急性轻、中度缺氧暴露对人情绪的影响
作者：李学义 吴兴裕 付川 沈小凤 吴燕红 王涛
单位：
关键词：缺氧；情绪；情绪状态问卷；状态—焦虑问卷
航天医学与医学工程000101摘要：目的 研究急性轻、中度缺氧对人的情绪及焦虑状态的影响。方法 利用低压舱模拟300 m(对照)、2800 m、3600 m、4400 m高度缺氧暴露1 h，采用情绪状态问卷(POMS)和状态—焦虑问卷(S-AI)，考察了18名健康男性青年受试者的情绪变化。结果 随着高度的增加，POMS问卷中紧张—焦虑(T)，困惑—迷茫(C)和疲惫—惰性(F)消极情绪状态值及S—AI得分逐渐增加，而其中的积极情绪状态值即有力—好动(V)得分则依此下降(P<0.05或P<0.01)，但POMS中愤怒-敌意(A)和抑郁-沮丧(D)的得分并无显著变化(P>0.05)。2800 m 急性暴露的即刻，紧张-焦虑(T)和S-AI得分显著高于对照水平(P<0.05)，而暴露1 h后又下降至地面水平。结论 急性轻、中度缺氧暴露1h在2800 m高度水平即对人的情绪及心境产生负面影响，随着高度的增加上述影响进一步加重。
, 百拇医药
中图分类号：R852.11 文献标识码：A
文章编号：1002-0837(2000)01-0001-05
Effects of Acute Mild and Moderate Hypoxia on Human Mood State
LI Xue-yi，WU Xing-yu，WU Yan-hong，WANG Tao
(Department of Aerospace Medicine DAM,Fourth Military Medical University FMMU,Xi'an 710032)
FU Chuan，SHEN Xiao-feng
(Department of Steward Medicine,China Southwest Airlines,Chengdu 610202)
, 百拇医药
Abstract:Objective To explore the effects of acute mild and moderate hypoxia on human mood state.Method The mood states of 18 healthy male volunteers were evaluated by self-assessment questionnaires,profile of mood state (POMS) and state anxiety inventory (S-AI) after random exposure to simulated altitude of 300 m (control)，2800m,3600 m and 4400 m for 1 h in a hypobaric chamber.Result The data at 300 m level were taken as the baseline control.The negative mood state factor points (tension,fatigue etc.) increased gradually as the altitude level increased while V (vigor-activity) points had a tendency to decrease (P<0.05 or P<0.01).No significant difference was found in the points of (D,A) even under exposure to 4400 m(P>0.05).At the early period of 2800 m exposure the tension points of POMS and S-AI scores were higher than those of control level (P<0.05) then dropped to baseline level when exposure to this altitude for 1 h.Conclusion Exposure to acute mild hypobaric hypoxia at 2800 m for 1 h has adverse effect on mood state of healthy person and the negative effect was further aggravated with the increment of altitude level.
, 百拇医药
Key words：hypoxia;emotions;profile of mood state;state anxiety inventory
The rapid advances in powered flight in military and civilian aviation have made it possible to more crews and passengers to ascend rapidly to high altitude than ever;the technologic advance that occurred and continues to occur demands the development of parallel medical system to serve those who fly.It is well known that there are extensive highland regions in our country,and with one sixth of these areas are high above 3000 m.The effects of hypoxia on human cognitive performance must be further assessed because human beings have to work and live in environments with reduced oxygen levels.
, http://www.100md.com
Although effects of a rapid ascent to high terrestrial altitude on cognition have been well documented[4～12],the generalizations of effects of altitude on mood,behavior and cognitive functions such as memory,attention,thinking and so on are complicated by differences between studies including the specific tasks or dimensions measured in the response to altitude sojourns.Emotion which reflect the shifting of external and internal environment and mood state might be more sensitive to hypoxia than cognitive functions,so investigations designed to measure mood state changes during acute hypoxia are needed.Therefore this study is aimed to describe the effects of hypoxia on mood state by self-assessment questionnaires,profile of mood state (POMS) and state anxiety inventory (S-AI).
, 百拇医药
Method
Subjects The subjects were eighteen healthy young male non-smoking and non-drinking freshmen of the Fourth Military Medical University,aged 16～18 years.All had normal or corrected to normal vision and normal color vision.All were normal residents at altitude below 300 m and none have been to plateau prior to this trial.Participation in the experiments and exposure was voluntary.
Altitude Simulation The test were carried out in a hypobaric chamber afforded by DAM,FMMU.The subjects were randomly exposed to hypoxia equivalent to altitudes 300 m,2800 m,3600 m and 4400 m,meanwhile they were asked to answer the questionnaires twice in 1 h period at each altitude(5 and 60 min after ascent to altitude respectively).The questionnaires to be finished in this experiment required about 5～7 min to complete.The order of altitude level presentation was randomly chosen by the chamber controller and without knowledge of the subjects and experimenters inside the chamber.The project and experimental protocol were approved by the department of technology and engineering of DAM.The hypobaric chamber ascended to the test altitude at a speed of 15 m/s and maintained for 1 h.After having finished all tests,the hypobaric chamber descended to the ground level (300 m high above sea level in Xi'an) at a speed of 5 m/s.Subjects were told to swallow and do Valsalva maneuver to prevent otitic Barotrauma durig the descent.The chamber was continuously ventilated with fresh air;noise:75 dB(A);relative humidity and temperature were maintained at 25%～43% and 20.4℃～25.1℃ respectively.All subjects wore flight headgear and earplugs inside the chamber to shield off of noise.All tests were performed at 18:30～21:30 to eliminate influence of circadian rhythm.The time between two ascents was longer than 48 h.
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Procedure To gain familiarity with the facilities,tests and environment,all subjects practiced the questionnaires for 2～3 times prior to the experiment.They were briefly told about the purpose and process of the experiment in order to gain their sincere cooperation.Analysis of variance for repeated measurement was carried out to compare with the baseline data of 300 m to minimize confounding of other factors,i.e.noise,fatigue,learning effects etc.All the test operations were carried out in standard order and with fixed apparatuses by same instructor in order to reduce errors.
, http://www.100md.com
Questionnaires The POMS is a questionnaire from neurobehavioral core test battery of WHO organized by Mcnair et al[1,2].Its Chinese version consists of 65 adjective words with 5-point scale degrees of agreement,resulting in 6 kinds of mood statesT:tension-anxiety;D:depression-dejection;A:anger-hostility;V:vigor-activity;
F:fatigue-inertia;C:confusion-bewilderment.The Chinese version of the state anxiety inventory Questionnaires (S-AI)[3] composed by 20 titles with 4-point scale was used for estimation of anxiety of mood state.
, http://www.100md.com
Statistical analyses The analysis of variance (ANOVA) and two-tailed paired T-test were used on the scores of questionnaires to analyze the effects of hypoxia on mood state.All statistical analyses were carried out using Statistical Package for the Social Science(SPSS).Statistical analysis consisted of scores of means and standard deviation(
±s),and auto-control was used to compare differences between control and each altitude group based on the subject's own baseline points.For all analyses probability level of less than 0.05 was accepted as significant.
, 百拇医药
Result
Changes of POMS after 1 h exposure to different altitudes The effects of acute hypoxia on POMS were shown in tab 1.Increased points of F(fatigue-inertia) were found after exposure to 2800 m for 1 h while V(vigor-activity) scores decreased (P<0.05),however the other factor points were not affected at this altitude.The T(tension-anxiety) and F(fatigue-inertia) scores were significantly increased as compared with baseline at control level when exposed to 3600 and 4400 m for 1 h(P<0.05 or P<0.01),and the higher altitude was,the higher the points of above mentioned factors.However the scores of A and D did not show any appreciable difference as compare with the baseline even at 4400 m,and C points also did not change except under exposure to 4400 m(P<0.05).Yet the V(vigor-activity) scores were significantly decreased especially under exposure to 4400 m (P<0.01).
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Table 1 Effect of exposure to acute hypoxia at different altitude for 1 h on human POMS(±s,n=18) mood factor
control
2800 m
3600 m
4400 m
T(tension-anxiety)
2.81±1.47
4.31±1.35
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5.50±2.00*
8.31±5.40**
D(depression-dejection)
1.13±1.26
1.75±1.94
2.44±3.59
3.13±4.31
A(anger-hostility)
1.25±1.69
2.19±2.37
2.75±2.86
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2.81±2.61
V(vigor-activity)
21.13±3.59
18.87±5.32*
17.73±4.58**
16.18±2.48**
F(fatigue-intention)
1.50±0.86
3.56±1.36*
4.37±2.82**
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6.56±3.68**
C(confusion-bewilderment)
3.12±3.20
3.87±3.66
4.68±3.66
6.81±4.15**
*P<0.05，**P<0.01，as compared with controlTable 2 Changes of POMS and S-AI during exposure to 2800 m altitude (±s,n=18) mood factor
, http://www.100md.com
control
exposure(min)
5
60
T(tension-anxiety)
2.81±1.47
6.25±2.32**
4.31±1.35
D(depression-dejection)
1.13±1.26
1.43±1.05
, http://www.100md.com
1.75±1.94
A(anger-hostility)
1.25±1.69
1.20±1.23
2.19±2.37
V(vigor-activity)
21.13±3.59
22.24±4.59
18.87±5.32*
F(fatigue-intention)
1.50±0.86
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1.42±1.29
3.56±1.36*
C(confusion-bewilderment)
3.12±3.20
3.09±4.28
3.87±3.66
S-AI
20.33±5.87
28.75±6.57*
24.33±7.73
*P<0.05，**P<0.01，as compared with controlTable 3 Effects of exposure to acute hypoxia at different altitude for 1 h on S-AI points(±s,n=18) baseline
, 百拇医药
altitude(m)
2800
3600
4400
20.33±5.87
24.33±7.73
30.22±11.82**
31.62±11.66**
*P<0.05，**P<0.01，as compared with control
Changes of S-AI after 1 h exposure to different altitudes Improved scores of state anxiety inventory at increased altitudes were show in the tab 3.Significant increase was found between baseline and 2800 m exposure for 1 h(P<0.05),and further increases were found at 3600 m and 4400 m(P<0.01).
, 百拇医药
Changes of POMS and S-AI during 1 h exposure to 2800 m The change of POMS and S-AI with time during 1 h exposure to 2800 m was shown in tab 2.At the beginning of exposure,the T points of POMS and A-SI scores were significantly higher than those of baseline (P<0.05) ，then dropped to control level when exposed for 1 h (P>0.05).The V point had a similarity tendency during the early period of exposure,but was not statistically significant (P>0.05).Increased points of F(fatigue-inertia) and decreased scores of V(vigor-activity) were found when exposure to 2800 m for 1 h (P<0.05).
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Discussion
The questionnaire used in this experiment is a reliability and validity method for assessing the effects of mood states in environment with reduced oxygen and behavioral toxicology[1～3].It appeared well to reflect the changes of mood states exposed to acute hypoxia.Effects of acute hypoxia exposure on mood and performance have been well documented[4～12],but there are conflicting results in the literature regarding the effect of hypobaric hypoxia on cognitive and mood state.Psychological and behavioral changes resulting from the effects of hypoxia often include increases in euphoria irritability,hostility and impairment of cognitive functions such as attention,thinking and memory have been reported by a member of authors[5],In a recent study,shukitt et al reported normobaric 13% FIO2 could produce shorter decrements in cognitive function and mood state[10，11].However there are also a number of reports indicating that performance is unaffected at altitude up to 3600 m[12].As mentioned above,there is much uncertainty as to the level of hypoxia that will cause noticeable impairment.Gongga airdrome in Tibet of our country is 3541 m above sea level and Bangda airdrome(4330 m )is one of the highest airdrome in the world.Exposure to high terrestrial altitude associated with cognitive function decrement and mood states changes,such impairment in aviators could be a safety hazard.For this reason the aim of this study was to evaluate the changes of profiles of mood states of 18 healthy volunteers after exposed to different altitude(300 m,2800 m,3600 m and 4400 m) of hypoxia for 1 h in order to cope with the actual problems of the southwest airline.
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The results of this experiment suggested that the negative mood factor (T,F,C) points increased progressively and the positive mood (V)points decreased gradually during the hypoxia exposure for 1 h,and the scores of S-AI had a similar tendency to POMS.It indicated that mild and moderate hypoxia may have a negative effect on mood state.However,no general change was found in the points of D,A despite the fact that hypoxia was equivalent to an altitude of 4400 m.This may be partially because the subjects know much about this experiment and cooperated sincerely and partially by the reason of competition in the process with others.The time course of POMS exposure to 2800 m showed that the negative factor point(T) and S-AI scores increased at the beginning of the exposure,it suggested that the subjects may be nervous in a new environment and worried about what the altitude would be.Yet the V points had a tendency to increased at the beginning of exposure then dropped down toward the end of the exposure,it suggested that hypoxia especially mild hypoxia as a stress may produce some temporary positive effects on cognitive and mood state,but it can't maintain till the end of exposure.
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About the problem of threshold of hypoxia,JIA SiGuang et al,suggested that during exposure to hypoxic environment,guarantee range of performance was 3000 m,and the permitted range was 4000 m.Based on this suggestion,they established corresponding physiological protection criteria[8].Foweler etc pointed out that the threshold of maintaining normal performance was 9750 ft(2972 m)[4].Shukitt and Banderet reported significant reduction in unhappiness after ascending to a mountaintop laboratory at 4300 m,while aggressiveness was unchanged or reduced[12].The overall data from this experiment indicated there were negative effects on mood state even exposure to 2800 m for 1 h,These effects were further aggravated under exposure to 3600 m or 4400 m,this is quite similar to Green RG and Morgan DR's reports who found that when oxygen concentration was lowered to 13%(equivalent to 3400 m) at normal air pressure,adverse effects on human cognition,efficiency and mood may be brought about[10].The relationship between mood state and cognitive should be further assessed.Complementary studies and a larger sample of subjects should be involved in further experiments in order to get more information.
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[References]
[1]Mcnair DM,Lorr M,Droppleman LF.Profile of mood states[J].Education and Industrial Test Service,San Diego,1971:3～11
[2]LIANG Youxin.Introduction to the WHO neurobehavioral core test battery[J].Journal of Industrial Hygiene and Occupational Disease,1987,13(6):331～339
梁有信.介绍WHO推荐的神经行为核心测验组合[J].工业卫生与职业病杂志,1987,13(6):331～339
[3]SHU Liang.Questionnaires of state anxiety inventory[J].Chinese Journal of Psychohygien,1993,(suppl):205～207
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舒 良.状态-特质焦虑问卷.见：心理卫生评定量表手册，中国心理卫生杂志，1993,增刊，205～207
[4]Fowler B,Kelso B,Elcombe DD et al.The threshold for hypoxia effects on perceptual-motor performance[J].Human Factor,1987,29:61～66
[5]Bahrke-MS,Shukitt-Hale-B.Effects of altitude on mood,behaviour and cognitive functioning[J].Sports-Med,1993,16(2)97～125
[6]WU Xingyu,LI Xueyi,HAN Liping et al.Effects of acute moderate hypoxia on human performance of arithmetic[J].Space Medicine & Medical Engineering,1998,11(6):391～395
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吴兴裕，李学义，韩厉萍等.急性中度缺氧对人计算能力影响的研究(英文)[J].航天医学与医学工程,1998,11(6):391～395
[7]Crowley JS,Wesensten N,Kamimori G et al.Effect of high terrestrial altitude and supplemental oxygen on human performance and mood[J].Aviate Space Environ Med,1992,63:696～701
[8]JIA Siguang.Some new progress in the systematic study of acute hypoxia at altitudes[J].Space Medicine & Medical Engineering,1989,2(1):1～9
贾司光.高空急性缺氧的系统研究[J].航天医学与医学工程,1989,2(1):1～9
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[9]Green RG,Morgan DR.The effects of mild hypoxia on a logical reasoning task[J].Aviation space and Environ mantal Medicine,1985,56:1004～8
[10]Shukitt BL,Burse RL,Banderet LE et al.Cognitive performance,mood states and altitude symptomatology in 13-21% oxygen environments.Natick,MA:U.S.Army Res.inst.of Environmental Med,1988,Technical Report no,T18～88
[11]Shukitt BL,Banderet LE.Mood states at 1600 and 4300 meters terrestrial altitude[J].Aviate Space Eviron Med,1988,59:530～532
[12]Paul MA,Fraser WD.Performance during mild acute hypoxia[J].Aviate Space Environ Med,1994,65:891～899
Recieved date:1999-03-15, 百拇医药
单位：
关键词：缺氧；情绪；情绪状态问卷；状态—焦虑问卷
航天医学与医学工程000101摘要：目的 研究急性轻、中度缺氧对人的情绪及焦虑状态的影响。方法 利用低压舱模拟300 m(对照)、2800 m、3600 m、4400 m高度缺氧暴露1 h，采用情绪状态问卷(POMS)和状态—焦虑问卷(S-AI)，考察了18名健康男性青年受试者的情绪变化。结果 随着高度的增加，POMS问卷中紧张—焦虑(T)，困惑—迷茫(C)和疲惫—惰性(F)消极情绪状态值及S—AI得分逐渐增加，而其中的积极情绪状态值即有力—好动(V)得分则依此下降(P<0.05或P<0.01)，但POMS中愤怒-敌意(A)和抑郁-沮丧(D)的得分并无显著变化(P>0.05)。2800 m 急性暴露的即刻，紧张-焦虑(T)和S-AI得分显著高于对照水平(P<0.05)，而暴露1 h后又下降至地面水平。结论 急性轻、中度缺氧暴露1h在2800 m高度水平即对人的情绪及心境产生负面影响，随着高度的增加上述影响进一步加重。
, 百拇医药
中图分类号：R852.11 文献标识码：A
文章编号：1002-0837(2000)01-0001-05
Effects of Acute Mild and Moderate Hypoxia on Human Mood State
LI Xue-yi，WU Xing-yu，WU Yan-hong，WANG Tao
(Department of Aerospace Medicine DAM,Fourth Military Medical University FMMU,Xi'an 710032)
FU Chuan，SHEN Xiao-feng
(Department of Steward Medicine,China Southwest Airlines,Chengdu 610202)
, 百拇医药
Abstract:Objective To explore the effects of acute mild and moderate hypoxia on human mood state.Method The mood states of 18 healthy male volunteers were evaluated by self-assessment questionnaires,profile of mood state (POMS) and state anxiety inventory (S-AI) after random exposure to simulated altitude of 300 m (control)，2800m,3600 m and 4400 m for 1 h in a hypobaric chamber.Result The data at 300 m level were taken as the baseline control.The negative mood state factor points (tension,fatigue etc.) increased gradually as the altitude level increased while V (vigor-activity) points had a tendency to decrease (P<0.05 or P<0.01).No significant difference was found in the points of (D,A) even under exposure to 4400 m(P>0.05).At the early period of 2800 m exposure the tension points of POMS and S-AI scores were higher than those of control level (P<0.05) then dropped to baseline level when exposure to this altitude for 1 h.Conclusion Exposure to acute mild hypobaric hypoxia at 2800 m for 1 h has adverse effect on mood state of healthy person and the negative effect was further aggravated with the increment of altitude level.
, 百拇医药
Key words：hypoxia;emotions;profile of mood state;state anxiety inventory
The rapid advances in powered flight in military and civilian aviation have made it possible to more crews and passengers to ascend rapidly to high altitude than ever;the technologic advance that occurred and continues to occur demands the development of parallel medical system to serve those who fly.It is well known that there are extensive highland regions in our country,and with one sixth of these areas are high above 3000 m.The effects of hypoxia on human cognitive performance must be further assessed because human beings have to work and live in environments with reduced oxygen levels.
, http://www.100md.com
Although effects of a rapid ascent to high terrestrial altitude on cognition have been well documented[4～12],the generalizations of effects of altitude on mood,behavior and cognitive functions such as memory,attention,thinking and so on are complicated by differences between studies including the specific tasks or dimensions measured in the response to altitude sojourns.Emotion which reflect the shifting of external and internal environment and mood state might be more sensitive to hypoxia than cognitive functions,so investigations designed to measure mood state changes during acute hypoxia are needed.Therefore this study is aimed to describe the effects of hypoxia on mood state by self-assessment questionnaires,profile of mood state (POMS) and state anxiety inventory (S-AI).
, 百拇医药
Method
Subjects The subjects were eighteen healthy young male non-smoking and non-drinking freshmen of the Fourth Military Medical University,aged 16～18 years.All had normal or corrected to normal vision and normal color vision.All were normal residents at altitude below 300 m and none have been to plateau prior to this trial.Participation in the experiments and exposure was voluntary.
Altitude Simulation The test were carried out in a hypobaric chamber afforded by DAM,FMMU.The subjects were randomly exposed to hypoxia equivalent to altitudes 300 m,2800 m,3600 m and 4400 m,meanwhile they were asked to answer the questionnaires twice in 1 h period at each altitude(5 and 60 min after ascent to altitude respectively).The questionnaires to be finished in this experiment required about 5～7 min to complete.The order of altitude level presentation was randomly chosen by the chamber controller and without knowledge of the subjects and experimenters inside the chamber.The project and experimental protocol were approved by the department of technology and engineering of DAM.The hypobaric chamber ascended to the test altitude at a speed of 15 m/s and maintained for 1 h.After having finished all tests,the hypobaric chamber descended to the ground level (300 m high above sea level in Xi'an) at a speed of 5 m/s.Subjects were told to swallow and do Valsalva maneuver to prevent otitic Barotrauma durig the descent.The chamber was continuously ventilated with fresh air;noise:75 dB(A);relative humidity and temperature were maintained at 25%～43% and 20.4℃～25.1℃ respectively.All subjects wore flight headgear and earplugs inside the chamber to shield off of noise.All tests were performed at 18:30～21:30 to eliminate influence of circadian rhythm.The time between two ascents was longer than 48 h.
, http://www.100md.com
Procedure To gain familiarity with the facilities,tests and environment,all subjects practiced the questionnaires for 2～3 times prior to the experiment.They were briefly told about the purpose and process of the experiment in order to gain their sincere cooperation.Analysis of variance for repeated measurement was carried out to compare with the baseline data of 300 m to minimize confounding of other factors,i.e.noise,fatigue,learning effects etc.All the test operations were carried out in standard order and with fixed apparatuses by same instructor in order to reduce errors.
, http://www.100md.com
Questionnaires The POMS is a questionnaire from neurobehavioral core test battery of WHO organized by Mcnair et al[1,2].Its Chinese version consists of 65 adjective words with 5-point scale degrees of agreement,resulting in 6 kinds of mood statesT:tension-anxiety;D:depression-dejection;A:anger-hostility;V:vigor-activity;
F:fatigue-inertia;C:confusion-bewilderment.The Chinese version of the state anxiety inventory Questionnaires (S-AI)[3] composed by 20 titles with 4-point scale was used for estimation of anxiety of mood state.
, http://www.100md.com
Statistical analyses The analysis of variance (ANOVA) and two-tailed paired T-test were used on the scores of questionnaires to analyze the effects of hypoxia on mood state.All statistical analyses were carried out using Statistical Package for the Social Science(SPSS).Statistical analysis consisted of scores of means and standard deviation(
±s),and auto-control was used to compare differences between control and each altitude group based on the subject's own baseline points.For all analyses probability level of less than 0.05 was accepted as significant., 百拇医药
Result
Changes of POMS after 1 h exposure to different altitudes The effects of acute hypoxia on POMS were shown in tab 1.Increased points of F(fatigue-inertia) were found after exposure to 2800 m for 1 h while V(vigor-activity) scores decreased (P<0.05),however the other factor points were not affected at this altitude.The T(tension-anxiety) and F(fatigue-inertia) scores were significantly increased as compared with baseline at control level when exposed to 3600 and 4400 m for 1 h(P<0.05 or P<0.01),and the higher altitude was,the higher the points of above mentioned factors.However the scores of A and D did not show any appreciable difference as compare with the baseline even at 4400 m,and C points also did not change except under exposure to 4400 m(P<0.05).Yet the V(vigor-activity) scores were significantly decreased especially under exposure to 4400 m (P<0.01).
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Table 1 Effect of exposure to acute hypoxia at different altitude for 1 h on human POMS(
±s,n=18) mood factorcontrol
2800 m
3600 m
4400 m
T(tension-anxiety)
2.81±1.47
4.31±1.35
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5.50±2.00*
8.31±5.40**
D(depression-dejection)
1.13±1.26
1.75±1.94
2.44±3.59
3.13±4.31
A(anger-hostility)
1.25±1.69
2.19±2.37
2.75±2.86
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2.81±2.61
V(vigor-activity)
21.13±3.59
18.87±5.32*
17.73±4.58**
16.18±2.48**
F(fatigue-intention)
1.50±0.86
3.56±1.36*
4.37±2.82**
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6.56±3.68**
C(confusion-bewilderment)
3.12±3.20
3.87±3.66
4.68±3.66
6.81±4.15**
*P<0.05，**P<0.01，as compared with controlTable 2 Changes of POMS and S-AI during exposure to 2800 m altitude (
±s,n=18) mood factor, http://www.100md.com
control
exposure(min)
5
60
T(tension-anxiety)
2.81±1.47
6.25±2.32**
4.31±1.35
D(depression-dejection)
1.13±1.26
1.43±1.05
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1.75±1.94
A(anger-hostility)
1.25±1.69
1.20±1.23
2.19±2.37
V(vigor-activity)
21.13±3.59
22.24±4.59
18.87±5.32*
F(fatigue-intention)
1.50±0.86
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1.42±1.29
3.56±1.36*
C(confusion-bewilderment)
3.12±3.20
3.09±4.28
3.87±3.66
S-AI
20.33±5.87
28.75±6.57*
24.33±7.73
*P<0.05，**P<0.01，as compared with controlTable 3 Effects of exposure to acute hypoxia at different altitude for 1 h on S-AI points(
±s,n=18) baseline, 百拇医药
altitude(m)
2800
3600
4400
20.33±5.87
24.33±7.73
30.22±11.82**
31.62±11.66**
*P<0.05，**P<0.01，as compared with control
Changes of S-AI after 1 h exposure to different altitudes Improved scores of state anxiety inventory at increased altitudes were show in the tab 3.Significant increase was found between baseline and 2800 m exposure for 1 h(P<0.05),and further increases were found at 3600 m and 4400 m(P<0.01).
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Changes of POMS and S-AI during 1 h exposure to 2800 m The change of POMS and S-AI with time during 1 h exposure to 2800 m was shown in tab 2.At the beginning of exposure,the T points of POMS and A-SI scores were significantly higher than those of baseline (P<0.05) ，then dropped to control level when exposed for 1 h (P>0.05).The V point had a similarity tendency during the early period of exposure,but was not statistically significant (P>0.05).Increased points of F(fatigue-inertia) and decreased scores of V(vigor-activity) were found when exposure to 2800 m for 1 h (P<0.05).
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Discussion
The questionnaire used in this experiment is a reliability and validity method for assessing the effects of mood states in environment with reduced oxygen and behavioral toxicology[1～3].It appeared well to reflect the changes of mood states exposed to acute hypoxia.Effects of acute hypoxia exposure on mood and performance have been well documented[4～12],but there are conflicting results in the literature regarding the effect of hypobaric hypoxia on cognitive and mood state.Psychological and behavioral changes resulting from the effects of hypoxia often include increases in euphoria irritability,hostility and impairment of cognitive functions such as attention,thinking and memory have been reported by a member of authors[5],In a recent study,shukitt et al reported normobaric 13% FIO2 could produce shorter decrements in cognitive function and mood state[10，11].However there are also a number of reports indicating that performance is unaffected at altitude up to 3600 m[12].As mentioned above,there is much uncertainty as to the level of hypoxia that will cause noticeable impairment.Gongga airdrome in Tibet of our country is 3541 m above sea level and Bangda airdrome(4330 m )is one of the highest airdrome in the world.Exposure to high terrestrial altitude associated with cognitive function decrement and mood states changes,such impairment in aviators could be a safety hazard.For this reason the aim of this study was to evaluate the changes of profiles of mood states of 18 healthy volunteers after exposed to different altitude(300 m,2800 m,3600 m and 4400 m) of hypoxia for 1 h in order to cope with the actual problems of the southwest airline.
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The results of this experiment suggested that the negative mood factor (T,F,C) points increased progressively and the positive mood (V)points decreased gradually during the hypoxia exposure for 1 h,and the scores of S-AI had a similar tendency to POMS.It indicated that mild and moderate hypoxia may have a negative effect on mood state.However,no general change was found in the points of D,A despite the fact that hypoxia was equivalent to an altitude of 4400 m.This may be partially because the subjects know much about this experiment and cooperated sincerely and partially by the reason of competition in the process with others.The time course of POMS exposure to 2800 m showed that the negative factor point(T) and S-AI scores increased at the beginning of the exposure,it suggested that the subjects may be nervous in a new environment and worried about what the altitude would be.Yet the V points had a tendency to increased at the beginning of exposure then dropped down toward the end of the exposure,it suggested that hypoxia especially mild hypoxia as a stress may produce some temporary positive effects on cognitive and mood state,but it can't maintain till the end of exposure.
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About the problem of threshold of hypoxia,JIA SiGuang et al,suggested that during exposure to hypoxic environment,guarantee range of performance was 3000 m,and the permitted range was 4000 m.Based on this suggestion,they established corresponding physiological protection criteria[8].Foweler etc pointed out that the threshold of maintaining normal performance was 9750 ft(2972 m)[4].Shukitt and Banderet reported significant reduction in unhappiness after ascending to a mountaintop laboratory at 4300 m,while aggressiveness was unchanged or reduced[12].The overall data from this experiment indicated there were negative effects on mood state even exposure to 2800 m for 1 h,These effects were further aggravated under exposure to 3600 m or 4400 m,this is quite similar to Green RG and Morgan DR's reports who found that when oxygen concentration was lowered to 13%(equivalent to 3400 m) at normal air pressure,adverse effects on human cognition,efficiency and mood may be brought about[10].The relationship between mood state and cognitive should be further assessed.Complementary studies and a larger sample of subjects should be involved in further experiments in order to get more information.
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[3]SHU Liang.Questionnaires of state anxiety inventory[J].Chinese Journal of Psychohygien,1993,(suppl):205～207
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舒 良.状态-特质焦虑问卷.见：心理卫生评定量表手册，中国心理卫生杂志，1993,增刊，205～207
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吴兴裕，李学义，韩厉萍等.急性中度缺氧对人计算能力影响的研究(英文)[J].航天医学与医学工程,1998,11(6):391～395
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[9]Green RG,Morgan DR.The effects of mild hypoxia on a logical reasoning task[J].Aviation space and Environ mantal Medicine,1985,56:1004～8
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Recieved date:1999-03-15, 百拇医药