| Project/Area Number |
02670231
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hygiene
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| Research Institution | Aichi Medical University |
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Principal Investigator |
WATANABE Takemasa (1991-1992) Aichi Medical University, Hygiene, Lecturer, 医学部, 講師 (50182928)
小林 章雄 (1990) 愛知医科大学, 医学部, 助教授 (80135342)
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| Co-Investigator(Kenkyū-buntansha) |
渡辺 文眞 愛知医科大学, 医学部, 助手 (50182928)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1990: ¥100,000 (Direct Cost: ¥100,000)
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| Keywords | Shift work / Circadian rhythm / Blood pressure / Middle aged worker / Reactivity / 反応性 / 循環機能 / 自律神経機能 / 交代制勤務 / 中高年齢者 |
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| Research Abstract |
We monitored blood pressure (BP) and heart rate (HR) every 15 minutes over 24 hours by a noninvasive ambulatory method in normotensive and hypertensive shift workers, once while on the day shift and once while on the night shift. The circadian variations in BP and HR were almost completely reversed with the switch from the day shift to the night shift in normotensive workers. In hypertensive workers, however, the circadian pattern was not completely reversed, i.e. BP and HR while on the night shift dropped to the lowest level of the day between 0000 and 0400. Thus, we found differences between normotensive and hypertensive workers in the effects of shift work and time of day on BP and HR.
In a laboratory condition, we compared reactivity of blood pressure to three stress loading tests (mental arithmetic, cold face test, and head-up tilt) which were measured three times a day at 0900, 2100 and 0300. Blood pressure significantly declined during head-up tilt at 0300 in the hypertensive subjects, while their cardiac output showed no change during the test. We speculated that some mechanisms such as increasing the peripheral vascular resistance might be impaired in the hypertensive subjects during midnight, which is also related to the drop of blood pressure level between 0000 and 0400 in the hypertensive shift workers.
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