労働科学のバックナンバー
2008/11/10発売号 (84巻4号)
労働科学

出版社：労働科学研究所
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■労働科学の目次

久保智英，佐々木司，松元俊
ノルマによる心理的ストレスが連続睡眠短縮夜とその後の回復夜の睡眠構築に及ぼす影響
労働科学，84(4), 119～128，(2008)

本研究は，課題にノルマを与えた際の心理的ストレスが10日間の連続睡眠短縮夜とその後4日間の
回復夜の睡眠構築に与える影響を検討した。
課題を達成した群（達成群）と達成できなかった群（非達成群）に分けて比較した結果，
睡眠効率，SWS，S2，%SWS，S2には条件間に有意差は
検出されなかったが，REM潜時とREMS（分），%REMSに有意差がみられた。またSOREMpも非達成群に多く観察された。
とりわけ，非達成群のREM潜時は睡眠短縮夜を終えても，もとの水準に回復しなかった。
本研究より，ノルマによる心理的ストレスの影響は
REM睡眠変数に影響する事が示唆された。（図５，表２）（自抄）
キーワード：心理的ストレス；過労死；REM睡眠；連続睡眠短縮；ノルマ

Tomohide KUBO，Tsukasa SASAKI，Shun MATSUMOTO
Impact of Psychological Stress Due to Assigned Task on Sleep Architecture Under the Condition of Repeated
Sleep Restriction and Subsequent Recovery
THE JOURNAL OF SCIENCE OF LABOUR，84(4), 119～128，(2008)

The purpose of this study was to examine the impact of psychological stress on sleep architecture under the
condition of sleep restriction with assigned tasks and subsequent restoration periods. Male participants
(N=16; mean age; 27.3, range; 19 - 38) were required to attend a laboratory for sixteen consecutive nights for
recording their performance under the following conditions: adaptation night (A; 23：00-7:00), baseline night (B; 23：00-7:00),
sleep restriction night 1-10 (SR1-SR10; 01：00-6:00) and recovery night 1-4 (R1-R4; 23：00-7:00).
The data of four participants were, however, excluded from the analysis because of technical failures.
To expose the participants to psychological stress due to assigned tasks, they were required to complete English
transcription tasks by SR10. We informed the participants we would not pay compensation (255,000 yen) at all if
they could not complete the assigned tasks in time. Therefore, the psychological stress in this study was mainly
due to the factors of assigned tasks. However, we paid the compensation regardless of their achievement at the
end of the experiment. sleep architecture was evaluated by sleep efficiency, %S2, %SWS, %REM sleep and REM sleep latency.
To reveal the impact of the psychological stress on sleep architecture, we classified all variables into the completed
group (N=6) and the non-completed group (N=6), according to the achievement of the tasks.
Most characteristic findings in this study were the variables of REM sleep. To sum up, we observed shorter
REM sleep latency and greater REM sleep (in minutes), %REM sleep in the non-completed group compared with
the Completed group (REM sleep latency; F1,10=5.957, p=0.035, REM sleep; F1,10=7.736, p=0.019, %REM sleep;
F1,10=13.054, p=0.005, respectively). It should be noted that participants in the non-completed group had difficulty
in recovering from the impact of psychological stress, and had not recovered by the fourth night of recovery sleep.
In summary, the results suggested that psychological stress in this study had an impact on the expression of REM sleep.
Key words：Psychological stress； Karoshi (Death due to over-fatigue)； Rapid eye movement sleep； Repeated sleep
restriction； Assigned task

木村康寛, 和久直樹, 高島充, 大川井宏明
座位継続時における居眠りと空気動圧センサーによる体動波の出現周期･活動量の関連
労働科学，84(4), 129～139，(2008)

現在，車や電車の居眠り運転が社会問題となっており，居眠り運転は重大な事故を引き起こす。そこで本研究は，
座位における居眠りと活動様態の関連に注目し，座面空気動圧センサー(エム・アイ・ラボ)による無拘束・無装着の
生体計測手法を用いて，座位継続中に生じる体動波様態の推移を調査した。
その結果，居眠りをした場合には，移動RMS値が初期値の10～30％に低下した。この低下は居眠り時前も居眠り時にも現われた。
これに対して，「居眠りなし」の例では25％以上を維持した。（図６，表１）（自抄）
キーワ－ド：居眠り予兆；空気動圧センサー；無拘束計測；体動波；座位

Evaluation of the Dozing-off Level During Prolonged Sitting by Means of Quantitative Measurement of Body Motion
and its Periodicity Using a Dynamic Air Pressure Sensor
Yasuhiro KIMURA , Naoki WAKU, Mitｓuru TAKASHIMA, Hiroaki OKAWAI
THE JOURNAL OF SCIENCE OF LABOUR，84(4), 129～139，(2008)

Recently, the drowsy state leading to dozing off driving during car driving has been a social problem because of a traffic
accidents induced. In the present study, we investigated body motion wave (BMW) changes during 90-minute sitting by
using a non-restraint, non-attachment measurement system with a dynamic air pressure sensor. As a result, in dozing
case, it was found that the moving root mean square value of the body motion wave decreased by 10-30 percent with
reference to that of the baseline level. Such decrease appeared in both before and during drowse/dozing off.
On the other hand, the above value in non-dozing case kept greater than 25 percent.
Key words：Prediction of Dozing off ；Dynamic air pressure sensor；Non-restraint measurement；Body motion wave(BMW)；Sitting position

福田宇志
踏切における歩行者・自転車利用者のリスクテイキング行動―警報時間の影響―
労働科学，84(4), 140～150，(2008)

リスクテイキング行動を生じさせる警報時間の影響を明らかにしようとした。降りきった遮断機をくぐって渡り始めた
歩行者・自転車利用者は２名見られたが，踏切の直前に着くやいなや降りきった遮断機をくぐって渡り始めていた。
警報が鳴り始めてから遮断機が降り始めるまでの期間の歩行者・自転車利用者の横断実行率は90％以上(90.5～100％)と
非常に高かったが，遮断機が降り始めてから遮断機が降りきるまでの期間では4.7～36.8％低い，63.2～90.0％であった。
遮断動作後の横断実行率を合計警報時間が長い朝時間帯と短い昼時間帯で比較すると，朝時間帯のほうが
6.0～14.6％横断実行率が高かった。
また，朝時間帯においては，通勤・通学途中の歩行者・自転車利用者が多かったことが示唆されており，これらの結果は，
警報時間や利用場面に起因する時間的なデメリットはリスクテイキング行動の動機となるという予想と一致していた。
（図７，表１）（自抄）
キーワード：踏切警報時間の影響；リスクテイキング行動；歩行者・自転車利用者；利用場面；時間的なデメリット

Takayuki FUKUDA
Risk-Taking Behaviour of Pedestrians and Cyclistsat Railroad Crossings―The Effects of Warning Time―
THE JOURNAL OF SCIENCE OF LABOUR，84(4), 140～150，(2008)

The effects of warning time on risk-taking behaviour of pedestrians and cyclists at rail crossings were examined.
A total of 457 pedestrians and cyclists were observed at three railroad crossings. One pedestrian and one cyclist
started to cross the rails after the rail gates were already closed. Both of them had just arrived within one meter
of the railroad crossings when they started to cross rails going around the closed gates. We considered that to
restrain such people from crossing dangerously, devices clearly showing the approaching degree of a train should
be installed. The rates of pedestrians and cyclists, who started to cross the rails after the bells started to ring but
before the gates were already closed, were compared between the morning home when there was a long warning
time and the daytime hours when the warning time was short. Over 90% of pedestrians and cyclists started to cross
the rails before the gates started to close.
These ratios decreased to 63.2–90.0% after the gates started to close. The rates of those crossing after the
gates started to close during the morning hours were higher than those during the daytime hours: 6.0–14.6%.
In the morning, if people would not started to cross the rails after the warning, they would have to wait for a long
time until the gates were opened again, and they would then have to hurry on to get to work or get to school on time.
Therefore, these results confirmed our expectation that time disadvantages caused by long warning times and their
circumstances of using rail crossings motivated risk-taking behaviour.
Key Words：The effects of warning time of railroad crossings；Risk-taking behaviour；Pedestrians and
cyclists；Circumstances of usage；Time disadvantages

永田久雄
第11次労働災害防止計画と数値目標の意義
労働科学，84(4), 151～157，(2008)

第11次労働災害防止5ヵ年計画に記載されている労働災害の死傷者数を減少させるための数値目標について検証した。
その結果，予測される死傷者数の減少率よりかなり高い数値目標となっていることを，過去の災害統計値から推計した。
計画内容を検証した結果，数値目標を達成する上で優先して実施すべき死傷者件数の多い
転倒災害について，具体的な道筋について言及していない。このことから，数値目標を達成するのが困難であることを指摘した。
労働災害防止計画に，数値目標を記載することは不可欠であり，5年間で1,000億円を超える労働安全衛生対策事業費の
運用にあたっても，数値目標といった物さしの導入を図り事業の評価などを行う必要性について論じた。
（図６）（自抄）
キーワード: 労働災害；労働災害防止計画；転倒；数値目標；高年齢労働者

Hisao NAGATA（Ph.D.）
The 11th Industrial Accident Prevention Plan and the Significance of Numerical Targets
THE JOURNAL OF SCIENCE OF LABOUR，84(4), 151～157，(2008)

The numerical targets to decrease occupational accidents within the 5 year-period described in the 11th Industrial
Accident Prevention Plan have been analyzed, using approximated curves. As a result of the analysis, the numerical
targets are significantly higher than the values predicted from the past occupational accident-statistics.
The contents of the plan have been reviewed, and there are no specified measures to prevent most frequently
occurring accidents, such as falls on the same level, which should be given priority in order to fulfill numerical targets.
It is suggested that the numerical targets are indispensable to assess the level of achievement of the Industrial Accident
Prevention Plan and the various expenditures of a huge budget for the Occupational Safety and Health Measures.
This budget exceeds 100 billion yen over the five-year duration of this plan, and should be reevaluated for the purpose
of attaining the stipulated numerical values.
Key Words: Industrial accident； Prevention plan； Fall； Numerical target； Elderly worker