Cognitive tests to rate physical loads versus cerebral blood flow

Cognitive tests to rate physical loads versus cerebral blood flow

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PhD A.V. Kabachkova1
Postgraduate G.S. Lalaeva1
Postgraduate A.N. Zakharova1
Dr.Med., Professor L.V. Kapilevich1, 2
1National Research Tomsk State University, Tomsk
2National Research Tomsk Polytechnic University, Tomsk

Keywords: dynamic load, static load, physical load, cerebral blood flow, cognitive activity

Introduction. Physical load leads to changes in systemic and regional blood flow with the involvement of humoral, paracrine and neural factors [3, 9]. Adaptation to physical loads is accompanied by functional [4, 7] and structural adjustments of vasculature [2, 6], including the vessels of the brain [1]. Cerebral haemodynamics, in its turn, affects cognitive functions [8]. Supporting the idea of the effect of regular exercise on cognitive performance, К. Erickson and А. Kramer [5] showed a direct correlation between an increased level of physical activity, improvement of cognitive processes and the size of the hippocampus. 

Objective of the study was to profile the cerebral blood flow variations in counting tests after the rated static and dynamic physical loads.

Methods and structure of the research. Subject to the study were athletes of cyclic and acyclic sport disciplines (n=40, qualified at least Candidates for Master of Sport) split up into 2 equal groups, namely Track and Field Group (TFG) and Weightlifting Group (WLG). Two Reference Groups (RG1 and RG2) were composed of 40 university students qualified with the basic health group. All the subjects were 18-23 years old. Rheoencephalographs (REG) of the subjects were recorded at relative rest, and then the subjects were offered cognitive (computing) tests with new REG being recorded in the process. Thereafter the subjects warmed up and performed the proposed physical exercises under surveillance of an instructor. Immediately after the required static and dynamic loads, new REG were recorded at relative rest and in the cognitive test process. Rheographic study of the brain was performed by “Valenta”, a hardware and software diagnostic system by LLC “Neo Company”, Russia, in FM and OM that characterize the carotid and vertebrobasilar arterial systems, respectively.

Results and discussion. There was a statistically significant increase in the number of calculations in all the groups after the static and dynamic physical loads in comparison with the values prior to the loads. A decrease in the tone of the right and left distributing vessels, small arterioles and venules and a reduction in the peripheral vascular resistance in the carotid system were recorded in WLG during the cognitive test; these led to an increase in venous outflow in the left hemisphere by 2.6 times (p<0.05). However, a slight 1/3 increase in the arteriolar tone was recorded on the right side. Statistically significant changes were revealed in the vertebral arterial system on the left: increased blood filling of the vessels and venous outflow by more than 2 times in comparison with the background recording made immediately after the load. It should be noted that more pronounced changes in cerebral blood flow in WLG were found in the carotid system. 

An increase by 35% in the tone of large and medium-sized arteries on the right and on the left and of venous outflow by 2 times on the left were recorded in the carotid system of untrained young men after the static load. Similar changes were found in the vertebral arterial system against the background of a decrease in the arteriolar tone and general peripheral resistance by 25%. Thus, more pronounced changes were observed in the vertebral system of untrained young men after the static load. 

A 40% increase in blood filling on the right and on the left, a decrease in the tone of distributing and resistance vessels on the left and on the right and a decrease in the venular tone were recorded in the carotid system of TFG participants while they took the cognitive test, leading to an increase in venous outflow in the left hemisphere by 43.3% compared to the background recording after the load. A slight reduction (within the range of 15%) in the arteriolar and venular tone as well as in peripheral resistance was noted in the vertebral arterial system, which, however, did not lead to an increase in venous outflow.   

The most pronounced changes in the carotid and vertebral systems were observed in the left hemisphere. No statistically significant differences were found in the group of untrained young men performing the mathematical test with counting after a cyclic load compared with a background rheogram recording made immediately after the load. 

Destabilization of cerebral blood flow indicators against the background recording was less pronounced in the Track and Field Group of athletes compared to the Weightlifting Group while performing the cognitive test after the cyclic load on a cycle ergometer. Effect of various types of loads on the haemodynamic parameters is presented in Table 1. TFG athletes had a smaller increase in blood filling in the carotid system on the left while performing the cognitive test after the load (lower by 1/3 compared to WLG). A higher tone of large and medium-sized arteries was recorded in the right side of the carotid system of TFG athletes. Their distributing vessels tone decreased less significantly, and the tone of resistance vessels in TFG increased by 26%. Venous outflow in the left of the carotid system of WLG athletes increased more significantly; the same indicator in TFG is 2 times lower (similar changes took place in RG1 and RG2).        

In the vertebral arterial system changes in TFG are less significant than those in WLG. Tone of distributing vessels in the vertebrobasilar arterial system (both on the right and on the left) is higher in TFG compared to WLG, since the speed of fast vessels filling is lower in athletes of cyclic sports during cognitive test performance after exercise compared to that of weightlifters (by 29.7% on the left and 13.3% on the right) (p<0.05). In addition, a higher tone of resistance vessels is observed in vertebral arterial system on the left in TFG (the speed of slow vessels filling of track and field athletes is 39.3% lower than that of weightlifters).

Conclusion. Regular athletic training modifies the nature of haemodynamic support of cognitive and physical loads. The study demonstrated that the post-static-load cerebral haemodynamic variations were more expressed in the Weightlifting Group versus that in the Track and Field Group after the cyclic loads. Moreover, the physical loads were found to cause a stabilizing effect on the cerebral blood flow rates in cognitive process. The cyclic loads were found to create favourable conditions for the cerebral activity being more efficient. This can probably account for the fact that the results of the offered test in mathematics were higher in the group of athletes of cyclic sport disciplines.  

Table 1. Changes in cerebral hemodynamics against the background of cognitive and physical loads  

Group

Lead

Indicator

CT

PL

PL+CT

WLG

FMs/FMd

 

blood filling

tone of large and medium-sized arteries

arteriolar tone

venular tone

venous outflow

 

ОMs/OMd

 

blood filling

tone of large and medium-sized arteries

arteriolar tone

venular tone

venous outflow

 

RG1

FMs/FMd

 

blood filling

tone of large and medium-sized arteries

venous outflow

 

ОMs/OMd

 

blood filling

tone of large and medium-sized arteries

arteriolar tone

venular tone

venous outflow

 

TFG

FMs/FMd

 

blood filling

tone of large and medium-sized arteries

arteriolar tone

venular tone

venous outflow

 

ОMs/OMd

 

blood filling

tone of large and medium-sized arteries

arteriolar tone

venular tone

venous outflow

 

RG2

FMs/FMd

 

blood filling

tone of large and medium-sized arteries

 

ОMs/OMd

 

blood filling

tone of large and medium-sized arteries

venular tone

Note – the table shows statistically significant changes in the indices (р≤0.05); CT – cognitive test; PL – physical load; CT+PL – cognitive test after physical load.

Corresponding author: kapil@yandex.ru

 

Abstract

Objective of the study was to profile the cerebral blood flow variations in counting tests after the rated static and dynamic physical loads. Subject to the study were athletes of cyclic and acyclic sport disciplines (n=40, qualified at least Candidates for Master of Sport) split up into 2 equal groups, namely Track and Field Group (TFG) and Weightlifting Group (WLG). Two Reference Groups (RG1 and RG2) were composed of 40 university students qualified with the basic health group. All the subjects were 18-23 years old. Rheoencephalographs (REG) of the subjects were recorded at relative rest, and then the subjects were offered cognitive (computing) tests with new REG being recorded in the process. Thereafter the subjects warmed up and performed the proposed physical exercises under surveillance of an instructor. Immediately after the required static and dynamic loads, new REG were recorded at relative rest and in the cognitive test process.

The study demonstrated that the post-static-load cerebral haemodynamic variations were more expressed in the Weightlifting Group versus that in the Track and Field Group after the cyclic loads. Moreover, the physical loads were found to cause a stabilizing effect on the cerebral blood flow rates in cognitive process. The cyclic loads were found to create favourable conditions for the cerebral activity being more efficient.

References

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Corresponding author: kapil@yandex.ru

Abstract
Objective of the study was to profile the cerebral blood flow variations in counting tests after the rated static and dynamic physical loads. Subject to the study were athletes of cyclic and acyclic sport disciplines (n=40, qualified at least Candidates for Master of Sport) split up into 2 equal groups, namely Track and Field Group (TFG) and Weightlifting Group (WLG). Two Reference Groups (RG1 and RG2) were composed of 40 university students qualified with the basic health group. All the subjects were 18-23 years old. Rheoencephalographs (REG) of the subjects were recorded at relative rest, and then the subjects were offered cognitive (computing) tests with new REG being recorded in the process. Thereafter the subjects warmed up and performed the proposed physical exercises under surveillance of an instructor. Immediately after the required static and dynamic loads, new REG were recorded at relative rest and in the cognitive test process.
The study demonstrated that the post-static-load cerebral haemodynamic variations were more expressed in the Weightlifting Group versus that in the Track and Field Group after the cyclic loads. Moreover, the physical loads were found to cause a stabilizing effect on the cerebral blood flow rates in cognitive process. The cyclic loads were found to create favourable conditions for the cerebral activity being more efficient.