Dr.Biol., Associate Professor S.V. Pogodina1
PhD, Associate Professor V.S. Yuferev1
Dr.Med., Professor G.D. Aleksanyants2
1V.I. Vernadsky Crimean Federal University, Simferopol, Republic of Crimea
2Kuban State University of Physical Education, Sport and Tourism, Krasnodar
Keywords: physiological mechanisms, stabilization, functionality, active professional female athletes, involution age, prolonged high-intensity physical training.
Background. High-intensity physical training technologies are in the focus of interest of the research community . It was shown that involution-age women, whose physical activity is associated with dosed strenuous loads, are under the influence of cumulative effects allowing to maintain physical and esthetic rates of physicality at the level equal to that of youthful population [1, 2, 5]. In turn, as the female retirement age rose to 60 years, it became necessary to conduct a targeted study of physiological mechanisms aimed at the formation of compensatory-adaptive reserves and stabilization of functionality rates during involution.
Objective of the study was to identify the functionality stabilizing mechanisms in active professional involution-age female athletes.
Methods and structure of the study. Sampled for the study were the involution- (37-45 years old, n=18) and reproductive-age female athletes (16-26 years old, n=30), (MS, WCMS in running, swimming, cycling). The Control Group (CG) was made of untrained apparently healthy women (37-45 years old, n=18). The subjects’ physical development and working capacity were rated using anthropometry, dynamometry, spirometry, tonometry, cycle ergometry. We measured their body length (BL) and body mass (BM), wrist muscle strength (WMS,%), chest circumference (CC, cm) and chest excursion (CE, cm), vital capacity (VC), birth-death ratio (BDR, ml/kg =VC/BM), strength index (SI, % =WMS/BM), heart rate (HR, bpm), systolic blood pressure (SBP), double product index (DP, c.u. =SBPxHR), body mass index (BMI, g/cm =BM/BL). Physical working capacity was evaluated in the PWC170 and PWCAF tests, during which two types of load (W) of different power were performed (W1=65-75 W, HR 150-155 bpm, and W2=130-150 W, HR 165-170 bpm). Partial pressure of oxygen in the exhaled air (REO2, mmHg) was measured using the radio measuring gas analyzer PGA-KM, respiratory minute volume (VЕ, l•min-1) – using the spirometer (SPIROBANK G, Italy), with the rates being recorded during the last minute of W1 and W2 in the PWC170 test. Oxygen consumption (VO2, ml•min-1) was calculated by the formula VO2=VЕ х РЕО2 х1000/100, where is the PEО2 difference at W1 and W2. The subjects’ hormonal panel was studied by the method of enzyme-linked immunosorbent assay (semi-automatic immunoenzymatic plan-tablet photometer Stat Fax 2100, incubator shaker for 2 tablets Stat Fax 2200, Awareness Technology, USA) to determine the levels of estradiol, follicle-stimulating and luteinizing hormone (reagents Estradiol ELISA Kit, The Calbiotech, Inc CBI, USA, DS-EIA-gonadotropins-follicle-stimulating hormone, Gonadotropin EIA- luteinizing hormone, estradiol reference values of 10-370 pg/ml). The blood lactate level (La) was measured by means of the analyzer LACTATEPLUS Sports (USA) and test strips LactatePlus-TestStrips. The capillary finger-prick blood draws were taken using the safety lancets Safety. Nonspecific reactions were determined by the ratio of leukocytes in the leukogram. Vegetative provision was studied using the eight-channel tetrapolar rheograph RHEOCOM Standard (KhAI-MEDICA, Ukraine). Heart rate variability was assessed based on the short 5-minute ECG records and analysis of the following parameters: HR (bpm), standard deviation of NN-intervals (SDNN); number of pairs of cardiointervals with the difference of more than 50 ms in % of the total number of cardiointervals in the array (pNN50, n), ratio of high-frequency (HF) - 0.15-0.4 Hz, low-frequency (LF) - 0.04-0, 15 Hz, and very low frequency waves - 0-0.04 Hz. We studied the cardiohemodynamic indicators: stroke volume (SV, ml), minute blood volume (MBV, l/min), HR (bpm). The cycle ergometer step test was used as a stress test, in which the following work modes were modeled based on the load power (W) and intensity (HR) rates: aerobic (W1 - 50 W, HR - 130-140 bpm), aerobic-anaerobic (W2 - 100-120 W, HR - 150-160 bpm), anaerobic-aerobic (W3 - 150-220 W, HR - 170-185 bpm). The studies were carried out during the menstrual cycle (MC) - 1-3, 8-9, 13-16, 20-22, 26-27th days from the beginning of the MC. The statistical data processing was made using the STATISTICA 10.0 software. We calculated mean value - x, standard error – Sx; the significance of differences was determined using the Student's t-test. Where the data did not comply with the normal distribution law, the analysis was carried in terms of the median, minimum and maximum values - Me (min; max), interquartile range - IQR. The significance of differences was determined using the Wilcoxon t-test and the Mann-Whitney U-test.
Results and discussion. During involution, it is of primary importance to evaluate the degree of stability of the indicators correlated with the physiological function activity. The 37-45 year-old female athletes were found to have a significant increase of BMI to 348.22±3.89 g/cm as opposed to the 16-26 year-old ones – 306.75±4.71, p<0.01. At the same time, in both age groups, SI did not differ statistically significantly (60.37±4.27 versus 53.15±3.42, respectively, p>0.05), i.e., the increase of BM at the age of 37-45 years was not accompanied by intensification of muscle activity, which indicated decreased intensity of oxidative processes. Also, the 37-45 year-old female athletes demonstrated a significant decrease in BDR to 48.38±4.69 ml/kg, p<0.05. The DP index characterizing systolic work did not differ significantly between the groups and varied between 80.12±7.14 and 84.23±4.56 c.u., p>0.05. In other words, the 37-45 year-old women were characterized by the reduced aerobic and respiratory capabilities, while their myocardial reserves were at the level equal to that of the 16-26 year-old females. Nevertheless, there were no significant differences in the VO2 rate in the PWC170 test between the groups (in the 37-45 year-olds – 3398.37±17.10 ml•min-1 and in the 16-26 year-olds – 3240.08±14.79 ml•min-1, p>0.05) and, obviously, there should be mechanisms helping the 37-45 year-old female athletes with reduced aerobic and respiratory capabilities to maintain the VO2 rate at the level equal to that of the 16-26 year-old females. In the 37-45 year-old women, the CE rate was relatively high (8.21±1.12 versus 5.10±0.59 cm, p<0.05), which can be interpreted as a compensatory-adaptive mechanism supported by the high VO2 rate. The VO2 rate in the involution-age women, which was equivalent to that of young female athletes, was recorded in the lower intensity work mode W2 in the PWC170 test versus 16-26 years (1089.9±21.66 versus 1349.2±23.57 kg.m.min-1, p<0.05), which indicates more economical energy consumption and may contribute to high aerobic performance.
The aerobic capacity rates in the Control Group were at a relatively low functional level.
The analysis of the hormonal panel showed that in the 37-45 year-old female athletes, the follicle-stimulating hormone level on the 2nd-3rd day of MC was equal to 25.4±1.42 mIU/ml, and the luteinizing hormone level in the period from the 8th to the 27th day was 70.9±4.49 mIU/ml, which exceeds the threshold of the reproductive age norm. The estradiol level from the 13th to the 16th day of MC (Me [min; max]) was significantly lower in the groups of involution-age women as opposed to the 16-26 year-old ones (in the 37-45 years-olds – 93 (83; 97.55), in the untrained 37-45 year-olds – 53.1 (42; 206.8), in the 16-26 year-olds – 103.8 (50; 183.3), p<0.05), which reduces the possibility of ovulation. The estradiol levels in the involution-age women varied considerably . The 75/25% IQR values in the 37-45 year-old female athletes indicated a relatively lower level-rated differences in this hormone level (in the 37-45 year-old female athletes - 75/25% IQR=48, in the Control Group – 75/25% IQR=138) and greater effectiveness of adaptive mechanisms of steroidogenesis, which balances the estrogenic profile.
The study of the level of non-specific resistance determined the formation of the non-specific calm activation response in the female athletes aged 37-45 years during MC (lymphocytes within the range from 27.95±0.61 to 30.34±0.69 %, p0.05). In the female athletes aged 16-26 years, there were non-specific activity fluctuations from training reactions to increased activation response (lymphocytes in the range of 26.82±1.36-34.94±0.26%, p<0.05). The activity of non-specific mechanisms was formed with different dynamics of accumulation of the fatigue control metabolic factors. In the groups of female athletes, we observed the achievement of the anaerobic threshold in the work mode W1 (La in terms of Me (min; max) within the limits of 4 (2; 4) mpm/l, p>0.05). The increase of work intensity in the mode W2 determined the increase of La to 6 (4; 6) mmol/L, p>0.05. In the high-intensity work mode W3 there was no statistically significant increase of La in the 37-45 year-old female athletes (in the 37-45 year-olds - La=8 (0.5; 10) mmol/L, p>0.05; in the 16-26 year-olds - La=8 (6; 13.5) mmol/L, p<0.01).
Considering that the fatigue control metabolic factors enhance the response from the central nervous system and increase the energy "cost" of adaptation ; it should be noted that the latter decreased in the 37–45 year-old women. In the Control Group, we observed high-intensity training reactions, high La rate in terms of Me (min; max) in the low-intensity modes (W1 La=6 (5; 6) mmol/L; W2 La=9 (6; 9.5) mmol/L, p<0.01; W3 La=8 (2.5; 8) mmol/L, p<0.05).
The analysis of heart rate variability in the initial state showed that during MC the differences in the SDANN values reflecting integral neurohumoral regulation of cardiac activity were insignificant in the 37-45 and 16-26 year-old female athletes (46.8±2.09 - 70.2±3.00 and 46.5±1.32 - 69.6±2.24, p0.05). The range of the SDANN values in the Control Group was comparatively lower (26.5±1.83 - 60.1±2.43, p<0.05). We found significant differences in the pNN50 values: in the 37-45 year-old female athletes they ranged from 8.5±4.66 to 17.0±1.66%, in the Control Group – from 15.0±1.20 to 3.07±0.2, p<0.05, and in the 16-26 year-old ones – from 17.4±2.76 to 42.1±3.22% (p<0.01), which indicates a decrease in parasympathetic influences by the age of 37-45 years. The spectral analysis revealed that the power of the low frequency and high frequency waves in the groups of female athletes was equivalent (the LF-waves in the 37-45 year-old women – 1719.6±16.26 - 480.0±3.52 ms2, in the 16-26 year-old ones – 1666.8±18.20 - 453.23±8.69 ms2, p0.05; the high frequency waves in the 37-45 year-old women – 2428.6±19.50 - 477.5±7.65 ms2; in the 16-26 year-old ones – 2065.9±14.8 - 591.37±16.95 ms2, p0.05). The power of the very low frequency waves was significantly lower in the 37-45 year-old females (37-45 year-olds – 888.8±7.74 - 376.3±6.80 ms2, in the 16-26 year-olds – 1581.8±17.66 – 1055.94±19.56 ms2, p<0.01), which was associated with the decrease of centralization of heart rate control in the former. In the Control Group, the power of the low and high frequency waves was significantly lower (the LF-waves – 1402.9±11.36 - 332.2±9.76 ms2, p<0.05; the high frequency waves – 1691.1±12.64 - 208.7±4.86 ms2, p<0.05), and significantly higher in the spectrum of very low frequency waves (VLF-waves – 1065.65±11 - 561.1±12.24 ms2, p<0.05). When working in the high-intensity work mode W3, there was a significant decrease in the power of the very low frequency waves and an increase in the high frequency waves in the studied groups from the 8th to the 27th day of MC, which increased the reserves of autonomous regulation. In the Control Group, we observed an increase in the power of the very low frequency and low frequencywaves.
The analysis of cardiac hemodynamics in the W3 work mode determined the subjects’ cardiac reserve. The MBV and SV rates during MC did not differ statistically significantly (MBV in the 37-45 year-old women ranged between 14.6±0.66 - 16.9±0.56 l/min; in the 16-26 year-old women – between 14.6±0.43 - 13.8±0.89 l/min, p0.05; SV in the 37-45 year-old women ranged between 88.2±1.20 - 96.6±3.11 ml; in the 16-26 year-old women – between 81.4±1.59 - 96.8±3.92 ml, p0.05). The contribution of HR to the increase of MBV during MC was identical in the studied groups (in the 37-45 year-old women – 123.32±6.14 - 130.71±2.43%; in the 16-26 year-old women – 118.78±4.24 - 141.35±6.75%, p0.05). The contribution of SV to the increase of MBV in the 37-45 year-old female athletes was significantly higher and ranged between 19.09±1.02 - 26.9±2.27 %, while in the 16-26 year-old women the maximum stroke volume index reached 17.05±2,68 %, p<0.05. In other words, the 37-45 year-old female athletes achieved the same MBV level as at the age of 16-26 owing to greater cardiac activity. In the Control Group, we detected low efficiency of the vegetative support of activity, a significant increase in the power of the low and very low frequency waves, a pronounced decrease of SV below the initial level.
Conclusion. It was found that the prolonged high-intensity physical trainings of involution-age women result in the high level of aerobic performance maintained by optimization of the pulmonary mechanics, suppression of the fatigue control metabolic factors and adaptation cost reduction. The hormonal and vegetative balance is further maintained by the self-control mechanisms geared to stabilize the estrogens, activate the relevant autonomous nervous system mechanisms and mobilize the circulation control in the cardiovascular system.
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High-intensity physical training technologies are in the focus of interest of the research community. The article analyzes the involution-age female athletes’ functionality stabilizing mechanisms activated by long high-intensity physical trainings. The study was designed to profile the adaptation processes in the 37-45 year old and 16-26 year old sporting women groups versus the 37-45 year old unsporting group by anthropometrical characteristics, dynamometric tests, respiratory function test, gasometric method, immunity test, biochemical, hematological, blood flow (rheographic), ergometric tests and the standard statistical data processing tools. It was found that the prolonged high-intensity physical trainings improve the involution-age women’s functionality test rates to the level of the 16-26-year olds, albeit the functionality reserves are still depleted to a degree. High performance standards are further maintained by the compensatory adaptation mechanisms, particularly in the high-intensity trainings. Aerobic performance standards are maintained by suppression of the fatigue control metabolic (lactate related) factors plus more economic respiration process control and adaptation cost reduction mechanisms. The hormonal and vegetative balance is further maintained by the self-control mechanisms geared to stabilize the estrogens, activate the relevant autonomous nervous system mechanisms (to strengthen the parasympathetic effects) and mobilize the circulation control in the cardiovascular system.