[Transitional modes in the work of the external respiratory system under physical loading]. / Perekhodnye rezhimy raboty sistemy vneshnego dykhaniia pri fizicheskoi nagruzke.

When recording the respiratory volume (RV) in the course of a 5-minute muscular work, two types of transitory processes were revealed: an aperiodic and an oscillatory ones. The former characterises the matrix optimal way of adaptation to physical work. The latter occurs of loads in a moderate intensity. The RV fluctuations seem to reflect a "search" for the RV optimal level for a given lung ventilation. The reserve volume of expiration practically does not participate in the RV increase, thus maintaining a large enough functional residual capacity in physical load.

[Arterial impedance in transient modes of the performance of the circulation system]. / Arterial'nyi impedans pri perekhodnykh rezhimakh raboty apparata krovoobrashcheniia.

The authors consider transient processes for modifying arterial impedance, peripheral and elastic resistances of the arterial system, as well as some major hemodynamic parameters early in muscular performance. The analysis was made by applying experimental findings from 74 athletes. The transient processes were derived by using the mathematical modelling techniques on a computer. The termination of transient processes of arterial impedance and its determinants was shown to be asynchronous. Whether the values of arterial impedance at rest and during exercises of unlimited power are comparatively invariant is also discussed in the paper.

Determination of arterial impedance by non-invasive measurements.

Most studies dealing with the arterial system impedance as resistance to blood ejection from the left ventricle are based on catheterization examinations of the aorta and the great arteries. The present work shows the possibility of using non-invasive approaches and describes one of them consisting in non-invasive determination of arterial impedance by measuring arterial pressure, cardiac output and the cardiac cycle phase structure. The results are compared with those of other studies.

[Maximal modes of blood circulation]. / Maksimal'nye rezhimy krovoobrashcheniia.

In 44 sportsmen under maximal physical loads, the maximal O2 transport was effectively maintained by different modes of the circulation. The optimal mode is: Q = 2.9 + 5.43 VO2 + 0.61 V2O2 - 0.099 V3O2 (where Q is the minute blood volume; VO2--oxygen consumption). This mode involves proportional contributions of the central and the peripheral mechanisms of the organism O2 supply. The expressive mode involves increased O consumption and minute blood volume (on the average 37.72 +/- 3.0 l/min), and a relatively small arterial-venous difference (on the average 141.5 +/- 13.1 ml/l). The reduced mode of circulation involves relatively small values of the minute blood volume (on the average 29.76 +/- 1.64 l/min) and an obvious increase of the arterial-venous difference in oxygen (on the average 180.9 +/- 14.3 ml/l). Formation of one or another hemodynamic mode is related to an individual blood volume velocity. In particularly high values of the minute blood volume, the O2 transfer from capillaries is limited by the flow. A relative decrease of the minute blood volume increases the contacting time of the blood with muscle tissues aiding to excessive extraction of O2 and thereby increasing the arterial-venous difference.

[Studies of the phasic structure of the cardiac cycle by means of echocardiography]. / Issledovanie fazovoi struktury serdechnogo tsikla s pomoshch'iu ékhokardiografii.

A synchronous analysis of the variations in the diameter of the left ventricle, the mural movements of the left atrium and the mitral and aortal cusps allows the division of the cardiac cycle into 13 phases and intervals. The duration of phases calculated with the help of echocardiography is in agreement with the data provided by other methods.

[Efficacy of the Frank-Starling mechanism during physical stress]. / Effektivnost' mekhanizma Franka-Starlinga pri fizicheskoi nagruzke.

The Frank-Starling mechanism was investigated in 88 athletes exposed to physical stress and was shown to operate under physical stress in athletes with ventricular cavities of normal or moderately increased size. In athletes with physiological ventricular dilatation as a result of endurance training (over 160 ml in ultimate diastolic volume), the Frank-Starling mechanism is not normally triggered under stress: increased cardiac output is provided by greater basal blood volume reserve. With ultimate diastolic volumes of 115-159 ml, the Frank-Starling mechanism provides an optimum increase in peak stroke volume. The effectiveness of the heterometric mechanism activated by physical stress in subjects with small ultimate diastolic volumes is not sufficient as additive reserve volume cannot be increased essentially.

[The theoretical analysis of Fick's equation. On the centennial of the use of Fick's principle in physiology]. / Die theoretische Analyse der Fickschen Gleichung Zur Jahrhundertfeier der Anwendung des Fickschen Prinzips in der Physiologie

In the first section Adolf Fick's outstanding scientific performances are pointed out in their historical sequence, particularly the derivation of the laws of diffusion (1855) and the basic equation for determining the heart-minute-volume (Fm) by O2-absorption per time (V02) and arteriovenous O2-difference (AVD), known as Fick's Principle. The latter was derived theoretically in 1870 by Fick, but it found it practical employment by other investigators, in dog not before 1886 and in man not earlier than 1930. In the following two sections the universality of Fick's Principle is shown by explaining its internal relation 1. to Fick's first law of diffusion and 2. to the general law of solution. This is done by mathematical transformation of the relations (formulas)of the physical resp. the physiological standards (parameters). By analyzing the diffusion of a substance into a streaming fluid according to the first diffusion law, perfectly isomorphic equations to Fick's Principle (No. 7 and No. 9) are obtained by what Fick's formula as a determinant of the heart-minute-volume is just proved to be derivable from Fick's first diffusion law. Furthermore by transforming the trivial formula for the determination of substance concentration in a fluid provement is given, that Fick's Principle may be considered a variant of the solution theory. By this the internal relation of the so-called dilution respectively indicating methods depending on the Stewart-Hamilton-Principle to the original Fick's Principle is made visible. In the last section an attempt is made to produce a relation to 1. the so-called physical methods determining the minute volume which primarily are known as a measurement for stroke volume and frequency, and, besides that, 2. to Vierordt's equation, by which the heart-minute-volume is determinable from circulating blood volume and circulation time. This trial is made by equating the value of the minute volume given by Fick's Principle (VO2/AVD) with the product from stroke volume and beating frequency, and on the other hand by equating it with the quotient from circulating blood volume Qc and complete circulation time Tc (Qc/Tc). Finally, physiological arguments are derived from these relations, allowing an evaluation of the relative proportions in circulation adaption during muscular work of the magnitudes of changes in stroke volume, beating frequencies, or the O2-pulse.