiated into three risk-groups according to the risk score of the European Society of Cardiology (risk of a lethal primary acute cardiovascular event: I < or = 1%; II > 1-< 5% and III > or = 5%). In the following longitudinal study different strategies will be applied: Group I: low risk (< 0.5% per year): repetition of the investigation after five and ten years. Group II: middle risk, (0.6% to 1.4% per year), repetition of the investigation every two years, instruction of the patients general practitioner (GP) with respect to a risk factor oriented and evidence based treatment. Group III: high risk, (> 1.5% per year or >15% within the next 10 years) will be randomised into two interventional groups. The first one, the intervention-group "PreFord" will perform an occupational integrated rehabilitation program (2,5-3 hours twice a week, for 15 weeks according to the BAR guidelines) with a following engagement in heart-groups and an annual repetition of the check-ups. The second group, the "classic" intervention-group will be treated evidence based in cooperation with their GP. As a result of this long term interventional study efficient, area wide implementable and economically feasible prevention concepts with special regards to operational healthcare will be developed and evaluated. Core elements will be exercise- and lifestyle-oriented concepts as well as guideline-based pharmacotherapy.