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Biomedical subjects

H Löllgen

Publications and source records attributed to H Löllgen.

At least 73 records · Page 4Linked to original sources
PubMed1980

Muscle metabolites, force, and perceived exertion bicycling at varying pedal rates.

Muscle metabolites, force, and perceived exertion bicycling at varying pedal rates. Med. Sci. Sports Exercise, Vol 12, No. 5, pp. 345-351, 1980. The relative significance of central (VE, Vo2, heart rate) or peripheral (muscle tension, muscle metabolites) factors on perceived exertion (RPE) was investigated with bicycle exercise by varying pedal rate while maintaining a constant power output. Six healthy male subjects exercised at zero load, submaximal (70% Vo2max) and maximal exercise intensities with pedal rates of 40, 60, 80, and 100 rpm. With changing pedal rate and constant power output, there were numerous examples of significant changes in the central factors with no change in RPE and vice versa. Similarly, measures of muscle and blood lactate, NAD, glycogen, ATP, and CP failed to demonstrate any local metabolic factor that correlated with RPE. Force exerted on the pedals and the rate of force generation approximated RPE changes, but the detailed correlation analysis was nonsignificant. None of the central or peripheral factors alone are related to RPE. Thus, RPE must be derived from a number of peripheral and/or central factors in a complex manner.

Adult↗
PubMed1979

Estimation of cardio-pulmonary function by means of the age equivalent.

Many of the cardio-pulmonary function variables depend on age showing a deterioration with increasing age. Reversing this relationship age can be estimated by cardio-pulmonary variables. In the present study, age was estimated using a multiple regression equation including variables measured at rest and at exercise. The difference between estimated and chronological age is called the age equivalent. (delta A). Formulas for estimating delta A have been established in 59 strictly defined normal subjects and applied on groups of athletes, smokers and foundry workers. Using the delta A, factors such as physical fitness, smoking habits, heaviness of work and dust exposure can be discriminated. It is concluded that the age equivalent is more useful in epidemiological surveys than in individual analysis of functional capacity. The age equivalent may be an approach to data reduction in cardio-pulmonary function analysis.

Adult↗
PubMed1978

NAD in muscle of man at rest and during exercise.

NAD can be used to assess the adequacy of oxygen availability to the respiratory chain. An enzymatic assay was established for NAD in human muscle biopsy samples. It gave reliable, reproducible results. The variation within and between subjects was less than 12%. Muscle NAD and lactate were determined at rest, and after bicycle ergometry work requiring approximately 75 and approximately 100% VO2 max (six subjects, four tests each). A positive (P less than 0.01) linear relationship between resting muscle NAD and percent slow twitch fibers was found, suggesting that fiber types may have different NAD content. Muscle NAD decreased during submaximal and maximal work (P less than 0.05). A large portion (73%) of the NAD reduction could be accounted for by increased muscle water. No relationship could be established between NAD and lactate. The negative linear relationship (P less than 0.01) between the muscle/blood ratio and percent slow twitch fibers is another indication of the fiber having different metabolic responses to the activity.

Adult↗
PubMed1978

Use of isoproterenol infusion to study intrapulmonary gas mixing in man.

In the present investigation, the effect of an increased cardiac output on intrapulmonary gas mixing was studied in healthy male subjects. Increase of heart rate and cardiac minute output was induced by infusion of isoproterenol, intrapulmonary gas mixing was analyzed by simultaneous washout of inert gases widely differing in molecular weight (helium and sulfur hexafluoride). Parameters, appropriate to indicate quality of gas mixing, have been crossover point (COP) and separation index (SI). During isoproterenol-induced tachycardia, the COP occurred earlier and the SI decreased. Both changes then demonstrate an improved gas intrapulmonary mixing. The movement of the heart reduces stratified inhomogeneity.

Adult↗
PubMed1978

[Fully automatic computer-analysis of electrocardiograms in clinical routine (author's transl)].

A fully automated Ecg recording and interpretation system (Hewlett Packard HP 5) consisting of a central computer and two peripheral units was evaluated during a four-month period. Ecgs were transmitted via public telephone lines, as was the report from central station to peripheral recording and print-out unit. Within a few seconds after recording and print-out unit. Within a few seconds after recording and transmission a preliminary report is available in printed format. The transmitted Ecgs are stored at the central computer and are being retrieved and evaluated manually there. Three cardiologists read the tracings and furnished final reports. 468 Ecgs were thus compared in our test time of 10 days for statistical evaluation with the following results: 1. 73.1% of all statements were read correctly by the computer. 2. There is a large range of diagnostic accuracy between 0% and 100%. 3. The evaluation of Ecg changed by cardiologists reflects the individual experience of the controllers regarding the Ecg statements as well as computer-dependent possibilities like modification etc. of Ecg. 4. As an example the diagnosis "myocardial infarction" is compared with other Ecg computer programs by means of a quality index calculated from sensitivity and specificity: HP 5 with 158.5 points reaches a similar level as the Pipberger program with 162.6 and the Bonner with 159.5 points. 5. Referring to false negative results this program is acceptable in all diagnostic groups with ca. 8%, except conduction defects with 17.7%. 6. Referring to false positive results the diagnostic groups myocardial infarction/ischemia and conduction defects are not satisfactory with 36.5% and 23.4%. 7. In all the tested system seems to be very useful in routine Ecg interpretation of bigger hospitals.

Cardiology↗
PubMed1977

Heart rate and perceptual response to exercise with different pedalling speed in normal subjects and patients.

The perceived exertion rating (RPE) scale of Borg was used to investigate the relationship between perceived exertion and pedalling rate. Normal subjects and patients with chronic obstructive lung disease (Cold) were studied in repeated test series. Work load, applied in a random order, varied from 2.5 to 10 mkp/s (patients) and 5 to 20 mkp/s (normals). Pedalling rate varied from 2.5 to 10 mkp/s (patients) and 5 to 20 mkp/s (normals). Pedalling rate varied from 40 to 60, 80, 100 rpm. At constant work load, RPE decreases during increasing pedalling rate. With respect to validity, RPE, showing a closer relationship to work load than to heart rate, seems to reflect perception of physical stress rather than perception of physiological strain. In addition, the results raise the question of standardization of pedalling rate in bicycle ergometry.

Adult↗