Risk for adverse cardiovascular events increases when blood pressure does not decrease at night (“non-dipping,” <10% decrease from daytime blood pressure). Shiftwork alters relationships between behaviors and endogenous circadian rhythms (i.e., circadian disruption along with variable sleep timing), and chronic shiftwork increases cardiovascular disease risk. To determine whether transitioning into shiftwork changes the overnight blood pressure dipping pattern, we leveraged a natural experiment that occurs when newly-hired bus operators transition from a daytime training schedule into an early-morning shiftwork or daywork schedule. Twenty participants were studied in a 90-day protocol upon new employment and underwent cardio-metabolic health assessments, including ambulatory blood pressure monitoring, and weekly sleep-wake diaries. Measurements were repeated after ~30 and 90 days after transitioning to a day or an early-morning shiftwork schedule. Newly-hired shiftworkers displayed dramatic changes in overnight blood pressure, with 62% converting from a healthy dipping blood pressure to the nondipping pattern, resulting in 93% of shiftworkers displaying a nondipping phenotype at 90-days. In contrast, 50% of dayworkers had a nondipping profile at baseline and this decreased to 0% at 90-days, a significant difference from shiftworkers (p = .001). At 90-days, overnight blood pressure dipping was ~7% less in shiftworkers than dayworkers (–6.3% [95%CI –3.7 to –8.8%] vs –13.1% [–10.3 to –15.9%]: p < .01), with changes in dipping associated with changes in sleep timing variability (r2 = .28, p = .03). The observed changes in overnight blood pressure dipping in newly-hired early-morning shiftworkers, which were associated with sleep timing variability, may be an early warning sign of increased cardiovascular risk among shiftworkers.

中文翻译：

---

过渡到清晨轮班工作后，夜间血压的快速变化

当夜间血压没有下降（“非下降”，<10% 比白天血压下降）时，心血管不良事件的风险会增加。轮班工作改变了行为和内源性昼夜节律之间的关系（即昼夜节律紊乱以及可变的睡眠时间），而长期轮班工作会增加心血管疾病的风险。为了确定过渡到轮班工作是否会改变夜间血压下降模式，我们利用了一个自然实验，该实验发生在新雇用的巴士操作员从白天培训计划过渡到清晨轮班工作或白天工作计划时。20 名参与者在新工作后接受了为期 90 天的研究，并接受了心脏代谢健康评估，包括动态血压监测和每周睡眠-觉醒日记。在过渡到一天或清晨轮班工作后约 30 天和 90 天后重复测量。新雇用的轮班工人夜间血压发生了巨大变化，62% 的轮班工人从健康的下降血压转变为非下降模式，导致 93% 的轮班工人在 90 天时表现出非下降表型。相比之下，50% 的日工在基线时具有非浸渍特征，并且在 90 天时降至 0%，与轮班工有显着差异 (p = .001)。在 90 天时，轮班工人的夜间血压下降比日工低约 7%（–6.3% [95%CI –3.7 至 –8.8%] 与 –13.1% [–10.3 至 –15.9%]：p < . 01），与睡眠时间变异性变化相关的倾角变化（r2 = .28，p = .03）。