Blacks (African Americans) have shorter free-running circadian periods than whites (Caucasian Americans).
Blacks (African Americans) have shorter free-running circadian periods than whites (Caucasian Americans).
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DOI：
10.3109/07420528.2012.700670
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发表时间：
2012-10
影响因子：
2.8
通讯作者：
Smith MR
中科院分区：
文献类型：
--
作者：
Eastman CI;Molina TA;Dziepak ME;Smith MR
自由运行期（τ）的长度影响动物在LD循环相移后如何重新牵引。周期较短的个体比周期较长的个体更快地适应相位提前，而周期较长的个体比周期较短的个体更快地适应相位延迟。以时间隔离单位和强制去同步方案（其中将日长设定为超出夹带范围）测量的人类自由活动期的范围为约23.5至26小时，这取决于个体和实验条件（例如，时间隔离与强制去同步）。我们研究了94名受试者通过ultradian LD循环自由跑步，这是一种强迫的不同步，日长为4小时（2.5小时在昏暗的灯光下醒来，~ 35勒克斯，交替1.5小时在黑暗中睡眠）。在超日LD周期的三个24小时之前（基线）和之后（最后）进行昼夜节律相位评估。在这些评估期间，每30分钟收集唾液样品，随后分析褪黑激素。暗光褪黑激素起始（DLMO）从基线到最终相位评估的相移给出了自由运行期。平均± SD时间为24.31 ± .23 h，范围为23.7 - 24.9 h。黑人受试者的自由奔跑时间显著短于白人（24.18 ± .23 h，N=20 vs. 24.37 ± .22 h，N=55）。在我们的黑人样本中，女性的比例高于男性，因此为了检查τ的差异，我们将黑人女性与白色女性进行了比较。同样，黑人受试者的自由奔跑时间显著更短（24.18 ± .23，N=17 vs. 24.41 ± .23，N=23）。我们没有发现任何性别差异的自由运行期间。这些发现产生了几个可检验的预测：平均而言，黑人应该比白人更快地适应跨越时区的向东飞行，而白人应该比黑人更快地适应向西飞行。此外，黑人应该有更多的困难，以适应夜班工作和白天睡眠，这需要一个相位延迟。另一方面，白人更有可能难以适应社会强加的早期工作和学校时间表。需要更多的研究来证实这些结果和预测。
The length of the free-running period (τ) affects how an animal re-entrains after phase shifts of the LD cycle. Those with shorter periods adapt faster to phase advances than those with longer periods, while those with longer periods adapt faster to phase delays than those with shorter periods. The free-running period of humans, measured in temporal isolation units and in forced desychrony protocols in which the day length is set beyond the range of entrainment, ranges from about 23.5 to 26 hours, depending on the individual and the experimental conditions (e.g., temporal isolation vs. forced desychrony). We studied 94 subjects free-running through an ultradian LD cycle, which was a forced desychrony with a day length of 4 h (2.5 h awake in dim light, ~ 35 lux, alternating with 1.5 h for sleep in darkness). Circadian phase assessments were conducted before (baseline) and after (final) three 24-h days of the ultradian LD cycle. During these assessments, saliva samples were collected every 30 min and subsequently analyzed for melatonin. The phase shift of the dim light melatonin onset (DLMO) from the baseline to the final phase assessment gave the free-running period. The mean ± SD period was 24.31 ± .23 h and ranged from 23.7 to 24.9 h. Black subjects had a significantly shorter free-running period than Whites (24.18 ± .23 h, N=20 vs. 24.37 ± .22 h, N=55). We had a greater proportion of women than men in our Black sample, so to check the τ difference we compared the Black women to the White women. Again, Black subjects had a significantly shorter free-running period (24.18 ± .23, N=17 vs. 24.41 ± .23, N=23). We did not find any sex differences in the free-running period. These findings give rise to several testable predictions: on average, Blacks should adapt quicker to eastward flights across time zones than Whites, whereas Whites should adjust quicker to westward flights than Blacks. Also, Blacks should have more difficulty adjusting to night shift work and day sleep, which requires a phase delay. On the other hand, Whites should be more likely to have trouble adapting to the early work and school schedules imposed by society. More research is needed to confirm these results and predictions.
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影响因子：
5.5
作者：
MILLS, JN
通讯作者：
MILLS, JN
DOI：
10.1073/pnas.1010666108
发表时间：
2011-09-13
影响因子：
11.1
作者：
Duffy, Jeanne F.;Cain, Sean W.;Czeisler, Charles A.
通讯作者：
Czeisler, Charles A.
影响因子：
2.9
作者：
EDGAR, DM;KILDUFF, TS;DEMENT, WC
通讯作者：
DEMENT, WC
DOI：
10.2170/jjphysiol.49.425
发表时间：
1999-10-01
期刊：
JAPANESE JOURNAL OF PHYSIOLOGY
影响因子：
--
作者：
Endo, T;Honma, S;Honma, K
通讯作者：
Honma, K
影响因子：
4.4
作者：
Hiddinga, AE;Beersma, DGM;VandenHoofdakker, RH
通讯作者：
VandenHoofdakker, RH