PhD, Associate Professor E.N. Minina¹
PhD, Associate Professor N.S. Safronova
Dr. Med., Professor A.G. Lastovetsky²
PhD, Associate Professor V.V. Minin¹
¹Vernadsky Crimean Federal University, Simferopol
²Research Institute for Organization and Informatization of Healthcare of the Ministry of Health of the Russian Federation, Moscow

Keywords: cardiorespiratory system, hypocapnia, functional reserves.

Background. Constant psychophysical stresses in qualified athletes often lead to the overstrain of the functional systems of the body, especially the cardiorespiratory system, which increases the risk of failure of adaptation and reduced working capacity (A.V. Mikhaylova, 2009). Therefore, timely diagnostics and correction of the resultant dysfunctional conditions make it possible to preserve the athlete’s health and high fitness level. As known, excessive pulmonary ventilation is a factor that limits efficiency of the muscle activity and may cause tension in the cardiovascular system  (N.A. Aghajanyan, 2000). Consequently, a differentiated approach based on the analysis of divergences of different parameters of the cardiovascular and respiratory systems is essential in the planning of the correctional impacts.

Objective of the study was to substantiate the need for a differentiated approach to the correction of the functional state of qualified athletes using hypoxic-hypercapnic training.

Methods and structure of the study. The study was carried out at the premises of the state-financed institution "Sports Medicine Center", Crimea, in the period from 2015 to 2017, with the informed consent of the subjects and after the verdict of the ethics committee. Sampled for the study were the 19-22 year-old qualified athletes from team sports (n=100) and combat athletes (n=100). The authors rated their cardiorespiratory system functionality in the transitional period of the one-year training cycle, which was followed by the hypoxic-hypercapnic training course for 83 athletes. The course consisted of 10 training sessions, each with three sets of 5, 6, and 7 minutes (18 minutes in total), respectively, with a 5-minute rest break inbetween.

Results and discussion. We defined the specifics of the respiratory patters in the athletes by the carbon dioxide content in the last portion of the exhaled air (Table 1).

No differences were observed between the team athletes and combat athletes in terms of the distribution of the hypocapnic and normacapnic types of lung ventilation. At the same time, the normacapnic type of ventilation was typical of more than 50% of the subjects in both groups.

Table 1. T-wave symmetry rates (β_T) in primary survey of qualified athletes depending on type of lung ventilation

Conspicuous is the fact that the hypercapnic type of ventilation was more typical of the combat athletes than of those from team sports – the difference was twice as big (p˂0.05). In the hypocapnic subgroup, the T-wave symmetry rate (β_T) was significantly higher compared with the normacapnic subgroup regardless of the focus of the training process. Thus, the degree of reduction of the cardiac reserves in the second subgroup of team athletes was the highest – 22% (p˂0.01) as opposed to the first subgroup. A less pronounced difference of 18% (p˂0.05) was observed in the third subgroup. Among the combat athletes, the rates of reduction of the functional reserves of the myocardium in terms of β_T were as follows: 17% and 15% (p˂0.001) in the hypocapnic and hypercapnic subgroups respectively as compared to the normacapnic subgroup. The correlation relationship between P_ETCO₂ and MOC/kg in the team athletes with the normacapnic type of lung ventilation was at the level r=0.63 (p˂0.01), while in the other two subgroups, the correlation was not statistically significant. A similar correlation analysis revealed a correlation between P_ETCO₂ and MOC/kg in all subgroups of combat athletes: r=0.71 (p˂0.01) in the first and second subgroups and r=0.77 (p˂0.001) in the third one The hypocapnic subgroup subjects were found to have the low levels of physical working capacity and aerobic capacities. At the same time, their MOC/kg rates did not exceed 48 ml/min/kg. The identified patterns indicated the need to differentiate athletes by the lung ventilation type to take further corrective actions aimed to increase the myocardial reserve and aerobic potential of the body.

The respiratory training had the most positive effect on 47 (92%) out of 51 athletes with initial hypocapnia. Their breathing pattern changes towards an energy-efficient reduction of the respiration rate: by 20.2% (p<0.05) at rest and by 25% (p<0.01) under the physical load of 250 W. Against this background, an increase in the myocardial reserves and aerobic capacities was observed. Thus, the β_T value decreased by 6% (p˂0.001), while the MOC/kg rate increased by 10% (p˂0.01) (Table 2).

Table 2. Dynamics in P_ET CO₂, MOC/kg and β_T rates in qualified athletes depending on lung ventilation type before and after respiratory training course (M±SX), n=200

Note. Significance of differences in the test rates before and after the respiratory training course.

In 30 (92%) out of 32 athletes with initial hypercapnia, the transition to the normacapnic ventilation was accompanied by a reduction in the level of tension of myocardial contractility regulation mechanisms, which was recorded by means of phasometry characterizing cardiac electrical activity. It was found that the β_T value decreased by 10% (p˂0.001). It should be noted that an upward trend was observed in the MOC/kg rate; however, the changes were statistically insignificant.

Conclusion. The CO₂ content in the last portion of the exhaled air and the phasometric rate can act as markers of the mechanisms that determine the athlete’s aerobic potential. Obviously, the respiratory training should be planned and conducted employing a differentiated approach based on the type of lung ventilation.

References

1. Aghajanyan N.A., Bayevskiy R.M., Berseneva A.P. Doctrine of health and problems of adaptation. Stavropol, 2000. 173 p.
2. Minina E.N. New approach to studying relationship between functional fitness and electrogenesis in athletes using reference cardiocycle. Vestnik novykh meditsinskikh tekhnologiy. Electronic edition. 2014. No. 1. Publ. 1-8. Available at: http://medtsu.tula.ru/VNMT/Bulletin/E2014-1/4931.pdf. (Date of access: 15.05.2020).
3. Minina E.N., Bukov Yu.A., Belousova I.M. Device for interval hypoxic-hypercapnic training of human body: utility model patent No. 158989 (Russian Federation), applicant and patentee. Vernadsky Crimean Federal University, publ. 20.01.2016, Bul. No. 2.
4. Mikhaylova A.V., Smolenskiy A.V. Sports heart overstrain. Lechebnaya fizkultura i sportivnaya meditsina. 2009. No. 12 (72). pp. 26-32.
5. Fainzilberg L.S. Computer diagnostics based on phase portrait of electrocardiogram. Kiev: Obrazovanie Ukrainy, 2013. 190 p.
6. Aksenov M.O., Andryushchenko L.B. Myostatin gene role in strength building process. Teoriya i Praktika Fizicheskoy Kultury, (4), pp. 71-73.
7. Al-Khelaifi F., Yousri N.A., Diboun, Semenova E.A., Kostryukova E.S., Kulemin N.A., Borisov O.V., Andryushchenko L.B. Genome-Wide Association Study Reveals a Novel Association Between MYBPC3 Gene Polymorphism, Endurance Athlete Status, Aerobic Capacity and Steroid Metabolism Frontiers in Genetics,Volume 11, 16 June 2020, 595.
8. Andryushchenko L.B., Ahmetov I.I., Borisov O.V., Generozov E.V., Pickering C., Semenova, E.A., Andryushchenko, O.N. Team Sport, power, and combat athletes are at high genetic risk for coronavirus disease-2019 severity. Journal of Sport and Health Science Volume 9, Issue 5, September 2020, Pages 430-431.
9. Masalimova A.R., Mikhaylovsky M.N., Grinenko A.V., (...), Kochkina M.A., Kochetkov I.G. The interrelation between cognitive styles and copying strategies among student youth. Eurasia Journal of Mathematics, Science and Technology Education 15 (4), em1695.
10. Pushkareva Y.E., Elrayess M.A., Andryushchenko L.B., Semenova E.A., Miyamoto-Mikami, E., Akimov E.B., Al-Khelaifi F., Murakami H. Zempo H., Kostryukova E.S., Kulemin N.A., Larin A.K., Borisov O.V., Miyachi M., Popov D.V., Boulygina E.A., Takaragawa M., Kumagai H., Naito H., Pushkarev V.P., Dyatlov D.A., The association of HFE gene H63D polymorphism with endurance athlete status and aerobic capacity: novel findings and a meta-analysis. European Journal of Applied Physiology 2020.

Corresponding author: andryushenko-lil@mail.ru

Abstract

Objective of the study was to substantiate the need for a differentiated approach to the correction of the functional state of qualified athletes using hypoxic-hypercapnic training.

Methods and structure of the study. The study was carried out at the premises of the state-financed institution "Sports Medicine Center", Crimea, in the period from 2015 to 2017, with the informed consent of the subjects and after the verdict of the ethics committee. Sampled for the study were the 19-22 year-old qualified team athletes (n=100) and combat athletes (n=100). The authors rated their cardiorespiratory system functionality in the transitional period of the one-year training cycle, which was followed by the hypoxic-hypercapnic training course for 83 athletes. The course consisted of 10 training sessions, each with three sets of 5, 6, and 7 minutes (18 minutes in total), respectively, with a 5-minute rest break inbetween.

Results and conclusions. When identifying the differences in the functional reserves of the myocardium, it was the T-wave symmetry rates (β_T) that were the most informative. There were statistically significant relationships between MOC/kg and P_ЕТCO2 in the combat athletes with all breathing patterns. After the hypoxic-hypercapnic training course, the initial hypocapnic athletes were found to have expanded myocardial reserve and increased aerobic capacity of the body. The β_T value decreased by 6% (p˂0.001), the MOC/kg value increased by 10% (p˂0.01). In the group with the initial hypocapnic type of ventilation, no changes in MOC/kg were found, but the β_T value decreased by 10% (p˂0.001).