| Haze weather occurred increasingly in North China in recent years, which has seriously influenced the people's normal life. The hallmark was the elevation of atmospheric fine particulate matter (PM25) concentration, and the harm of atmospheric PM2.5 pollution to human body's health drew more and more attention. PM2.5 in high concentrations will not only led to the decline of lung function, but can also increase the incidence and mortality of respiratory disease and even influence the people engaged in outdoor physical exercises. For track and field athletes, since they must adhere to the principle of system training in order to form and improve competitive abilities during the training period, which was uninterrupted, even if bad weather, so they will encounter haze weather inevitably. If exposure to high concentrations of PM2.5 weather conditions in the long term, which will certainly affect the athletes' health condition and sport performance. This study used the methods of the literature material law, questionnaire survey method, experimental method and mathematical statistics, and selected sprinters from the track and field team of Shanxi University as the research objects. Through the analysis the change of lung function index before and after the training by exposure to atmospheric PM2.5 under different training load, which aimed to explore the short-term health effects of atmospheric fine particulate matter under different training load on athletes' lung function, and provide gist for athletes' reasonable system training during the heavy atmospheric pollution in North China and put forward relevant suggestions. This study showed:(1) The characteristic of the arrangement of small training cycle is six-day a week for sprinters from the track and field team of Shanxi University. There are three types arranged for small training cycle of the training load capatity structure during the research. The training load rhythm is consisted of three small training cycle, including one of the medium training load capatity, one of the low training load capatity and one of the large training load capatity, and the proportion of three training load capatity is equal. The arrangement rules are as following:small cycle of the large training load capatity is arranged for three weeks, including training in large load capatity for three times a week on Tuesday, Wednesday and Saturday, respectively; training in medium load capatity for twice a week on Monday and Friday, respectively; training in low load capatity for once a week on Thursday. The small cycle of the medium training load capatity is arranged for three weeks, including training in large load capatity for twice a week on Wednesday and Saturday, respectively; training in medium load capatity for three times a week on Monday, Tuesday and Friday, respectively; training in low load capatity for once a week on Thursday. The small cycle of the low training load capatity is arranged for three weeks, including training in large load capatity for once a week on Wednesday; training in medium load capatity for three times a week on Tuesday, Friday and Saturday, respectively; training in low load capatity for twice a week on Monday and Thursday, respectively.(2) According to the testing results of athletes'lung function, it demonstrates that there were not abnormal pulmonary ventilation function and small airway function for athletes when training in medium and low load, but there may be abnormal small airway function for athletes when training in high load. We can speculate that it may be resulted form excessive ventilation for athletes when training in high load. The day of daily PM2.5 average concentration was higher than the standard 75.00 ?g/m3 (high PM2.5 concentration group) performed in 2016 in China was 20 days, and that was both 17 days between 35.00?g/m3 and 75.00?g/m3 (medium PM2.5 concentration group) as well as below 35.00?g/m3 (low PM2.5 concentration group) during the testing of lung function. According to the comparison of athletes' lung function index when training in different load and exposuring to different PM2.5 concentrations, when training in high load for 18 days, athletes' indicators reflecting lagre airway characteristics as VC (vital capacity), ERV (expiratory reserve volume), FEV1.0% (the ratio of forced expiratory volume in one second and forced vital capacity), MMF (maximal mid-expiratory flow), and indicators reflecting small airway characteristics as PEF (peak expiratory) and FEF75 (flow speed of expired air by 75% of the forced vital capacity) of high PM2.5 concentration group were significantly lower than that of medium and low PM2.5 concentration groups (P<0.05, P <0.01), and indicator reflecting lagre airway characteristics as FEV1.0 (forced expiratory volume in one second) of high and medium groups were significantly lower than that of low group, but there were not significant differences for indicator reflecting lagre airway characteristics as FVC (forced vital capacity), and indicators reflecting small airway characteristics as FEF2.5 (flow speed of expired air by 75% of the forced vital capacity), FEF50 (flow speed of expired air by 50% of the forced vital capacity) and indicator bobth reflecting lagre and small airway characteristics as MVV (maximum voluntary ventilation) between three groups (P> 0.05). When training in medium load for 24 days, PEF (peak expiratory) and FEF50 (flow speed of expired air by 50% of the forced vital capacity) of high and medium groups were significantly lower than that of low group, and FEF50 (flow speed of expired air by 50% of the forced vital capacity) of high group was significantly lower than that of medium group, but there were not significant differences for VC (vital capacity), ERV (expiratory reserve volume), FVC (forced vital capacity), FEV1.0 (forced expiratory volume in one second), FEV1.0%(the ratio of forced expiratory volume in one second and forced vital capacity), MMF (maximal mid-expiratory flow), FEF2.5 (flow speed of expired air by 25% of the forced vital capacity), FEF75 (flow speed of expired air by 75% of the forced vital capacity) and MVV (maximum voluntary ventilation) (P> 0.05). When training in low load for 12 days, there were not significant differences for every index of lung function between three groups (P>0.05).(3) PM2.5 had short-term negative effects and delayed effects on athletes' lung function indicators reflecting both large and small airway characteristics under different training load, especially for the large airway characteristics under high training load, and the adverse effects may be more sensitive in exercising. It was statistically significant for VC (vital capacity), ERV (expiratory reserve volume), FEV1.0 (forced expiratory volume in one second), and MMF (maximal mid-expiratory flow) with a rise in the PM2.5 concentration of 10 ?g/m3 resulted in the change of 3.57%,3.88%,4.12% and 3.15%(P< 0.05) before exercising and 6.48%,4.13%,4.69% and 3.15%(P<0.05, P<0.01) after exercising under high training load. When training in medium load, it was statistically significant for ERV (expiratory reserve volume) before exercising, which resulted in the change of 0.47%(P<0.05) and it was statistically significant for PEF (peak expiratory) and FEF50 (flow speed of expired air by 50% of the forced vital capacity) after exercising with a rise in the PM2.5 concentration of 10 ?g/m3 resulted in the change of 4.48% and 2.53%(P<0.05). But when training in low load, there were not statistically significant for athletes' every lung function index before and after exercising. We can speculate that it may result in the reduction of athletes' large airway function when training in high load, as well as the reduction of athletes' small airway function when training in medium load, and there will be not significant influence for athletes' large and small airway function when training in low load with the rising of PM2.5 concentration.Based on the research conclusion, the author put forward five suggestions:choose environment and time bucket of outdoor sports training scientifically and reasonably; choose training activities in medium and low load consciously; stop outdoor sports training activities immediately during the heavy haze weather; check athletes' pulmonary functiontimely for training outside; design the health protection measures of air environment for training. |
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