基于心率变异性的新兵跳伞训练心理应激研究

目的 以心率变异性指标对跳伞训练新兵的心理应激水平进行客观评估并研究其变化特点.方法 参加跳伞训练的新兵20名,跳伞7次,其中第1次、第4次和第7次跳伞当天佩戴飞行员飞行生理参数记录检测仪动态记录跳伞过程中的心电信号,采用与记录检测仪配套的数据分析系统分析伞兵在驻地、机场、机上的短时程心率变异性.结果 新兵第4次和第7...     

空降兵新兵跳伞心理应激水平与心率变异性的相关性分析

目的探讨空降兵新兵跳伞心理应激状况与心率变异性的关系。方法参加跳伞训练的新兵30名,跳伞前进行SCL-90症状自评量表测评,并记录分析跳伞前安静状态下30min的心电信号,与跳伞后1个月平时状态下的测量结果进行对照分析。结果与平时比较,跳伞前SCL-90症状自评量表强迫、抑郁、焦虑、敌对、恐怖、精神病性等因子分及总分明显升高（P〈0.05或P〈0.01）。心率变异性指标SDNN变化率与自评量表因子＂焦虑＂、＂恐怖＂评分变化率呈负相关,RMSSD变化率与因子＂强迫＂、＂焦虑＂、＂精神病性＂评分变化率以及HFNU变化率与＂焦虑＂、＂精神病性＂评分变化率也都呈负相关,LFNU变化率与＂焦虑＂、＂精神病性＂评分变化率呈正相关。结论空降兵跳伞前心理应激水平与心率变异性密切相关,提示心率变异性指标对评估跳伞前心理应激水平具有重要价值。     

新老伞兵跳伞后血浆肾素-血管紧张素-醛固酮变化比较

目的：观察跳伞训练时空降兵新、老兵血浆肾素-血管紧张素-醛固酮系统的变化,比较新老兵对跳伞应激的适应能力。方法：选择空降兵新兵40人(新兵组)、老兵30人(老兵组),一起进行跳伞训练,并完成10次跳伞任务;采用放射免疫法测定跳伞前、后及休整10天后血浆肾素活性、血管紧张素Ⅱ及醛固酮水平;并同时记录心电图和血压变化。结果：跳伞后新、老兵血浆肾素活性、血管紧张素Ⅱ及醛固酮浓度均明显升高,新兵组血压、心率升高。休整10天后老兵组肾素活性、血管紧张素Ⅱ回落至跳伞前水平,醛固酮浓度明显降低;新兵组肾素活性、血管紧张素Ⅱ及醛固酮水平回落,但血管紧张素Ⅱ水平仍高于跳伞前水平,且明显高于老兵组。结论：跳伞训练中新兵较老兵处于更强烈的应激状态,严重的跳伞应激可通过一定的跳伞训练得以减轻。     

跳伞训练对空降兵血浆儿茶酚胺含量及甲状腺功能的影响

目的　动态观察跳伞训练对空降兵新、老兵血浆儿茶酚胺、肾上腺素、去甲肾上腺素水平的影响及新兵甲状腺功能变化,探讨空降兵对跳伞应激的适应能力。　方法　选择空降兵新兵40人(新兵组)、老兵30人(老兵组),一起进行跳伞训练,19 d内完成10次跳伞任务;采用荧光法测定跳伞前、跳伞后及休整10 d后血浆儿茶酚胺、肾上腺素及去甲肾上腺素水平;同时采用放射免疫法测定新兵组甲状腺功能(FT3、FT4、TSH、TgAb和TmAb)变化;同时记录心电图和血压情况。　结果　①跳伞后新、老兵血浆儿茶酚胺、肾上腺素及去甲肾上腺素水平均明显升高(P<0 05 或<0 01),尤以新兵组升高更为明显并伴有血压、心率升高(P<0 01),其心律失常发生率也增高。②休整10 d后老兵组各项指标基本恢复至跳伞前水平;新兵组儿茶酚胺、去甲肾上腺素仍明显高于跳伞前水平(P<0 01)。③新兵跳伞后血清FT3 和FT4 水平明显升高、TSH水平明显降低。休整15 d后,FT3、FT4水平明显回降,但仍高于跳伞前水平(P<0 01); TSH水平较跳伞后明显升高(P<0 01)。　结论　①跳伞训练对新、老兵均是一种强烈的应激源,新兵较老兵处于更强烈的应激状态。②血清甲状腺素水平的高低一定程度上可反映机体跳伞应激反应的强弱。     

空降兵跳伞训练致血浆肾素-血管紧张素-醛固酮的变化

目的　动态测定跳伞训练对空降兵新、老兵血浆肾素 血管紧张素 醛固酮系统的影响 ,观察空降兵跳伞时的应激水平。　方法　空降兵新兵 4 0人、老兵 30人 ,每人均完成 10次跳伞。采用放射免疫法测定跳伞前、后及休整 10d后血浆肾素活性、血管紧张素Ⅱ及醛固酮水平。结果　跳伞后新、老兵血浆肾素活性、血管紧张素Ⅱ及醛固酮浓度均明显升高 (P <0 0 5或0 0 1) ;休整 10d后老兵组肾素活性、血管紧张素Ⅱ回落至跳伞前水平 ,醛固酮浓度明显降低 (P <0 0 5 ) ;新兵组肾素活性、血管紧张素Ⅱ及醛固酮水平明显回落 ,但血管紧张素Ⅱ水平仍高于跳伞前 (P <0 0 5 ) ,且明显高于老兵组 (P <0 0 1)。　结论　跳伞训练中新兵较老兵处于更强烈的应激状态 ;严重的跳伞应激可通过一定的跳伞训练而得以减轻     

不同模拟飞行训练科目飞行员心率和心率变异性的变化

目的 比较特情处置模拟飞行训练与起落航线飞行过程中心率及心率变异性的变化,探讨模拟飞行训练过程中飞行员心理应激水平的变化特点.方法 随机选取参加飞行模拟训练训练的飞行员20名,连续动态记录心电信号,对其在安静时及起落航线飞行、特情处置飞行2种科目模拟飞行前、中、后的心率及短时程心率变异性时域及频域参数进行分析.结果 1)飞行前6 min,HR、RMSSD、LFnu及LF/HF升高,SDNN、HRVI降低(P＜0.05);飞行前特情飞行与起落飞行相比,RMSSD较低,LF/HF较高(P＜0.01).2)飞行过程中HR和HRV各指标均出现升高(P＜0.05),各指标在2种科目之间无显著差异(P＞0.05);3)飞行后,各项指标均有所恢复,但未至安静时水平(P＜0.05).特情处置飞行恢复较起落飞行更慢(P＜0.01).结论 飞行前发生应激反应并伴有较轻的心理疲劳,特情处置飞行前应激反应明显高于起落航线飞行;飞行中出现较高的心理反应及心理疲劳,但2科目间无明显差异;飞行后应激水平有所恢复,但特情处置飞行的恢复速度较起落飞行慢.     

空降兵新兵跳伞应激对血浆腺垂体激素及性腺激素含量的影响

目的：探讨空降兵新兵群体跳伞应激状态下腺垂体激素及性腺激素的变化。方法：将54名新兵分为3组，即对照组（22人）、试验1组（12人）、试验2组（20人）。分别在跳伞前24h、登机前和着陆后即刻抽取肘正中静脉血10ml，采用放免法测定黄体生成素（LH）、生长激素（HGH）、促卵泡生成素（FSH）、泌乳素（PRL）、雌二醇（E2）和睾丸酮（T）水平。结果：①试验1组、试验2组腺垂体激素均较对照组明显增加（P＜0．01）；试验2组促卵泡生成素和生长激素水平较试验1组增加（P＜0．01），而黄体生成素和泌乳素在两试验组差异不显著。②性腺激素在跳伞应激时的变化不明显。结论：对新伞兵跳伞应激的生理、心理因素的影响不容忽视。     

飞行员在地面和飞行中的心率变异分析

目的 观察不同飞行状态下反映心脏自主神经调节功能的心率变异性(HRV)特点,探讨以此评价飞行应激的可能性。方法 记录21名飞行员飞行前、中、后及起飞、平飞、着陆时的连续心电图,进行频谱分析,计算低频成分(LF)和高频成分(HF)之比值。结果 飞行中的LF/HF明显高于飞行前和飞行后,平飞时LF/HF明显高于起飞和降落。结论 飞行中,特别是起飞和降落时交感神经活动显著增强,这与飞行的难度和强度有关。     

卧床不同训练方法对心血管自主神经调节变化的影响

目的以心率变异性 (HRV)频域变量 ,作为定量评价心血管自主神经调节变化的指标 ,观察卧床条件下 ,不同训练方法对心血管自主神经调节变化的影响。方法被试者为 1 5名年龄 1 9～ 2 2岁的健康男性 ,分为对照组、放松训练组和低氧训练组 ,每组 5人 ,头低位 (- 6°)卧床模拟失重时的心血管变化。在对照期 (第 2天 )、卧床期 (第 3、1 4、1 8天 )和恢复期 (第 7天 )记录 2 4h动态心电图 ,采用自回归模型进行 2 4h全程、放松和低氧训练前、中、后的心率变异性谱分析 ,其标准化的低频 (LF % ,0 .0 4～ 0 .1 5Hz)成分表示心交感神经的紧张度 ,标准化的高频 (HF % ,0 .1 5～ 0 .40Hz)成分独立地反映心迷走神经的活性 ,LF/HF的比值表明交感和迷走神经张力的平衡关系。结果卧床期对照组的LF %和HF %成分显著下降 (P <0 .0 5) ,LF/HF无明显变化。放松组在放松训练中HRV谱的HF %成分明显增加 (P <0 .0 5) ,而低氧组在低氧训练中 ,LF %成分显著增加 (P <0 .0 5)。结论卧床使交感和迷走神经的活性都降低 ,放松训练明显提高了迷走神经的兴奋性 ,而低氧训练明显提高了交感神经的兴奋性。提示 ,HRV指标有可能作为定量评价失重对抗措施的客观指标 ,值得进一步深入研究。     

空降兵新兵跳伞应激对血浆心钠素、血管紧张素Ⅱ、内皮素及胃泌素含量的影响

目的 探讨空降兵新兵群体跳伞应激状态下心钠素（ANP）、血管紧张素Ⅱ（AngⅡ)、内皮素（ET）及胃泌素（SHG）含量的变化规律。方法 将54名新兵分为3组，即对照组22人（示范伞兵14人，非示范伞兵8人），试验1组12人（示范伞兵5人，非示范伞兵7人），试验2组20人（示范伞兵9人，非示范伞兵11人）。分别在跳伞前24h、登机前和着陆后即刻抽取肘正中静脉血10ml，采用放射免疫法测定ANP、AngⅡ、ET及SHG水平。结果 试验1组、试验2组ANP、AngⅡ、ET及SHG均较对照组明显增加（P＜0.01)；试验2组ANP、AngⅡ及SHG较试验1组增加（P＜0.01)，而ET在两试验组差异不显著。示范伞兵的SHG水平在跳伞前24h与着陆后即刻均较非示范伞兵低（P＜0.05)。结论 跳伞应激时ANP、AngⅡ、ET及SHG的变化研究对空降兵部队开展预防心身疾病和神经症等心理卫生工作有指导作用。     

Ocular problems in military free fall parachutists

Military free fall parachutists may be unaware of the risk of corneal freezing and desiccation keratitis should their goggles come off during free fall in subfreezing temperatures. We determine the incidence of ocular difficulties in military free fall parachutists and the role freezing temperatures may play in causing these problems. We found that 79% of those who responded to the survey had lost their goggles at least once during free fall and 69% experienced ocular symptoms after goggle loss. Analysis shows a 30-fold increase in the duration of symptoms in subfreezing vs. above-freezing temperatures, with the odds of the ground mission being affected at 7.3 per 100 jumps in the subfreezing group. The rate of goggles coming off per jump is 3.3 times less with >75 jumps. Contact lenses are not protective and photorefractive keratectomy was not detrimental.     

Incidence of airsickness among military parachutists

This study describes the incidence of airsickness among military parachutists and analyzes the factors involved in its occurrence. Each of 45 healthy male subjects (28 students and 17 advanced parachutists) was studied. Each student participated in five parachute-jump exercises (one daily) and each advanced parachutist participated in one exercise only (proficiency). A questionnaire used for the diagnostic evaluation of motion sickness symptoms was completed by the subjects after each training exercise. A positive diagnosis of airsickness was established for 64% of the students on their first jump and for 35% of the advanced paratroopers on their proficiency jump. By the fifth jump, only 25% of the students experienced airsickness. This suggests that some students developed tolerance to airsickness after five consecutive exposures to inflight vestibular stimulation. Airsickness among student and advanced paratroopers occurred during the transport flight. This can be attributed to vestibular stimulation resulting from the aircraft maneuvers and inflight air turbulence.     

模拟跳伞踝关节压力与体质指数的相关性

目的 探讨跳伞半蹲式着陆时内、外踝压力大小与受试者体质指数之间的相关性.方法 测量13名现役军事跳伞员的身高、体重,计算BMI.受试者分别从0.6m高平台跳下,模拟跳伞半蹲式着陆,记录着陆时双足内、外踝所受压力. 结果 在模拟跳伞半蹲式着陆时双足内踝所受平均压力明显高于外踝（t=9.605、9.392,P＜0.01）.左足内踝、右足内踝、左足外踝、右足外踝所受平均压力与体质指数之间的相关系数分别为0.898、0.890、0.824、0.833,且均具有直线相关性.结论 模拟跳伞半蹲式着陆时内、外踝所受压力与体质指数呈正相关.为降低跳伞着陆时踝关节损伤风险,空降兵应积极控制体重.     

Cardiac autonomic imbalance in an overtrained athlete

PURPOSE: In order to investigate overtraining-related adaptations in the autonomic nervous system, cardiac autonomic activity was examined in a junior cross-country skier who presented with reduced performance in competitions, early breathlessness during training sessions, and accumulated central fatigue. METHODS: Power spectral analysis of heart rate variability (HRV) was performed before, when overtrained (OT), and after recovery (Rec). RESULTS: In the overtrained state, high frequency (HF) and total powers in the lying position were higher compared with before and after. In normalized units, the increased HF in OT was even more prominent and clearly higher than in any control subject, and it was reversed in Rec. Resting heart rate was slightly reduced in OT and returned to baseline in Rec. CONCLUSIONS: The shift toward increased heart rate variability, particularly in the HF range, together with a reduced resting heart rate suggest a cardiac autonomic imbalance with extensive parasympathetic modulation in this athlete when overtrained.     

Effects of aerobic exercise training on 24 hr profile of heart rate variability in female athletes

BACKGROUND: The aim of this study was to investigate the effects of exercise training on autonomic regulation of heart rate under daily life conditions. METHODS: Twenty-six healthy female athletes (age 24.5 +/- 1.9 yrs) involved in regular physical activity were recruited during a period of yearly rest and randomly assigned to a five-week aerobic exercise training program (n = 13) or to a non-exercise control group (n = 13). MEASURES: Before and after the five-week training, all subjects underwent a bycicle ergometer stress test and a 24-hour dynamic ECG monitoring. Autonomic regulation of heart rate has been investigated by means of both time and frequency domain analyses of heart rate variability (HRV). Spectral analysis of R-R interval variability (autoregressive algorithm) provided markers of sympathetic (low frequency, LF, 0.10 Hz) and parasympathetic (high frequency, HF, 0.25 Hz) modulation of the sinus node. RESULTS: Trained subjects showed a reduced heart rate response to submaximal workload. Before training there was no significant difference between the two groups. After training resting heart rate did not significantly differ between trained and untrained subjects. No significant differences were observed in the different time domain indexes of heart rate variability. The day-night difference in SD and SDRR were significantly less in the trained as compared to the untrained group. Normalized LF and HF components did not significantly differ between trained and untrained subjects, during the awake period. The decrease in the LF and the increase in the HF component during nighttime were significantly less in the trained group. The LF/HF ratio was significantly decreased during the night in the untrained group whereas it was not significantly different from the awake state in the trained group. CONCLUSIONS: These findings of the relative night-time increase in LF and the decrease in the day-night difference in time domain indexes of heart rate variability suggest that, in young female athletes, exercise training is able to induce an increase in the sympathetic modulation of the sinus node which may coexist with signs of relatively reduced, or unaffected, vagal modulation.     

Autonomic adaptations to intensive and overload training periods: a laboratory study

PURPOSE: Looking for practical and reliable markers of fatigue is of particular interest in elite sports. One possible marker might be the autonomic nervous system activity, known to be well affected by physical exercise and that can be easily assessed by heart rate variability. METHODS: We designed a laboratory study to follow six sedentary subjects (32.7 +/- 5.0 yr) going successively through 2 months of intensive physical training and 1 month of overload training on cycloergometer followed by 2 wk of recovery. Maximal power output over 5 min (Plim5'), VO(2) and standard indices of heart rate variability were monitored all along the protocol. RESULTS: During the intensive training period, physical performance increased significantly VO(2peak) : +20.2%, < 0.01; Plim5': +26.4%, < 0.0001) as well as most of the indices of heart rate variability (mean RR, Ptot, HF, rMSSD, pNN50, SDNNIDX, SDNN, all < 0.05) with a significant shift in the autonomic nervous system toward a predominance of its parasympathetic arm (LF/HF, LFnu, HFnu, < 0.01). During the overload training period, there was a stagnation of the parasympathetic indices associated to a progressive increase in sympathetic activity (LF/HF, < 0.05). During the week of recovery, there was a sudden significant rebound of the parasympathetic activity (mean RR, HF, pNN50, rMSSD, all < 0.05). After 7 wk of recovery, all heart rate variability indices tended to return to the prestudy values. CONCLUSION: Autonomic nervous system status depends on cumulated physical fatigue due to increased training loads. Therefore, heart rate variability analysis appears to be an appropriate tool to monitor the effects of physical training loads on performance and fitness, and could eventually be used to prevent overtraining states.     

Heart rate variability: response following a single bout of interval training

We investigated the effect of exercise on heart rate variability by analysing the heart rate power spectrum prior to, and 1 and 72 h following, an interval training session. Subjects initially performed a graded test to exhaustion to determine maximal oxygen uptake (VO(2) max) and the running speed at which VO(2) max was first attained (vVO(2) max). The training session was completed on a separate day and comprised six 800 m runs at 1 km x h (-1) below vVO(2) max. Prior to the training session (pre), 1 h following the training session (+ 1h), and 72 h following the training session (+ 72 h), subjects sat quietly in the laboratory for 20 min whilst breathing frequency was maintained at 12 breath x min (-1). Cardiac cycle R-R interval data were collected over the final 5 min of each 20 min period and analysed by means of autoregressive power spectral analysis to determine the high frequency (HF) and low frequency (LF) components of heart rate variability. Heart rate was higher, and the standard deviation of the R-R intervals was lower, at + 1 h than for pre or + 72 h (p < 0.05). The HF and the LF components of heart rate variability were also lower (p < 0.05) for + 1 h than for pre or + 72 h when the data were expressed in ms(2). However, no changes in the LF:HF ratio were observed, and the changes in the HF and LF components disappeared when the data were expressed as a fraction of the total power. Whilst these findings illustrate the importance of controlling the timing of exercise prior to the determination of heart rate variability, the time course of the post-exercise heart rate variability response remains to be quantified.     

Evaluation of the effect of flights in supersonic fighters on sinus rhythm variability parameters

Heart rate variability is a widely used method to evaluate vagal and sympathetic influences on the heart. The purpose of this study was to assess the relationship of autonomic nervous system components' interaction in supersonic fighter pilots by means of a sinus rhythm variability analysis. The following frequency domain parameters were analyzed: low-frequency (LF) power spectral of 0.05 to 0.15 Hz (ms2); high-frequency (HF) power spectral of 0.15 to 0.45 Hz (ms2); LF and HF power spectral index; total spectral power (HF + LF); percent, LF distribution in total spectral power; percent HF, HF distribution in total spectral power; and an average heart rate per minute. The study comprised 30 healthy military pilots (age, 24-48 years) in whom heart rate variability parameters were determined 10 to 12 minutes before take off, 10 to 12 minutes after four successive flights, and 1, 2, and 12 to 16 hours after completing the flights. The control group was comprised of 20 healthy nonpilots (age, 24-49 years). The statistical significance was estimated by means of the following methods: Student's t test for normal distribution and a rank test for the non-normal one (between the groups of the same subjects); and the Cochran-Cox test for normal distribution and the Wilcoxon test for the non-normal one (between the groups of different subjects). Higher activity of sympathetic components of the autonomic nervous system was shown in pilots in the course of the first examination before flights as compared with the controls (higher LF, LF/HF, percent LF). Predominance of the sympathetic nervous system in pilots might reflect adaptation to repeated short-term exposures to high values of accelerations acting in head-leg axis.     

心率变异性与运动病关系的研究

目的　探讨心率变异性与运动病的关系。方法　根据出海实习学员运动病的发生情况 ,将学员分为运动病组和对照组各 2 0人 ,采集安静状态下的 5 2 0次窦性心搏 ,应用心率变异时域、频域分析方法评价自主神经功能状态。结果　运动病组时域指标 RR间期平均值的标准差 (SDNN)、相邻 RR间期差值的均方根 (r MSSD)、相邻 RR间期相差大于 5 0 m s占总心动周期数的百分比 (PNN50 )、HRV指数(HRVI)和频域指标低频 (L F)、高频 (HF)、总功率谱密度 (TP)均显著高于对照组 (P<0 .0 5 )。 RR间期平均值 (MRR)、极低频 (VL F)、低频与高频的比值 (L F/ HF)在两组间差异无显著性 (P>0 .0 5 )。结论　自主神经功能状态对运动病的发生存在明显的影响 ,迷走神经张力过高与运动病的发生有密切关系。心率变异性检测可以作为运动病易感性重要的预测指标。     

Night heart rate variability during overtraining in male endurance athletes

AIM: The purpose of the study was to examine whether an unaccustomed increase in training volume would result in characteristics changes in heart rate variability (HRV), in order to determine if this marker can be used to diagnose overtraining. METHODS: Nine experienced endurance athletes increased their usual amount of training by 100% within 4 weeks. Night ECG was recorded before (baseline) and after (OVER) this period of overload, and after 2 weeks of recovery (REC). RESULTS: We diagnosed overtraining in 6 subjects using both physiological and psychological criteria. No difference was noted in heart rate for night periods (56+/-12, 55+/-10 and 53+/-15 bpm, respectively; p>0.05). We found no significant changes of LF/HF (1.10+/-0.92, 0.96+/-0.57 and 0.59+/-0.43, respectively; p>0.05) or HF expressed in normalized units (54.81+/-20.12, 53.81+/-11.35 and 66.15+/-15.12%, respectively; p>0.05). CONCLUSION: In the conditions of the present study, HRV during sleep does not seem to be a valid marker of overtraining in male endurance athletes. Before concluding to the uselessness of this tool in the monitoring of the syndrome, longitudinal studies with elite or sub-elite athletes are needed to determine if spontaneously developed overtraining results in the same response.