Seasonal evaluation of skeletal muscle damage and hematological and biochemical parameters of Greco-Roman wrestlers from the Kyrgyzstan National Team before the 2016 Summer Olympic Games

1. Introduction

Physical and physiological capacities evolve clearly with regular activities [1]. It has been shown that like many other factors hematologic parameters play an effective role in the correction of physiological consequences such as adapting to activity, adapting cardiovascular activity and physical and physiological balance [2, 3]. In some studies it has been reported that it has positive effects on physical, physiological, psychological and motoric properties of activities [4, 5, 6, 7]. It is stated that exercise occurs stress on the human body and there are various physiological and metabolic effects in this stress. One of these effects is the changes occurred in blood. It is determined that the most important effect of the regular activities is in the blood cell. Because when the blood cell is examined, it is seen that the regular activities effects on the blood cell levels are not the same as the other effects. These differences may be related to the physical, physiological, and conditioning properties of the subjects participating in the study, as well as changes in hematological parameters and the type, severity, and duration of the exercise. It has been reported that hematologic changes at the moment of severe activity and subsequently in individuals occur due to long-term activities as well as factors such as exercise status, gender, age, environmental factors and eating habits [1, 8]. It is also said that there are different findings related activity regarding to the level of blood biochemistry. Besides the studies indicating that positive developments occur as an acute exercise result in the biochemistry of blood, there are also studies that report that changes occur after chronic exercises [1]. It is observed that at the moment of activity some fluid is separated from the veins and spreads among the tissues and thus erythrocyte, hemoglobin and intensity of plasma proteins in blood increase [9]. In the activity, as a result of increasing and accelerating the blood flow, the leukocytes which adhered to the wall of veins will accompany the blood flow and therefore the leukocyte ratio can increase. Studies also report that hormonal changes also play a role in this increase [10, 11]. “The greater the rate of inclusion in the activity, the greater the rate of leukocyte increasing” is also seen. This increase can be seen more clearly in dense activities. The primary cause of this increase is reported as the increasing of blood pressure while activity and therefore increasing the fluid filtration among the tissues by the arterial of the capillaries. Another reason is determined as the increase of the osmotic pressure which occurs as a result of increasing in metabolism and therefore increasing of the metabolizing substances in the interstitial fluid and thus the withdrawal of the fluid among the tissues [12].

It has been reported that the amount of hematocrit and hemoglobin decreased in sportsmen who are exposed to intense activity program and this situation is also evaluated as sportsman’s anemia. It is stated that in a study the subjects were instructed to perform two hours running training that resulted in a 4% reduction in their body weight and 9.6% decrease in blood volume, while in plasma volume 12.2% decrease and in erythrocytes 6.3% decrease has been determined. On the contrary, there are also studies that have not found a change in the volume of erythrocytes. It is reported that hematocrit is found as 42–50% in normal males and 37–47.1% in females. It is known that many researches have been done on how exercise affects hematological parameters. In addition to being affected by blood parameters by the type and intensity of activity, activity affects blood parameters and is important for various blood pathologies. It is observed that acute submaximal activity significantly increased erythrocyte, hematocrit (Hct), hemoglobin (Hb), leukocyte and platelet values in comparison with the results before exercise and it is reported that the cause of this increase is the loss of plasma caused by activity. It is seen that the activities which shortened their duration until reaching to tiredness increase the leukocyte amounts and this state cannot be described only by the mechanism of hemoconcentration and the metabolic changes occurring during the activity may be related to this [13]. Similarly, it has been specified that acute submaximal activity increases leukocyte parameters and this activity is directly proportional to intensity [14].

In case of increasing thrombocyte levels which follow acute submaximal activity, the bleeding and coagulation times are reduced [15]. Relevant studies report that although these differences in blood values occur later, these differences have reached the level of rest within 24 hours after activity [16].

A wide variety of research has been carried out to determine the physical and physiological properties and capacities of athletes in different sports branches and to determine more subjects. The sports branches in which weight is important, and wrestling in particular, wrestlers usually prefer to lose weight before the competition to compete in a lower cycle. To provide this criterion, athletes reduce their fluid consumption to the lowest level before the competition and during the training. In this process, they sometimes avoid consuming liquids for days during training, until the competition debate. It is known that doing exercise without consuming liquid has negative effects on the blood values. This situation causes dehydration and affects the athletes’ performance negatively. From this point of view, we aimed to evaluate some hematological and biochemical parameters of the Greco-Roman wrestlers who constitute Kyrgyzstan National Team within six months.

2. Materials and methods

The hematological parameters of Greco-Roman style wrestlers can be found in Table 1. As can be seen, the total leukocyte, lymphocyte and neutrophil counts after exercise were significantly increased ( 0.05) in all three measures (beginning, 3rd and 6th months). Pre-and post-exercise changes in other hematological parameters have not been found statistically significant ( $p>$ 0.05, Table 1). No statistically significant difference was found between pre and post-exercise values of all three measures ( $p>$ 0.05).

The biochemical analyses of the Greco-Roman style wrestlers can be found in Table 2. As can be seen, blood glucose levels significantly decreased after exercise compared to pre-exercise levels in all three measures (beginning, 3rd, and 6th months). After exercise, HDL cholesterol concentrations significantly increased ( 0.05), while LDL cholesterol concentrations significantly decreased ( 0.05) (Table 2). Other biochemical parameters, pre- and post-exercise changes have not been found statistically significant ( $p>$ 0.05, Table 2). There was no statistically significant difference in three measures applied on athletes between pre-exercises (Table 2) and post-exercise ( $p>$ 0.05).

4. Discussion

There may be changes in hematological parameters of living creatures depending on the type, severity, and duration of exercise. In the study, leukocyte, lymphocyte and neutrophil counts after exercise in all three measurements of Greco-Roman wrestlers (beginning, 3rd, and 6th months) were significantly increased compared to values before exercise. Other hematological parameters changes before and after exercise were not statistically significant. Bezci and Kaya have reported that the values of WBC, HGB, PLT, RBC, HCT, and MCH were significantly increased before and after training in female Taekwondo athletes and there was no significant difference in MCV and MCHC values. It is also stated that these changes are within the physiological limits and therefore do not pose any risk to the athletes [17]. Ersöz has investigated the effect of 15 minutes acute submaximal exercise applied on 23 healthy sedentary individuals between the ages of 18–24, on measures thrombocyte functions made before, immediately after and 1 hour after exercise. As a result of the study, it was observed that thrombocyte and erythrocyte counts and hematocrit values did not change with the applied exercise program and the number of leukocytes which increased by exercise, decreased to normal values 1 hour after the end of the exercise. It has been reported that 15 minutes of physical exercise increased aggregation and secretion in thrombocyte without significantly altering thrombocyte counts [18]. Patlar has stated that acute and 4-week chronic exercises administered to healthy men cause a significant increase in leukocyte counts [19]. Many studies have reported that intensive exercise increases leukocyte concentration [20, 21] and in addition to this increase the condition of the person is also a determining factor [22]. In a study examining the effects of exercise on WBC values, a significant increase has been found in the number of locusts on 25-year-old athletes during and after acute exercise [20]. Katsuhiko et al. found significant increases in the total loco-positivity and leucocyte ratios of long-distance running athletes at the age of 32 years after a marathon race [23]. In another study by Monya et al., it was determined that vigorous submaximal exercises lead to a significant increase in the number of locusts of sedentary men [24]. Green et al. found significant increases in loco-counts at the end of a 30 and 60-minute endurance run of 33 years old well-trained athletes with an hourly speed of 14 km. The results of the above-mentioned research are important with regard to be similar to our study results [25]. The increases of leukocyte counts in post-exercise may be due to hemoconcentration; [12, 26] mechanism or leukocytes which are specified as demagnetization and adhere to the vessel wall as blood flow increases during exercise [27]. It was also found that acute high-intensity exercises causes great stress on the organism and there may be significant increases in leukocyte counts in response to some hormonal changes [18]. The greater the stress associated with the exercise, the greater the amount of increase in leukocyte. This increase is especially significant in severe exercises. The main reason of this increase is the increase in blood pressure during exercise, and thus the increase of fluid filtration among the tissues by the capillaries. Another reason is the increase of the osmotic pressure as a result of the increase of metabolism products with the increase in metabolism rate in the interstitial fluid and therefore spreading the fluid among the tissues [9]. Yeh et al. reported that there were no significant changes in athletes’ RBC concentration within 12-weeks of regular exercise [28]. There was no significant change in MCV, MCH, MCHC values before and after the program in gymnasts subjected to 10-week exercise [29]. Similarly, Rietjens et al. reported that there was no change in MCV, MCH, MCHC before and after the season in a study they applied to 11 Olympic athletes [30]. Ghanbari and Tayebi have stated that the acute circuit resistance training they applied to 20 sports department students showed a significant decrease only at MCV level, but not at the level of PLT, PDW, MPV, P-LCR, RBC, HGB, MCH parameters [31]. El-Lithy et al. examined the effect of chronic aerobic exercise on hematological parameters on 30 premenstrual women with ages ranging from 16 to 20 years and found significant increases in HGB, HCT, and RBC levels in aerobic exercises performed three days a week during three months. However, the same significant effect was not seen at MCV, MCH and MCHC levels [32]. In another study it was found that high-intensity (HIT) training for three weeks did not significantly increase hemoglobin, blood and plasma volume levels of male and female athletes [33]. Moon et al. reported that acute submaximal (70% MHR) bicycle exercise in 11 healthy subjects under hypoxic conditions did not lead to significant changes in the number of erythrocytes, hemoglobin counts, and hematocrit levels [34]. The report of Yeh et al. determined that 14 male and 23 female athletes who regularly performed exercises for 12 weeks did not show any significant change in RBC levels at 12 weeks, despite of their gender difference. This is an important overlap with the result of our study [28].

In our study, wrestlers’ glucose levels had significantly decreased after exercise compared to before exercise in all three measures (beginning, 3rd and 6th months). However, no difference was observed between pre-exercise and post-exercise in the measurements performed at 3-month intervals. Oxidation of glucose increases several times with exercise. In such cases, when the blood glucose level decreases, the blood glucose level is increased by releasing the glucagon hormone. As exercise continues, the usage of glucose by muscle will be increased 7–20 times depending on the severity and duration of exercise and blood glucose becomes a primary energy source. In mildly severe exercises blood glucose levels do not change so much while in heavy exercises it will be increased at the rate of 15–20% [35]. If the exercise is severe, long-term blood glucose falls below normal resting values due to a decrease in liver glycogen. In our study, the levels of blood glucose decreased significantly after the fatigue exercises. However, there are also studies that indicate that blood glucose levels increase after exercise. As a matter of fact, Zeinali et al. have reported that blood glucose levels will be increased after exercise in acute aerobic exercises in sportsmen [36]. In have reported the similar results in marathon runners [37, 38]. It can be said that the method of studying this difference may be due to the difference in duration and intensity of exercise and the subjects.

After the severe aerobic training period, triglycerides decrease, total cholesterol sometimes decreases and sometimes does not change but the high cholesterol (HDL cholesterol) level increases and low cholesterol (LDL cholesterol) level decreases [39]. Çakmakçı et al. have stated that total cholesterol level decreased significantly after intensive training in female Taekwondo athletes and did not the cause significant change in triglyceride level [40]. A significant decrease in cholesterol level and no difference in triglyceride levels may be due to the increased lipoprotein lipase association in muscle and fat during exercise and the use of blood lipids and free fatty acids in energy expenditure. In a study conducted on 20 metabolic syndrome and 10 sedentary individuals, only subjects with metabolic syndrome had moderate-intensity cycling exercises of 45 minutes which was carried out 3 times a week for 3 months. At the end of the study, as a result of 3 months exercise there was no significant change in plasma HDL cholesterol levels and a significant decrease in total triglyceride levels was determined [41]. Another research stated that there was no significant change in the serum triglyceride, total cholesterol, and LDL-cholesterol ratios after exercise, and HDL-cholesterol level has significantly increased in the subjects to whom Fox’s maximal cycling ergometer test has been applied [42]. It was reported that serum HDL cholesterol levels increased significantly in sportsmen who do exercise regularly and triglyceride, total cholesterol, and LDL cholesterol levels did not change much. Although there was a significant increase in HDL cholesterol levels after exercise in three measures in all branches of this study, it was concluded that exercise had a direct effect on HDL cholesterol level and other lipid parameters had limited effect on the other lipid parameters [43]. The findings of this research are in line with the previous studies.

In the conducted study, the levels of total protein, urea and creatinine were not statistically significant in all three measures (beginning, 3rd, and 6th months) after exercise compared to before exercise. The same similarity was obtained in measurements performed in 3-month periods. As a matter of fact, a research divided 20 male students aged 15–18 years into two groups, one group exercised aerobic exercise with 65–75% of maximal heart rate and the second group applied 1000 m interval exercise with three repeat cycle. There were no differences in total protein, urea and creatinine levels before and after exercise at the end of the application. However, the total protein, urea, and creatine levels of the interval training group increased significantly compared to the aerobic exercise group [44]. Similarly, as a result of a study that was performed on athletes, aerobic exercises did not affect skeletal muscle protein synthesis as much as resistance exercises [45]. It is important to mention that these studies are similar to our study.

In the current study, it was determined that CK levels, which increased after exercise compared with before exercise, were not statistically significant in all three measurements. Unlike our study, another a studied associated semi-professional footballers’ high CK values after a soccer match with muscle damage [46]. Similarly, many studies have reported that pre-and post-training measures increased their CK values favorably after exercises [47, 48]. In a different study, a significant increase in CK rates after a 10-minute submaximal run was also found, rather than before running [49]. Another study found that serum CK levels of marathoners were 21 times higher after running than before [50]. The high CK values after exercise mentioned in the above literature are different from the CK values obtained after the competition in our study. It can be said that this difference is related to the duration and severity of exercise. It is thought that this partial non-statistical semi increase in the study we performed may be a sign of muscle damage.

Lactate dehydrogenase (LDH) is a cytoplasmic enzyme that converts lactic acid to pyruvic acid. Since the levels of intracellular LDH are 500 times higher than those of serum, the slightest increase in serum is an indication of cell damage [51]. In the study, it was determined that LDH levels increased slightly after exercise compared to before exercise in all three measures and this increase was not statistically significant. Especially eccentric exercises are reported to cause significant increases in LDH levels [52]. As a matter of fact, in a study in which eccentric exercise has been applied on humans for 6 days, significant increases were found in LDH levels after the 3 rd day. In another study, it was also found that although LDH levels were significantly increased during normal and intensive exercise in Tai-boxing athletes, LDH levels in the blood samples taken 12 hours after the exercise were close to basal level [53]. Very prominent increases in LDH levels were identified in very long-running athletes (245 km). In these athletes, the pre-race value was 373 U/L and it reached to 2299 U/L after the race. The increases in blood LDH levels in exercise can be a result of cell damage and depletion of cells’ energy resources that occur after long-term exercises, which causes the increase in membrane permeability of muscle cells. Increases in serum total LDH levels are a result of one or more increase(s) in enzyme fractions in tissues where LDH isoenzymes are intensively found [54]. The insignificant increase in LDH levels in our study is contradictory to the literature. It can be said that this may be due to adapting the desire of Kyrgyz National Team Greko-Roman wrestlers to this exercise intensity.

5. Conclusion

Fatigue exercise in all three measurements has significantly increased the total leukocyte, lymphocyte and neutrophil values of the wrestlers, while it has not affected other hematological parameters. Fatigue exercise has also significantly reduced blood glucose levels and LDL cholesterol concentrations, while it has increased HDL cholesterol levels. It did not show any significant effect on other biochemical parameters. The six-month training did not have a significant effect on both hematologic and biochemical parameters in all three measurements.