研究者表明，这是由于我们的自然睡眠-觉醒周期或者昼夜节律的影响。

This could be due to the effects of our natural sleep-wake cycle, or circadian rhythm, the researchers suggest.

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控制我们24小时睡眠和清醒生理周期的自然生物钟，生理的节奏很容易会被改变的时间表扰乱，他们深受光线和黑暗的影响。

The natural internal clock that controls our 24-hour cycle of sleep and waking, circadian rhythms are easily upset by changes in schedule, and they're greatly affected by light and darkness.

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