Constitutional features of the reaction of the hemostatic system to a physical load

This study involves 72 young men with various levels of working efficiency and elucidates the relationship between human morphological constitution by the type of age-related evolution of the organism and parameters affecting hemostasis. As suggested by V.G. Shtefko, the measured value of the trochanteric index (TI) is compared to the reaction of the hemostatic system to graded moderate veloergometric load. It was found that decreased coagulability and activation of fibrinolysis take place in untrained men with high TI values in response to a load, while stimulation of blood coagulation and inhibition of its fibrinolytic activity occurs in men with low TI values. There is a significant correlation between the TI value and reaction of the hemocoagulation system to a load. Under the impact of a load, hemocoagulation and fibrinolysis are stimulated in persons with a relatively high working efficiency and high TI values, and coagulation is inhibited and fibrinolysis is more often stimulated in those with low TI values. Our conclusion is that a more favorable and stable response of the hemostatic system to a physical load takes place in subjects with the normo- and hyperevolutive constitutional types in conditions of both low and relatively high working efficiency levels. Low TI values, combined with low working efficiency level, are a risk factor for the development of thromboembolism complications in men, and these may be provoked by physical activity.     

Peculiarities of hemostasis reactivity under stress load in persons with different degree of physical training

Healthy young persons with different degrees of physical training have been impacted with exposure to a stress (a single physical exercise). It caused unidirectional hypercoagulative shifts and activation of anticoagulant and fibrinolytic blood systems. It was shown that changes of the untrained individuals' haemostatic parameters could be adjusted with adaptogen preliminary administration. The adaptogen administration in trained individuals resulted in disadaptive shifts in the haemostatic system. These contradictory changes indicate different levels of subject's adaptive potential.     

Ultrastructural characteristics of rat neuromuscular junctions after physical load

It is interesting to ascertain the adaptive reaction of rat neuromuscular junctions (NMJ) of muscle fibers of different types to a chronic physical load. We examined ultrastructural changes in NMJ following both static load (pre- and postnatal ontogenesis of Wistar rats till a 2 month age took place under a constant rotation on the centrifuge at hypergravity conditions 2G), and after three kinds of dynamic loads (1/run on treadmill with a speed 35 m/min for 6 wks, 10-60 min/day; 2/swimmings, each 10 hrs/day for 10 days; 3/strength exercises on a vertical treadmill with load for 6 wks). Differences in NMJ reaction of muscle fibers of the same type to various loads were established. A low secretory activity of axonal terminals of type I muscle fibers of m. soleus was shown after the static load. The dynamic load (run) is accompanied with a high secretory activity of axonal terminals in m. soleus type I muscle fibers and of some axonal terminals of m. quadriceps femoris IIB type muscle fibers after strength exercises; the secretory activity of axonal terminals of m. quadriceps femoris IIA and IIB types muscle fibers is expressed in a lesser degree after swimming. The NMJ ultrastructure remodelling (terminal renewal) of type I muscle fibers of the 2 month old control rats increases after static and dynamic (run) loads. Some correlations between different kinds of physical load, muscle fiber type and the degree of NMJ ultrastructure transformation have been shown.     

Plasma-coagulation hemostasis in physically active subjects during adaptation to physical exercise

Basic hemorheological and pro-and anticoagulatory characteristics were studied in athletes practicing cyclic sports and patients with venous thrombosis and arterial atherosclerosis. The results of factor analysis of the entire sample indicated that changes in the procoagulatory components of the plasma-coagulation hemostasis in athletes tend to decrease the coagulatory potential of the blood. The athletes displayed a decrease in the activity of natural anticoagulants (protein C and antithrombin III). A significant decrease in the parameters of blood viscosity mainly caused by a better red cell deformability was correlated with the changes in the procoagulatory and anticoagulatory components of the hemostasis; these changes were well balanced and may be considered predominant. Damage to the vascular endothelium and disturbances in the red cell microrheology were found to be the most important factors in the patients with peripheral arterial disease. Acute deep vein thrombosis was associated with a strong activation of procoagulatory components and dysfunction of natural anticoagulants.     

Seasonal and individual characteristics of the response of the fibrinolytic system of blood to physical exercise

The response of the fibrinolytic system of the blood of 33 untrained subjects (16 males and 17 females 18 years old) to a single 20-min bicycle-ergometric large-capacity load (N _male = 2.66 W/kg, N _female = 2.3 W/kg) was studied for 1 year. It is known that the blood fibrinolytic activity at rest has seasonal characteristics: it is relatively high in autumn and spring and low in winter and summer. On average, physical activity in winter and summer stimulates the blood clot lysis, whereas in autumn and spring this stimulation is not observed. The direction and intensity of the response of the fibrinolytic system to exercise have individual features: in autumn and spring they depend on its initial state (increase when the blood FA is low and decrease when it is high) and fluctuate widely, whereas in winter and summer this dependence is not observed. According to the direction of response to the load and its persistence, three types of responses can be distinguished: (a) hyperfibrinolytic, which is characterized by an increase in FA during exercise throughout the year, with a constantly low initial level of fibrinolytic activity at rest; (b) hypofibrinolytic, which is characterized by a stable suppression of fibrinolysis after exercise regardless of the season and the initial level of fibrinolytic activity, with a high fibrinolytic activity at rest in autumn and spring and a low fibrinolytic activity in winter and summer; and (c) unstable, in which the direction of the response of the fibrinolytic system to exercise varies. It is concluded that the development of thromboembolic complications after exercise can be expected with the highest and lowest probability in the subjects with the hypofibrinolytic and hyperfibrinolytic response, respectively.     

Morphofunctional characteristics of enzyme activity of the muscles in ontogenesis and after physical load

By means of histochemical methods using cytospectrophotometer in femoral muscles of white rats 1-, 3- and 12-month-old enzymatic activity of anaerobic and aerobic cycles has been estimated. The greatest changes occur after 20 days of physical load in 1- and 12-month-old animals. The semitendinous muscle (ventral origin), consisting mainly of red muscle fibers, works chiefly in aerobic regime and possesses a more manifested succinate dehydrogenase activity, and the quadriceps muscle (dorsal origin) consists principally of white fibers and its lactate dehydrogenase activity changes more noticeably.     

Ethylene in relation to the response of roots to physical impedance

Plant and Soil - When the axial growth of bean roots (Vicia faba, L., variety Broad Windsor) was impeded by a barrier, the rate of ethylene evolution increased by as much as six times that of...     

Naloxone alters the early response to an inspiratory flow-resistive load

In a previous study in unanesthetized goats, we demonstrated that cerebrospinal fluid levels of beta-endorphin were significantly elevated after 2.5 h of inspiratory flow-resistive loading. Naloxone (NLX) (0.1 mg/kg) administration partially and transiently reversed the tidal volume depression seen during loading. In the current study, we tested the hypothesis that endogenous opioid elaboration results in depression of respiratory output to the diaphragm. In six studies of five unanesthetized goats, tidal volume (VT), transdiaphragmatic pressure (Pdi), diaphragmatic electromyogram (EMGdi), and arterial blood gases were monitored. A continuous NLX (0.1 mg/kg) or saline (SAL) infusion was begun 5 min before an inspiratory flow-resistive load of 120 cmH2O.l-1.s was imposed. Our data show that the depression of VT induced by the load was prevented by NLX as early as 15 min and persisted for 2 h. At 2 h, Pdi was still 294 +/- 45% of the base-line value compared with 217 +/- 35% during SAL. There was no difference in EMGdi between the groups at any time. However, the augmentation of Pdi was associated with a greater increase in end-expiratory gastric pressure in the NLX group. We conclude that the reduction in VT and Pdi associated with endogenous opioid elaboration is not mediated by a decrease in neural output to the diaphragm, but it appears to be the result of a decrease in respiratory output to the abdominal muscles.     

Kinetics of the chondrocyte biosynthetic response to compressive load and release

To gain insight regarding the rate at which cartilage tissue can sense and respond to a dynamic mechanical stimulus, we have examined the time-course of changes in biosynthetic activity following both the application and release of a static compressive stress. Cartilage harvested from the reserve zone of calf epiphyseal plate was subjected to unconfined static compressive stresses of 0, 0.25 and 0.5 MPa. Incorporation of [35S]sulfate and [3H]proline was measured during loading periods of less than 1 to 26 h and after preloading periods of 0.5, 2 or 12 h. During loading, total incorporation decreased to steady levels with time constants estimated to be 0.25-4 h (proline) and 1-5 h (sulfate). Proline incorporation exceeded control levels for 3 h after release of a 2 or 12 h preload. Sulfate incorporation remained depressed for at least 4 h after release of a 12 h preload and remained at control levels following release of 0.5 and 2 h preloads. We conclude that the modulation of proline incorporation by both loading and load release is faster than the modulation of sulfate incorporation. Furthermore, the response to unloading is not just the inverse of the response to loading; this nonlinearity suggests that the response to dynamic loading would not be determined simply by the time average component of the dynamic load.     

Sweating response to abrupt changes in work load

Changes in sweat rate on the palm and on the general body surface in response to stepwise increases and decreases in work load during exercise on a bicycle ergometer were examined in relation to body temperature and heart rate in six male subjects (three trained and three untrained), in an attempt to evaluate thermal and nonthermal factors responsible for those changes. In all the untrained subjects, a transient, marked increase in palmar sweat rate was observed upon an abrupt increase (and occasionally upon an abrupt decrease) in work, while an increase in sweat rate on the general body surface was also rapid and marked. On the other hand, in all the trained subjects, palmar sweat rate was low and hardly showed a substantial increase in response to an abrupt increase in work load, to which sweating on the general body surface responded slowly by a gradual increase. While sweat rate on the general body surface showed a significant correlation with esophageal temperature and with heart rate, palmar sweat rate was not correlated with esophageal temperature but was significantly correlated with heart rate. Moreover, repeated increases and decreases in work load often led to progressive weakening of palmar sweating due apparently to the development of habituation. The present results suggest that responses of sweating to stepwise changes in work load are not solely dependent upon the thermoregulatory mechanism but are affected considerably by increase and decrease in psychic excitement and/or those in discharges of the sympathetic nervous system accompanying changes in work load.(ABSTRACT TRUNCATED AT 250 WORDS)     

Respiratory response to sinusoidal work load in humans

Present study was undertaken to elucidate possible distortion of phase response and amplitude response of various respiratory parameter such as VO2, VCO2 and VE to sinusoidal work load by comparing model analysis with manual analysis. Also, an attempt was made to determine whether there is any relationship between the characteristics of response of these parameters and the aerobic capacity of subjects. Six healthy male subjects were performed exercise on an electrically braked bicycle ergometer for 32 min. The work load was varied sinusoidally between 30 watts and 60% VO2max being under anaerobic threshold with periods from 1 to 16 min. These parameters were determined in breath-by-breath mode with a computer system and mass spectrometer. In model analysis, amplitude and phase responses were well described by first order exponential model, and strong correlations were observed between magnitude of phase response or time constant of amplitude response and aerobic capacity. Manual analysis revealed that respiratory responses to sinusoidal work load are not completely sinusoidal but somewhat distorted forming saw-tooth waves with steeper downslopes.     

Reaction of human skeletal muscle fiber to a one-time physical load

NADH-tetrazolium reductase and succinate dehydrogenase activity, glycogen concentration and ultrastructure of muscular fiber of a human being was studied before and after single physical load to refusal. The revealed individual peculiarities of fiber reaction in different people allow to divide all tested people into two subgroups according to the change of succinate dehydrogenase activity.