de Haan Stella, Dourte Marine, Deantoni Michele, Reyt Mathilde, Baillet Marion, Berthomier Christian, Muto Vincenzo, Hammad Gregory, Cajochen Christian, Reichert Carolin F, Maire Micheline, Schmidt Christina, Postnova Svetlana
Sleep and Chronobiology Laboratory, GIGA-CRC Human Imaging, University of Liège, 4000 Liège, Belgium.
Psychology and Neurosciences of Cognition Research Unit (PsyNCog), Faculty of Psychology and Educational Sciences, University of Liège, 4000 Liège, Belgium.
Clocks Sleep. 2025 Jan 2;7(1):2. doi: 10.3390/clockssleep7010002.
Fixed sleep schedules with an 8 h time in bed (TIB) are used to ensure participants are well-rested before laboratory studies. However, such schedules may lead to cumulative excess wakefulness in young individuals. Effects on older individuals are unknown. We combine modelling and experimental data to quantify the effects of sleep debt on sleep propensity in healthy younger and older participants. A model of arousal dynamics was fitted to sleep data from 22 young (20-31 y.o.) and 26 older (61-82 y.o.) individuals (25 male) undertaking 10 short sleep-wake cycles during a 40 h napping protocol, following >1 week of fixed 8 h TIB schedules. Homeostatic sleep drive at the study start was varied systematically to identify best fits between observed and predicted sleep profiles for individuals and group averages. Daytime sleep duration was the same on the two days of the protocol within the groups but different between the groups (young: 3.14 ± 0.98 h vs. 3.06 ± 0.75 h, older: 2.60 ± 0.98 h vs. 2.37 ± 0.64 h). The model predicted an initial homeostatic drive of 11.2 ± 3.5% (young) and 10.1 ± 3.5% (older) above well-rested. Individual variability in first-day, but not second-day, sleep patterns was explained by the differences in the initial homeostatic drive for both age groups. Our study suggests that both younger and older participants arrive at the laboratory with cumulative sleep debt, despite 8 h TiB schedules, which dissipates after the first four sleep opportunities on the protocol. This has implications for protocol design and the interpretation of laboratory studies.
固定的睡眠时间表，卧床时间为8小时（TIB），用于确保参与者在实验室研究前得到充分休息。然而，这样的时间表可能会导致年轻人累积过多的清醒时间。对老年人的影响尚不清楚。我们结合建模和实验数据，以量化睡眠债对健康的年轻和老年参与者睡眠倾向的影响。对22名年轻人（20 - 31岁）和26名老年人（61 - 82岁）（25名男性）在40小时小睡方案中进行10个短睡眠 - 清醒周期的睡眠数据拟合了一个唤醒动力学模型，该方案遵循>1周的固定8小时TIB时间表。在研究开始时系统地改变稳态睡眠驱动力，以确定个体和组平均值的观察到的和预测的睡眠概况之间的最佳拟合。在方案的两天内，各年龄组的日间睡眠时间相同，但不同年龄组之间存在差异（年轻人：3.14±0.98小时对3.06±0.75小时，老年人：2.60±0.98小时对2.37±0.64小时）。该模型预测，与充分休息相比，年轻人的初始稳态驱动力为11.2±3.5%，老年人为10.1±3.5%。两个年龄组第一天而非第二天睡眠模式的个体差异可以通过初始稳态驱动力的差异来解释。我们的研究表明，尽管有8小时的TIB时间表，年轻和老年参与者到达实验室时都有累积的睡眠债，这种睡眠债在方案的前四个睡眠机会后会消散。这对方案设计和实验室研究的解释有影响。
