PO-068 Influence of different intensity exercise on immune factor in the hot and humid environment

Objective  to study the influence of exercise on immune factor IL-2、IL-3、IL-6 in the hot and humid environment by comparing the changes of leukocytes after different intensity exercise with the normal environment，exploring the training program which is beneficial for the immune system in the hot and humid environment, and supply the theoretical basis for the sports training and National Physical Fitness in the hot and humid area. Methods The experimental subjects were 32 healthy male college students of Guangzhou Sports with an average age of 20.9 years. All the subjects tested the maximum oxygen uptake before the experiment, and then were divided into the control group, the 55%VO2max sports group, the 70%VO2max sports group and the 85%VO2max sports group. The experimental subjects took a treadmill running in the normal environment(20-25℃;RH: 55-60%) and finished the same exercise training program in the hot and humid environment(30-32℃；RH：90-95%) after a week, collected the elbow venous blood before and after exercise in the normal environment, The main test indicator contained IL-2、IL-3 and IL-6, Training program: control group sit quietly for 30 min;  The 55%VO2max group: Movement×2, 15min one time, Interval 5 min; The 70% VO2max group: Movement×3, 10min one time , Interval 5 min; The 85%VO2max group: Movement ×4, 7.5 min one time , Interval 5 min; All data were calculated using SPSS 25.0, Mean + / - standard deviation (Mean + / - SD), paired T test, single factor variance and multifactor variance analysis. P<0.05 was the significant level, and P<0.01 was the very significant level. Results 1、IL-2 is mainly produced in activated T lymphocytes, which can promote T cell proliferation, improve the secretion and function level of NK cells, play an important role in immune regulation and is an important regulatory factor. Under normal circumstances, IL-2 of the body of each exercise group increased slightly after acute exercise, but there was no statistical significance (p>0.05). In the humid and hot environment, IL-2 decreased in all groups after exercise, and the decrease in the quiet group was large, but there was no statistical significance(p>0.05).2、IL-3 is a multipotent hematopoietic regulatory factor that ACTS on the proliferation and differentiation of hematopoietic cells, mainly produced by activated T lymphocytes. Under normal circumstances, the IL-3 increase of 55% VO2max and 85% VO2max group was not obvious after exercise, while that of 70% VO2max group was not obvious before and after exercise. After acute exercise in hot and humid environment, IL-3 increased in all groups, but there was no statistical significance(p>0.05). Compared with the normal environment, IL-3 increased after exercise in each group.3、IL-6 plays an important role in the regulation of motor mediated function, known as kinematic factor, mainly from stimulated mononuclear macrophages, fibroblasts and vascular endothelial cells. Skeletal muscle can also express IL-6 under exercise stress, which is involved in the repair of muscle cell injury and plays an important regulatory role in skeletal muscle metabolism. Under normal circumstances, after exercise, there was a significant increase in all the exercise groups, among which 55% of the VO2max group and 70% of the VO2max group had a significant difference in IL-6 before and after exercise (p<0.05), and 85% of the VO2max group had a very significant difference (p<0.01). In the humid and hot environment, IL-6 increased after thermal stress in the quiet group, and IL-6 increased significantly after acute exercise in all the exercise groups (p<0.01). Compared with the normal environment, IL-6 increased more significantly and significantly in each group after exercise. Conclusions  The combined effect of heat stress and exercise stress on human immune function in the thermal environment is more significant than that of heat stress or exercise stress alone. The greater the intensity of exercise, the decrease of IL-2 and the significant change of IL-6, the more attention should be paid to the temporary immunosuppression caused by excessive intensity of exercise in the humid and hot environment

PO-066 The Function of t Lycium Barbarum Juice Supplemen in Exercise Stress Regulation during Increasing Resistance Training

Objective The purpose of this study was to explore the function of Lycium Barbarum juice on exercise stress regulation when male university students drank Lycium Barbarum juice during increasing resistance exercise, by observing the effects of oral Lycium Barbarum juice on the blood glucose, serum Adrenocorticotropic Hormone (ACTH), insulin and glucagon concentration. Methods 21 to 22, healthy, 28 male university students participated in the study. They were randomly divided into a control group (n=16)and an experimental group(n=12). All participants completed four-stage incremental load movement for a total of 32 days. The exercise intensity of four stages was 60% VO2max, 70% VO2max, 80% VO2max and 90% VO2max, respectively. Each stage was exercised every-other-day, 4 times per stage and 1 hour each time. During the exercise, each subject in the experimental group drank 100 ml of 100% Lycium Barbarum juice before going to bed every day. Before the experiment and the morning after the end of each phase, a participant’s elbow-venous blood was collected to separate the serum. In all serum substances, the concentrations of ACTH, insulin, glucagon were detected by ELISA system. Fasting blood glucose concentration was detected by a blood glucose meter (Kyoto GT-1640 glucose meter, Japan). SPSS 17.0 software was used for statistical analysis. Results 1) The serum ACTH concentration of the subjects continually increased with the progress of the incremental load exercise and reached the highest at the end of the fourth stage. Compared with the increase in the control group (P<0.05), the experimental group was more significant (P<0.01). 2) Compared with before the experiment, both control group and experimental group were no obvious changes of blood glucose concentration in the first and second stages, and the control group was significantly decreased in the third and fourth stages (P<0.05), while the experimental group was not (P>0.05). 3) During the increasing load exercise, the changes of insulin in serum of the participants were basically the same. The insulin level increased significantly at the end of the first stage and decreased successively at the end of the last three stages. At the end of the fourth stage, the serum insulin level of the control group decreased more significantly (P<0.05) than the experimental group (P>0.05). 4) The glucagon concentration in the control group continued to increase with the increase of the load. By contrast, the glucagon concentration in the experimental group gradually decreased at the end of the first stage and then increased at the end of the fourth stage. However, all of the increase and decrease are not statistically significant. Conclusions During increasing resistance exercise, drinking Lycium Barbarum juice can increase the ability of the body to regulate Adrenocorticotropic Hormone (ACTH), insulin and glucagon through the exercise stress regulation systems, the Hypothalamic-Pituitary-Adrenal Cortical Hormone system (HPA) and the Sympathetic-Adrenal Medullary system. It plays an important role in maintaining blood sugar levels during increasing resistance exercise and accelerating post-exercise function recovery after exercise

OR-023 Physical evaluation of 6-7 years old female preselected tennis players

Objective Through testing and analysis the characteristics of body shape，body composition，bone growth and physical fitness，hemoglobin, testosterone of 6-7 years old female preselected tennis players，the study aim was to provide reference bases for the early selection of female tennis players. Methods A total of 75 female preselected tennis players(initial selection by the coaches) aged from 6 to 7 years were came from Hebei, Hubei, Qinghai and Inner Mongolia province, who came to Research Center for Heath related Physical Fitness Evaluation of Guangzhou Sport University for physical fitness test from July 2016 to July 2018. The height, weight, length of upper limbs, length of lower limbs, iliac width, shoulder width, body fat, muscle mass, bone age，bone mass density(BMD), anaerobic power and PWC170, reaction time, vertical jump, grip strength, hemoglobin, testosterone were measured using related instruments and methods, and calculated derived indicators BMI, iliac width/shoulder width. Data were compared with the national standard of physical health of students and/or evaluated by deviation method，and correlation had been analysed among physical parameters. Results 1)The 75 female preselected tennis players’ aged from 6 to 7 years height and weight were 128.10±5.32cm and 25.70±3.87kg，and there are 47 girls height upper medium grade level, 60% of which weight was at a moderate level, their BMI were 15.48±1.50kg/m2，and all in the normal range, iliac width/shoulder width ×100 was 76.52±7.00, 70.7% 0f which was above medium grade level, the upper and lower limbs were 54.28±3.60cm and 71.68±5.26cm, girls’ PBF were 21.03±6.44, muscle weight were 18.94±3.00kg, BMD were 2.04±2.20, and no low bone strength were fund; Anaerobic power of all female preselected tennis players were 135.93±31.65kg.cm, and the values of the PWC170 relative weight were 10.79±2.56kg.m/min.kg, reaction time were 0.628±0.128s, vertical jump were 21.13±4.95cm, the grip of right and left hand were 10.36±2.15kg and 10.06±2.40kg, the physical fitness parameters above in the upper middle class were more girls than the lower middle class; The hemoglobin content was 132.15±8.70g/L, which was above the normal level (110 -160g/L), the serum testosterone concentration was 1.52±1.20umol/L, which was much higher than that of normal girls (0-0.7umol/L). 2) When age was controlled, there was negative correlation between T and PFB, vertical jump and body weight, PWC170 and reaction time(P＜0.05), and there was positive correlation between hemoglobin and muscle weight(P＜0.05), height, and vertical jump(P＜0.01), muscle weight and anaerobic power(P<0.01)，anaerobic power and height，weight，BMI，upper and lower limbs(P<0.01, P<0.01, P<0.01, P<0.05, P<0.01)，PWC170 and vertical jump，the grip of right and left hand(P<0.01, P<0.05, P<0.05), vertical jump and upper, lower limbs, iliac width/shoulder width(P<0.01, P<0.01, P<0.01). Conclusions 75 female aged from 6 to 7 years old preselected tennis players’ body shape, physical fitness, physiological and biochemical function were superior to peers, and in those parameters，there were more people in upper middle grade than  lower middle grade. There is a certain correlation between body composition, shape and fitness of female preselected tennis players’ aged from 6 to 7 years

PO-071 Effects of Resistance Training of Different Loads on Gastrocnemius Protein, IGF-I and TNF-α in Aging Rats

Objective To observe the effects of different load resistance training on skeletal muscle dystrophy in aging rats by observing the expression of protein and protein of IGF-I and TNF-α in aging rats after 8 weeks of different load resistance training. The resistance training delays the theoretical basis for anti-skeletal muscle aging. Methods 40 aging SD rats (18 months old) were randomly divided into a quiet control group, a non-weight-bearing exercise group, 30% of the largest negative recombination, 50% of the largest negative recombination, and 70% of the largest negative recombination. The sports group carried the treadmill movement with the tail load, the slope was 35°, the running speed was 15m/min, the rest was 30s every 15s, the rest was 3min after four cycles, and the three groups were one cycle. The cycle was intermittent for 10 minutes, and the exercise frequency was the next day for 8 weeks. After 8 weeks, the rat gastrocnemius muscle was taken. The protein content of the gastrocnemius muscle was determined by Coomassie brilliant blue method. The contents of IGF-I and TNF-α in the gastrocnemius muscle were determined by enzyme-linked immunosorbent assay. Results After 1.8 weeks of different load resistance exercise, compared with the quiet control group, the skeletal muscle protein content of each exercise group increased, among which 50% of the largest negative recombination and 70% of the largest negative recombination was the most significant (P<0.01). Compared with 70% of the largest negative recombination, the 50% maximum negative recombination content was relatively high (P<0.05); After 8 weeks of different load resistance exercise, compared with the quiet control group, the content of IGF-I in the gastrocnemius of each exercise group was higher than that of the quiet control group, and there was a very significant difference (P<0.01), and 50%. The highest negative recombination and 70% of the largest negative recombination content is the highest; After 8 weeks of different load resistance exercise, compared with the quiet control group, the TNF-α content in the gastrocnemius muscle of the rats in each resistance exercise group increased slightly, and the increase of only 50% of the largest negative recombination was statistically significant (P<0.05), although there were differences between the exercise groups, there was no statistical significance (P>0.05). Conclusions 50% of the maximum weight-bearing resistance training can effectively increase the skeletal muscle muscle protein content of aging SD rats, and it is related to up-regulation of IGF-I factor and down-regulation of TNF-α factor expression by resistance training

PO-179 Prevention of sarcopenia and regulation of the ERK1/2 and p38MAPK phosphorylation by resistance training

Objective Study of the effect of treadmill resistance training on the cross section and phosphorylation of ERK1/2 and p38MAPK of gastrocnemius of aging rats, and explore the role of resistance training in prevention and regulation of sarcopenia. Methods 11-month-old male Sprague-Dawley (SD) rats (n = 40, SPF grade, initial body weight 776.9 ± 50) were raised in various cages in a room with a room temperature of 23 ± 2°C, a humidity of 40–60%, and a natural light/dark cycle. After eight months, the treated rats were then divided into one sedentary group (control, n = 8/group) and four groups for resistance training (GRT 1-GRT 4, GRT for Group for Resistance Training, n = 8/group) lasting for 8 weeks. For resistance training, GRT1 to GRT4 carried no loading, 30% maximum loading, 50% maximum loading and 70% maximum loading, respectively. The protocol for treadmill running was as follows: 15m/min (speed), 35°C (slope), 15s each time, an interval for 30s between two runnings, four runnings as one training, an interval for 3mins between two training, three training as one cycle, two cycles one training day, and one-day break between two training days. The morphology and cross section of gastrocnemius and the phosphorylation of the ERK1/2、p38MAPK proteins in the rats were examined after 8 weeks’ training.  Results Compared with the control, GRT1-GRT4 displayed relatively better aligned muscles fibers and noticeably larger cross-sectional area (P＜0.05). The content of p-ERK1/2 (phosphorylated ERK1/2) displayed a descending trend as the loading increased compared with the control (GRT1 VS control, P＞0.05; GRT2 VS control, P＜0.05; GRT3 VS control, P＞0.05; GRT4 VS control, P＞0.05). However, the pairwise comparison revealed that only the difference between GRT1 and GRT2 was significant. Similarly, the content of p-p38MAPK (phosphorylated p38MAPK) displayed a descending trend as the loading increased compared with the control (GRT1 VS control, P＞0.05; GRT2 VS control, P＞0.05; GRT3 VS control, P＜0.01; GRT4 VS control, P＜0.01). Besides, the pairwise comparison revealed that the difference between GRT1 and GRT3 was significant (P＜0.05) and that between GRT1 and GRT4 was even highly significant (P＜0.01). Conclusions Resistance training with middle-class intensity or above can prevent sarcopenia. ERK1/2 and p38MAPK were subject to high-level phosphorylation in aging skeletal muscles, which resulted from the stress-like status of the aging body. Treadmill training of with middle-class intensity or above can reduce ERK1/2 and p38MAPK phosphorylation in aging skeletal muscles of rats, which indicates that resistance training can effectively prevent sarcopenia by inhibiting ERK1/2 and p38MAPK phosphorylation

OR-015 The changes of p-Akt/MuRF1 proteins expressions in rats’ soleus muscle following three preconditioning exercise under simulated acute microgravity

Objective To observe the effect of three training ways, aerobic training, resistance training and aerobic combined with resistance training on cross-section and p-Akt/MuRF1 proteins expressions in rats’ soleus under simulated acute microgravity, the purpose of this study was to explore its roles in preconditioning exercise and the appropriate training methods to prevent the muscle atrophy in acute microgravity. Methods 32 male SD rats (aged 6 wk) were randomly distributed into four groups: control group (CON, n=8), aerobic training group (AER, n=8), resistance training group (RES, n=8) and aerobic combined resistance training group (ACR, n=8). The training groups were trained once every other day, while CON was not trained. Rats in AER trained on an animal treadmill with the 0° at the speed of 35 m/min for 45 minutes. The rats in AER were trained by running resistance method, loaded with 50% of its weight in the tail of the rat, each training section included 4-repetition of 15-second 35° climbing on treadmill at the speed of 15 m/min, with the interval of 30 seconds between repetitions，and 3 minutes between sections, each circle comprised 3 sections, and 2 circles at a time. The rats of ACR were requested to carry out an aerobic training(25min) and a resistance training(1 circles) in training day. After 6 wk training, all rats were under the simulated acute microgravity (hindlimb suspension), the 6th-day soleus muscles were excised and muscle cells cross-section area(CSA) were observed, and p-Akt/MuRF1 proteins expressions were analyzed by Western blot. Results 1) After 5 days of acute microgravity stimulation, the CSA of soleus muscles of rats in the three training groups were larger than those in CON, and RES and ACR have statistical significance (P<0.05, P<0.01). In three training models, ACR was significantly greater than the aerobic training group and resistance training group (P<0.05), and RES was significantly greater than AER (P<0.05).  2) Compared with CON, the p-Akt protein expression in the soleus muscle of rats in AER was significantly decreased (P<0.01), while it was increased in both RES and ACR, and in ACR increased significantly (P<0.01). Among the three training methods, the p-Akt proteins expressions in the soleus muscle of rats in ACR was significantly higher than AER (P<0.01)and RES (P<0.05).  3) Compared with CON, the MuRF1 proteins expressions in soleus muscle of rats in ACR are not significantly change (P>0.05), while AER and RES increased significantly (P<0.01, P<0.05). At the same time, the MuRF1 proteins expressions in soleus muscle of rats in AER and RES is significantly higher than ACR (P<0.01), and AER is significantly higher than that RES (P<0.01). Conclusions Three training models have certain effects on preventing muscle atrophy in the acute microgravity environment, and the effect of aerobic combined resistance training is the best, which may relate to up-regulating the p-Akt proteins expressions in skeletal muscle and inhibiting the MuRF1 proteins expressions in the acute microgravity environment

PO-067 Effects of oral Lycium barbarum juice in red blood cell antioxidant biomarkers and physical function during 8 days of aerobic exercise

Objective Lycium barbarum polysaccharide (LBP) is the main active components of Lycium barbarum, its benefits to anti-aging, vision, kidney, and liver functions. Nevertheless, there is still a scarcity of experimental evidence to support the effect of Lycium barbarum on aerobic exercise.This a randomized controlled trial was observed the effects of oral Lycium barbarum juice in red blood cell antioxidant biomarkers and physical function during 8 days of aerobic exercise. Methods 28 healthy male college students were divided into control group（16）and experimental group（12），and underwent interval running once every other day，total of 8 days. Exercise program: An exercise session includes two 30-minute aerobic exercises at 60%VO2max and a five-minute break. For the duration of the 8 days period, participants exercised one time every other day and the experimental group drank 100ml Lycium barbarum juice (each LBP content 360-440mg%) at bedtime every night. In ninth days, all the experimenters did exhaustive exercise with 80%VO2max on a treadmill with 8°.simultaneous recording of motion duration. The levels of red blood cell SOD, MDA, GSH-PX, serum CAT, serum TAC and other oxygenation stress markers and BLA, Glu, Urea, CK, Urine eight items and other physical function indexes of the subjects were determined before the experiment and after the completion of each intensity exercise. Differences between before and after intervention values were tested using a paired t test.And to compare the mean of outcomes in quantitative variables between the 2 groups, a independent t-test was used. The SPSS software (version 17, SPSS Inc, Chicago, IL, USA) was applied for data analysis and statistical significance was accepted at P < 0.05. Results (1)After 8 days of oral Lycium barbarum juice, the exhaustion time of exercise force in the experimental group was 30.76 ±12.19min, while the control group was 23.64±8.56min. Compared with the control group, the average exercise exhaustion time of the experimental group was prolonged 7.12min. (2)The red blood cell SOD in the two groups after 8 days of aerobic exercise had significant and significant improvement (P < 0.05, P < 0.01), and moreover, the increase of the experimental group was significantly higher than that of the control group (P < 0.05).As well as, the blood erythrocyte GSH-PX and serum TAC were significantly enhanced after the experiment (P < 0.01).It is suggested that increasing the levels of SOD and GSH-PX in vivo is beneficial in scavenging the free radicals produced by body movement. (3)After the 8 days oral Lycium barbarum juice, the decrease of MDA in blood red blood cells in the experimental group was greater than that of the control group (P < 0.01), indicating that the juice of Lycium barbarum could reduce the production of lipid peroxide products. (4) Exhaustion exercise after 8 days of oral Lycium barbarum juice, the physical function indexes of the experimental group, such as BLA, Urea, and CK were reduced. The positive rate of eight urine items was less than that in the control group, 8 in the control group, 2 for bilirubin positive, 3 in the urinary occult blood and 5 in the urine protein, while only 1 in the experimental group were positive for urine protein.   Conclusions Oral Lycium barbarum juice can improve the activity of antioxidant enzymes during aerobic exercise, reduce the formation of lipid peroxides in the body, protect the biological function of red blood cells, improve the physical function and postpone the production of sports fatigue

PO-165 Effects of Living-High Training-Low on HIF-1α Transcriptional Regulatory Factors MAPKs mRNA in Gastrocnemius of Rats

Objective To evaluate the effects of Living-High Training-Low on HIF-1α transcriptional regulatory factors MAPKs mRNA in gastrocnemius of Rats. Methods After adaptive training, 40 8-weeks-old male SD rats were divided into living-low quiet control group (LC), living-low training-low group (LoLo), living-high quiet control group (HC), living-high training-low group (HiLo). All living-high groups stayed in the environment with 13.6% oxygen concentration, about altitude of 3500 m, for 12h/day. All training groups underwent treadmill training with 35m/min for 1hour/day, 5days/week. 4 weeks later, the gastrocnemius was sampled 24 hours after the last training. The ERK, p38MAPK, JNK and HIF-1α mRNA genes expressions in gastrocnemius were measured by real-time quantitative PCR. Results The gastrocnemius ERK mRNA of HiLo group was significantly higher than LC (P<0.01), LoLo and HC groups (P<0.05). The p38MAPK mRNA of HiLo group was significantly higher than LC and LoLo groups (P<0.01 and P<0.05), and there was no significant difference between HiLo and HC group (P>0.05). The JNK and HIF-1α mRNA of HiLo group were significantly higher than other groups (P<0.01). Conclusions Living-High Training-Low significantly raise ERK、p38MAPK、JNK and HIF-1α gene expression in gastrocnemius of Rats. ERK, p38MAPK and JNK may be one of the transcription factors regulating HIF-1α mRNA expression in Living-High Training-Low in gastrocnemius of Rats

OR-007 Identification of Early Predictive Biomarkers for Exercise-induced Immunodepression by Urinary iTRAQ-proteomic Analysis

Objective Exercise-induced immunodepression is a common medical problem in competitive sports, leading to upper respiratory tract infection, affecting sports training and sports performance, and increasing athletes' sports disease and injury risk. Finding non-invasive early predictive biomarkers of exercise-induced immunodepression and giving corresponding preventive measures is therefore an important issue in sports training. iTRAQ is an important method that currently looking for and discovering disease-specific protein biomarkers of disease prevention, diagnosis, prognosis, and efficacy monitoring. In this study, early predictive biomarkers of exercise-induced immunodepression will be identified through the iTRAQ proteomics technique, which helps to prevent the occurrence of exercise-induced immunodepression. Methods Fifteen healthy males were recruited from the student cohort of Guangzhou Sport University. Subjects performed four-week incremental load running exercise. The weekly running load intensity was 60% VO2max, 70% VO2max, 80% VO2max, 90% VO2max respectively, 5d/w, and 1h/d. The fasting venous blood and urine of the subjects was collected in the morning before the start of the training intervention and at the end of each training week. The white blood cells of the whole blood and the levels of the lymphocyte subtypes CD4+ and CD8+ were tested to monitor the immune function status of the subjects. iTRAQ proteomics technology was used to test and identify differential proteins and their characteristics in urine. Results During the four weeks of increasing running load, the subject’s immune function was progressively reduced. Whole blood white blood cells, and CD4+ and CD8+ lymphocyte fell by more than 10% at the end of the fourth week, showing exercise-induced Immunodepression. Using iTRAQ to test urine proteomes, there were as many as 1854 proteins in the urine during the incremental loading process. The relative molecular weights of most of the proteins were between 10-80 kDa, and the isoelectric point was between 4.5 and 7. During the four weeks of incremental loading running, there were 89, 52, 77, and 148 differential proteins up-regulated, and 66, 27, 68, and 114 differential proteins downregulated respectively in the urine of each week. The differential proteins were mostly found in extracellular and plasma membranes. It is mainly involved in the in vivo biological process, the immune system process, the material transport, and is related to the positive regulatory pathways and immune regulatory pathways for stress response. The up-regulation multiples of four up-regulated proteins such as Semenogelin-1, Prolactin-inducible protein, Platelet-derived growth factor receptor-like protein, and Nucleoside diphosphate kinase increased with increasing exercise intensity. The up-regulated multiples of Glycerol-3-phosphate phosphatase, Secretogranin-1, Prosaposin, and Nephronectin (Fragment) increased with increasing exercise intensity from the second week of exercise. The down-regulation multiples of Ig kappa chain C region, Immunoglobulin lambda variable 3-21 of CUB and EGF-like domain-containing protein 2 and Uromodulin decreased further with the increase of exercise intensity from the second week of exercise, which was consistent with the change of immune function. Conclusions Urine iTRAQ proteomics technique is an important method to identify early predictive biomarkers of exercise-induced immunodepression, which helps to prevent the occurrence of exercise-induced immunodepression. In this study, the differential proteins in urine, such as Semenogelin-1, Prolactin-inducible protein, Platelet-derived growth factor receptor-like protein, and Nucleoside diphosphate kinase can be considered as early predictive biomarkers of exercise-induced immunodepression

Intermittent Hypoxia Exposure Helps to Restore the Reduced Hemoglobin Concentration During Intense Exercise Training in Trained Swimmers

In prolonged intense exercise training, the training load of athletes may be reduced once their hemoglobin concentrations ([Hb]s) are decreased dramatically. We previously reported that intermittent hypoxia exposure (IHE) could be used to alleviate the decrease of [Hb] and help to maintain the training load in rats. To further explore the feasibility of applying IHE intervention to athletes during prolonged intense exercise training, 6 trained swimmers were recruited to conduct a 4-week IHE intervention at the intervals after their [Hb] dropped for 10% or more during their training season. IHE intervention lasted 1 h and took place once a day and five times a week. Hematological and hormonal parameters, including [Hb], red blood cells (RBC), hematocrit (Hct), reticulocytes, serum erythropoietin (EPO), testosterone (T) and cortisol (C) were examined. After the IHE intervention was launched, [Hb], RBC and Hct of the subjects were increased progressively with their maximum levels (P < 0.01) showing at the third or fourth week, respectively. An increase in reticulocyte count (P < 0.01) suggests that IHE intervention promotes erythropoiesis to increase [Hb]. Besides, serum level of EPO, the hormone known to stimulate erythropoiesis, was overall higher than that before the IHE intervention, although it was statistically insignificant. Furthermore, the serum level of T, another hormone known to stimulate erythropoiesis, was increased progressively with the maximum level showing at the fourth week. Collectively, this study further confirms that IHE intervention may be used as a new strategy to prevent intense exercise training-induced reductions in [Hb]