高压氧对高原移居青年体力作业效率的影响

目的探讨高压氧对高原移居青年体力作业效率的影响。方法将进驻海拔3 700 m半年的20名健康青年随机分为两组,每组10人。分别采用高压氧前(对照组)和高压氧2次(A组)及5次(B组)后第2天和第8天进行自身对比运动负荷实验。受试者用EGM型踏车功量计做坐位踏车运动。初始负荷功率50W,每3 min递增50W,以60 r/min连续踏车至200 W3 min后终止。用直线回归法计算每位受试者运动心率达170次/min时机体所做的功(PWC170)和运动功率90 W时的心率(HR90W),记录功率200W时的肺通气量及血氧饱和度(SaO2),计算心功能指数。结果两组高压氧组较对照组PWC170、SaO2及心功能指数均增高(P<0.01);HR90W、肺通气量降低(P<0.01),且其效率能保持1周。结论高压氧能明显提高高原移居青年的体力作业效率。     

进驻海拔3680m青年通气无氧阈的初步观察

目的 :观察进驻海拔 3 680m青年的通气无氧阈 ;方法 :受试者坐于踏车功量机上 ,以 60rpm连续蹬车 ,每 3分钟递增 2 5W ,蹬车至力竭时停止 ,用O2 CO2 气体测定仪分析每个负荷最后半分钟的O2 和CO2 ,用心电图机同步记录心率 ,计算肺通气量 ( ·VE)、氧耗量 ( ·VO2 )、二氧化碳产生量 ( ·VCO2 )、呼吸商 (RQ)及氧通气当量 ( ·VE/ ( ·VO2 ) ;结果 :·VE、·VO2 、·VCO2 在功率达 75W时出现明显增加 ;RQ在功率达 75W时出现“拐折点” ;·VE/ ·VO2 在功率达 75W时由下降转向平稳 ;结论 :进驻海拔 3 680m青年通气无氧代谢阈为功率 75W。     

富氧水对高原移居青年体力作业效率的影响

目的探讨富氧水对高原移居青年体力作业效率的影响。方法将进驻海拔3 700 m半年的20名健康青年随机分为AB两组,每组10人。A组口服富氧水2 d,2次/d,500 ml/次;B组口服富氧水5 d,2次/d,500 ml/次。分别在服富氧水前和服完富氧水后第2天和第8天进行运动负荷实验。受试者用EGM型踏车功量计做坐位踏车运动。初始负荷功率50 W,每3 min递增50 W,以60 r/min连续踏车至200 W 3 min后终止。用直线回归法计算每位受试者运动心率达170次/min时机体所作的功(PWC170)和运动功率90 W时的心率(HR90W),记录功率200 W时的肺通气量及血氧饱和度(SaO2),计算心功能指数。结果两组服富氧水后较服富氧水前PWC170、SaO2及心功能指数均增高(P<0.01);HR90W、肺通气量降低(P<0.01),且其效率能保持1周(P<0.05)。结论富氧水能明显提高高原移居青年的体力作业效率。     

高原红细胞增多症患者进入平原后心肺功能的变化

本文通过对9名高原红细胞增多症患者分别在西宁(2260米)和苏州(10米)进行了静息和运动状态下有关心肺功能参数自身对比观察。发现与在西宁相比,患者在苏州静息状态下每分通气量不降低,而心率减慢、氧耗量降低,氧当量增高;在相同负荷运动中通气量低,心率慢、氧耗量和代谢量单位等都低,而AT值(无氧代谢阈值)增高。提示高原红细胞增多症患者进入平原后运动耐力增加,心肺功能有所改善。     

定量负荷运动对人体胃肠激素浓度的影响

目的:探讨定量负荷运动对血液胃肠激素的影响。方法:9名体育学院健康男性大学生,进行哈佛台阶定量负荷运动,测定其运动前安静时及负荷Ⅰ、Ⅱ、Ⅲ后即刻心率和主观体力感觉等级,及其安静及定量负荷后即刻、10min、30min和60min血清胃泌素(GAS)、血浆胰高糖素(GLU)和血管活性肠肽(VIP)水平的变化。结果:本实验采用的运动负荷介于近极量强度与亚极量强度之间,运动后产生明显的疲劳症状。定量负荷运动后10min,血清GAS浓度较安静时显著升高(P<0·05),运动后60min基本恢复至安静水平;运动后30min血浆GLU浓度较安静时显著升高(P<0·05),运动后60min仍未恢复到安静水平;定量负荷后即刻血浆VIP浓度较安静时明显升高,运动后60min仍处于较高水平,但运动后各时点值与安静值比较均无统计学意义。上述结果提示定量负荷运动对血液胃肠激素含量有一定的影响。     

11～16岁肥胖青少年体力活动耗氧量推算方法实验研究

目的:采用多水平线性模型分析方法建立适用于肥胖青少年的耗氧量推算方程,为测量体力活动能量消耗提供简便有效的方法。方法:以60名11~16岁年龄段的肥胖青少年为研究对象,随机分为公式组(40名)和回代验证组(20名),男女各半。公式组在坡度为0的跑台上以2km/h、3km/h、4km/h、5km/h、6km/h、7km/h、8km/h的速度运动,每级负荷持续2.5分钟后继续增加,以心率达到80%HRmax为运动终止标准。采用气体代谢系统连续测量运动过程中耗氧量和心率,建立耗氧量多元线性回归方程,并进行回代验证。结果:所建回归方程R2男生为0.795,女生为0.75;耗氧量与负荷心率、瘦体重(LBM)具有线性关系(P<0.001);自变量系数及常数项均有极显著意义,得回归方程为男:耗氧量(ml/min)=20.098×负荷心率(bmp)+25.160×瘦体重(kg)-2935.835;女:耗氧量(ml/min)=19.863×负荷心率(bmp)+26.551×瘦体重(kg)-2675.676。回代验证组耗氧量预测值与实测值的平均相对误差男生为6.84%～8.72%,女生为6.53%～8.23%。结论:以负荷心率和瘦体重为自变量建立耗氧量的多元回归方程,可应用于肥胖青少年体力活动耗氧量的推算。     

高原体力活动时心率与耗氧量、能量代谢率的关系——高原体力劳动强度及其卫生限度探讨

本文报告海拔3 450米地区体力活动时心率与耗氧量、心率与能量代谢率之问的试验结果,表明两者之间存在相关,其回归方程式为:Y=-2.2754+0.04117x+0.0001117x~2 R~2=0.9960Y=-5.5812+0.091577x+0.0002024x~2 R~2=0.9971并且在同样负荷强度时,心率随海拨增高而增加。作者建议高原地区不同海拔劳动强度应有不同等级划分,海拔3 450米地区体力活动以心率150次/分、耗氧量1.37升/分、能量代谢率3.66千卡/分·平方米作为卫生限度。     

热环境下越野锻炼增强抗疲劳能力的研究

16名青年男子,分为锻炼组和对照组(每组8人)。锻炼组于热宝(34.5℃)平板机上按循序渐进原则进行模拟5km越野锻炼,二周内共10次(天),前3次徒手,后7次武装,于锻炼期前后两组分别进行高温、常温踏车力竭和五项体力运动作为引致疲劳的标准体力负荷,以评定锻炼对耐热力、体力和疲劳的影响。结果发现:锻炼后锻炼组高温踏车力竭功量较锻炼前显著增加,全血乳酸含量下降,直肠温度和心率明显降低,出汗量增加20%,心每搏量和每分量、肺通气量和氧耗量、血清睾酮和尿香草扁桃酸都呈适应性改善,疲劳症状和PPE大大降低。对照组各项指标的变化均无统计学意义。本实验表明,高温越野锻炼对增强耐热力、体力和延缓疲劳具有明显的效果。     

不同吸入气氧浓度对运动负荷肺通气量和心率动态反应的影响

10名健康男性青年在自行车功量计上进行125W 运动负荷试验,观察肺通气量((?)E)和心率(HR)动态反应。实验分三组:低氧组,吸入14%O_2—N_2混合气;常氧组,呼吸室内新鲜空气;高氧组,吸入60%O_2-N_2混合气。用二阶指数方程来拟合运动期(?)E 和HR 动态反应,取得了满意结果。(?)E 和HR 都可模式地划分为快、慢两种成分,两种成份值的大小和反应速度对评价呼吸和循环功能有一定意义。HR 反应快,达到稳态时间短,但恢复期长,在低氧条件下恢复更慢,心率可作为运动恢复的客观指标。     

热习服对中长跑运动员湿热环境下运动体液调节激素及Hsp70的影响

目的:探讨热习服对湿热环境下运动机体体液调节激素ALD、AVP、ANP、NE及Hsp70的影响。方法:16名中长跑运动员随机分为热习服组(HA)和对照组(HC),每组各8人;HA组先进行10天的热习服方案,使机体产生热习服,然后进行一次33℃、80%RH湿热环境下的40min、70%VO2max运动强度的热负荷运动;HC组不经过热习服阶段,直接进行一次同于热习服组的热负荷运动。热负荷运动前后测试实验对象的热应激的生理学指标及体液调节激素ALD、AVP、ANP、NE及Hsp70的水平,观察两组实验对象测试指标在热负荷运动前后的变化。结果:热负荷运动后,HA组和HC组核心温度和心率均非常显著性升高(P<0.01),出汗率无显著变化;HA组热负荷运动后的核心温度和心率水平比对照组低、出汗率水平比对照组高,但两组间差异无统计学意义。与运动前相比,HA组和HC组热负荷运动后红细胞压积非常显著性升高(P<0.01)。与运动前相比,HA组和HC组运动后ALD和NE非常显著性升高(P<0.01),AVP显著性升高(P<0.05),ANP显著性降低(P<0.05),Hsp70非常显著性升高(P<0.01),但组间检验均未见显著性差异(P>0.05)。结论:体液调节激素对维护热负荷运动过程中的机体水盐代谢和平衡发挥着重要作用;热习服一定程度上降低了机体对热负荷运动应激的生理生化热调节反应,提高了机体适应运动热环境的能力。     

Deconditioning-induced exercise responses as influenced by heat acclimation.

Five young men were tested on a bicycle ergometer before (Test 1) and after (Test 2) 8 d of heat acclimation (exercise at 50% of Vo2max at 39.8 degrees C DB, 30.0 degrees C WB) and after 8 h of water immersion (Test 3). A control group of five subjects underwent a similar procedure in a temperate environment of 23.8 degrees C. Heat acclimation resulted in the usual decreases in exercise heart rate (30 beats/min) and rectal temperature (0.6 degrees C) and an increase in sweat rate (19%). The control group showed effects of moderate training by decreases in exercise heart rate (11 beats/min), rectal temperature (0.3 degrees C), and sweat rate (24%). Water immersion resulted in substantial diuresis in both groups, despite 1800 ml of water consumed by each subject. In the acclimation group, exercise responses in Test 2 were better than in Test 1, with little improvement shown by the control group. The acclimation group maintained exercise responses in Test 3 as in Test 1, with more adverse responses shown by the control group. The results show that heat acclimation provides an effective method to prevent the adverse effects of water-immersion deconditioning on exercise tolerance.     

A comparison of the perceived and the ECG measured heart rate during cycle ergometer, treadmill and stairmill exercise before and after perceived heart rate training.

The ability to perceive exercise heart rate before and after training was tested in six young male university students, perceptions of heart rate being compared with ECG monitored heart rates during cycle ergometry, treadmill running and stairmill climbing. Between initial and final tests, subjects undertook 13 weeks of running training (2 h/day, 3-4 days/week), and during this period they compared their perceptions of heart rate with values observed on watch-type wrist-mounted pulse monitors. Individual initial perceptions showed only a moderate correlation with ECG values. This correspondence was improved as perceptions were compared with measured heart rates over the course of training, significantly so for the mode of exercise most similar to that adopted in the training sessions (treadmill running at a heart rate of 140 beats/min). The final accuracy of perceptions at a heart rate of 140 beats/min (error 8-9 beats/min during treadmill running) compared favourably with the accuracy of either pulse counting or the traditional rating of perceived exertion as commonly observed in the exercising public. This suggests that there may be an application for perceived heart rates in regulating the intensity of prescribed exercise.     

Effects of steady state exercise on the power spectrum of heart rate variability

The effects of steady state exercise on the power spectrum of heart rate variability were studied in 19 healthy subjects. Continuous ECG signals were recorded during 1) 15 min of rest in the supine state, 2) 10 min of standing, 3) 10 min of steady state exercise at 50% of maximum predicted power output on a cycle ergometer, and 4) 15 min of post-exercise recovery in the supine state. Autoregressive modeling was used to determine the power spectrum of heart rate variability. While orthostatic stress produced a significant 51% increase in the ratio of low to high frequency peak spectral power, steady state exercise caused a significant suppression of both low and high frequency components. The low frequency peak power rose to significantly high levels throughout 15 min of the post-exercise recovery period. There was a significant leftward shift in the frequency of the low frequency peak with exercise and a rightward shift during the recovery supine state. These results suggest that neuroregulatory control of heart rate plays a major role in adaptive responses to orthostatic stress and post-exercise recovery, while humoral factors are probably more important in maintaining heart rate during steady state exercise.     

Responses of distance runners and sprinters to exercise in a hot environment

The responses of highly trained distance runners and track sprinters and age-matched untrained men were compared during bicycle ergometry in a 40 degree temperature-controlled environmental chamber. There were no differences among groups in rectal temperature following the 90 min exercise bout. Distance runners had a lower heart rate than either sprinters or untrained subjects. There was no difference in heart rate between sprinters and untrained subjects. Distance runners and sprinters had a much greater sweat rate than untrained subjects and dissipated a greater proportion of their total heat load by evaporation of sweat. Sprinters, however, had a lower sweat rate than distance runners in the hot environment and could only maintain as low a skin temperature as distance runners for 75 min of the 90 min session. Both aerobic training and anaerobic training confer some degree of protection from heat injury during exercise in a hot environment. However, sprinters have a higher heart rate and cannot sustain a low skin temperature as long as distance runners. Sprinters lost their advantage over untrained subjects in skin temperature after 75 min of exercise in a hot environment and did not have a lower heart rate than untrained subjects. Distance runners had a significantly lower heart rate and maintained a lower skin temperature than untrained subjects for the entire 90 min exercise bout.     

补充巧克力对长时间中等度运动休闲跑步后恢复的影响

目的：研究运动前补充巧克力对运动引起的生理和代谢变化及恢复的影响。方法：１２名１８～２０岁男性休闲跑步自愿者作为受试实验对象,采用交叉设计,每名受试者参加两次试验,在跑步机上跑步１小时,运动中心率保持在１４８～１５０次／分。结果：运动前补充５６ｇ巧克力１５分钟后,血糖水平显著升高（５．４２±０．８３ｍｍｏｌ／Ｌ）并且在运动结束及其后的３０分钟仍保持在相当高的水平（４．９２±０．５７ｍｍｏｌ／Ｌ）,而补充安慰剂的对照组在运动后血糖水平低（３．９７±０．３７ｍｍｏｌ／Ｌ）,停止运动３０分钟后血糖低于正常水平（３．８４±０．３１ｍｍｏｌ／Ｌ）。血浆自由脂肪酸、血乳酸、血浆尿素氮水平以及自我感觉疲劳程度（ＲＰＥ）等结果均表明运动前补充巧克力提供运动和运动后恢复所必要的条件均有益。     

Cardiovascular responses of pregnant women during aerobic exercise in water: a longitudinal study

To determine the effects of pregnancy on the cardiovascular responses to immersion and exercise in water, 12 women completed 20 min of immersion and 20 min of bicycle ergometry at 60% predicted VO2max in 30 degrees C water during their 15th, 25th, and 35th week of pregnancy as well as 8-10 weeks post partum. Immersion lowered the resting heart rate approximately 8 bts/min (P less than 0.05). Exercise in water also resulted in a lower heart rate as compared with the same level of exercise on land (132 +/- 4 vs 149 +/- 6 bts/min; P less than 0.05). Both the rest and exercise heart rate responses were independent of duration of pregnancy or pregnancy status. Post partum exercise cardiac output averaged 9.9 +/- 0.4 l/min, significantly lower (P less than 0.05) than the 15th (12.7 +/- 0.5), 25th (14.7 +/- 0.5), or 35th week (15.1 +/- 0.7 l/min). Total peripheral resistance was greatest (P less than 0.05) post partum (657 +/- 29 dyn.s/cm5) compared with either the 15th (515 +/- 27), 25th (407 +/- 18), or 35th week (450 +/- 23). The results indicate that exercise in water lowers the heart rate compared with land exercise at the same metabolic rate. The combined effect of exercise, water, and pregnancy may elevate the cardiac output more than expected on land, but the same general pattern of exercise response will be evident throughout the duration of pregnancy. The results further suggest that water alters the heart rate and blood pressure responses such that land-derived exercise target heart rates should not be used to prescribe exercise intensity in water.     

Effets d'un réentraı̂nement à l'effort réalisé au seuil ventilatoire chez l'insuffisant cardiaque

Objectives – Study was to assess the effects of exercise training at the ventilatory threshold on exercise tolerance and quality of life in subjects with chronic heart failure.Methods and results – Nine subjects with moderate chronic heart failureperformed: a maximal exercise test and a six-minute walk test and responded to a quality of life questionnaire, both before and after the training program. The exercise training consisted of 46 minutes of cycling, three times per week, for eight weeks, and the exercise intensity was the heart rate at the ventilatory threshold ±5 beats/min. The results showed that exercise training at the ventilatory threshold improves exercise tolerance (maximal and submaximal) and quality of life in subjects with chronic heart failure. These training benefits were very satisfactory compared with other results in the literature.Conclusion – An individualized exercise intensity set at the ventilatory threshold ensures optimal benefits of exercise training in subjects with chronic heart failure.     

Physiological responses to aerobic exercise during pregnancy and post-partum

Maternal physiological responses to exercise during pregnancy and post-partum were studied. The results indicated that: (a) the maternal submaximal oxygen consumption (1/min) at a constant heart rate remained essentially unchanged during the last two trimesters of pregnancy and eight months post-partum, (b) the fetal heart rate returned to near-baseline levels within a two-minute exercise recovery, and (c) the infant birth data were all within the normal range. It would appear that moderate aerobic exercise during pregnancy may be done without apparent harm to either mother or baby, and could possibly benefit the mother by maintaining her aerobic fitness during pregnancy.     

Hormonal and metabolic responses to exercise in subject of high and low work capacities

Hormonal and metabolic responses to submaximal were studied in eight normal subjects. Four subjects had high maximal oxygen uptakes (455 +/- 0.49/min) and were classified as "fit" and four had low maximal oxygen uptakes (2.13 +/- 0.32 1/min) and were classified as "unfit". All subjects exercised for 20 minutes at 750 kpm/min on a cycle ergometer, which represented 35% and 85% of the maximal oxygen uptake for the fit and the unfit subjects respectively. The unfit subjects had a higher heart rate and CO2 output at the same oxygen uptake when compared with the fit group. There was a high blood lactate in the unfit subjects and also a greater rise in blood glucose, plasma cortisol and serum growth hormone during exercise in these subjects. Free fatty acids increased in the fit subjects, but not in the unfit and serum insulin was depressed in both groups. Thus, the cardiorespiratory fitness is an important determinant of the hormonal and metabolic response to submaximal exercise, which differed considerably when fit and unfit subjects exercised at identical absolute levels of power output. These differences have implications for the control of energy substrates used during exercise.