Sleep apnea is a common sleep disorder characterized by periodic breathing cessation and intermittent hypoxia (IH). While previous studies have demonstrated that IH alone can influence metabolic outcomes such as body weight, it remains unclear how the timing of IH can specifically affect these outcomes. Here, we examine how pairing 10-hour periods of IH to either the animals' resting phase (e.g. IH during the day) or active phase (e.g. IH during the night) differentially affects body weight, macronutrient selection, energy expenditure, respiratory exchange rate, and glucose tolerance. We find that in contrast to mice exposed to IH during the night, mice exposed to IH during the day preferentially decrease their carbohydrate intake and switch to fat metabolism. Moreover when the IH stimulus was removed, mice that had been exposed to day IH continued to eat a minimal amount of carbohydrates and consumed a higher percentage of Kcal from fat for at least 5 days. These data demonstrate that food choice and substrate utilization are secondary to the timing of IH but not IH itself. Taken together, these data have key clinical implications for individuals with sleep apnea and particularly those who are also experiencing circadian disruption such as night-shift workers.

中文翻译：

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间歇性缺氧的时间不同地影响小鼠的常量营养素摄入和能量底物利用。

睡眠呼吸暂停是一种常见的睡眠障碍，其特征是周期性呼吸停止和间歇性缺氧 (IH)。虽然之前的研究表明单独 IH 可以影响代谢结果，如体重，但尚不清楚 IH 的时间如何具体影响这些结果。在这里，我们研究了将 10 小时的 IH 与动物的休息期（例如白天的 IH）或活跃期（例如夜间的 IH）配对如何对体重、常量营养素选择、能量消耗、呼吸交换率产生不同的影响，和葡萄糖耐量。我们发现，与夜间暴露于 IH 的小鼠相比，白天暴露于 IH 的小鼠会优先减少碳水化合物的摄入量并转而进行脂肪代谢。此外，当去除 IH 刺激时，暴露于 IH 日的小鼠继续吃最少量的碳水化合物，并从脂肪中消耗更高比例的千卡热量至少 5 天。这些数据表明，食物选择和底物利用次要于 IH 的时间，而不是 IH 本身。综上所述，这些数据对睡眠呼吸暂停患者，尤其是那些也经历昼夜节律紊乱的人（如夜班工人）具有关键的临床意义。