Fast Track articlePreliminary observations on the effects of sleep time in a sleep restriction paradigm
Introduction
Sleep restriction is common in the lives of many people. Different surveys have shown that, from school-aged children to professionals, people restrict their total sleep time to perform chores and/or engage in social, professional or familial activities. A cumulative reduction in the normal nightly sleep period results in decrements in daytime function and quality of life [1].
There is a range of responses to experimentally reduced total sleep time. Powell et al. [2], using a road circuit with signal lights, road construction and a single-lane segment, studied the effect of 7 days of sleep restriction to 4 h per night on driving performance. Subjects were also evaluated on their ability to avoid a ball rolled in front of the car and to slalom between cones. The results were variable, from very significant decrements in performance to the point of a complete inability to drive, to no change compared to baseline. Philip et al. [3], who had the same subjects drive 600 miles on a highway before and immediately after one night of sleep deprivation, had similar findings. There are individual differences in the impact of sleep restriction/deprivation on driving performance.
Many factors may contribute to these differences. Our protocol was aimed at addressing the following question: Does the time of sleep during the night in a sleep restriction paradigm impact the next day's behavior? As our protocol was complex, we will only present a subset of findings on the effect of sleep restriction to 4 h per night for 7 days on nocturnal sleep architecture, Maintenance of Wakefulness test (MWT) [4], breathing during sleep and serum leptin levels compared to baseline [5], [6], [7], [8]. The presentation will more specifically address the following questions: Does the placement of sleep lead to different changes in the percentage of slow wave sleep and rapid eye movement (REM) sleep during the restriction period? Our hypothesis was that it would. Do the expected changes in MWT scores relate to the placement of the nocturnal sleep? Our hypothesis was that it would not, with sleep restriction being the leading factor in the MWT findings. Does sleep restriction lead to the appearance of snoring? Our hypothesis was that it would not in these normal young individuals with normal weight and cranio-facial anatomy. Would the sleep restriction have an impact on the serum leptin level? Our hypothesis was that it would, with an increase in serum leptin associated with an increase in food intake.
Section snippets
Protocol
Young male adults from a university were recruited by word of mouth and from advertisements to participate in a 12-day experiment during the summer. Payments to the subjects were based on the number of days of participation, with a maximum of $1000 for completing the study. All subjects had a normal physical evaluation at entry, including a urine test for medication and drug intake. They had overall sleep times within a normal range, and Epworth Sleepiness [9] and Horne and Osberg questionnaire
Results
All subjects completed the protocol. No mood changes occurred during the experiment, as was indicated by a daily visit by a psychiatrist as mandated by the Institutional Review Board (IRB). Of the eight young men, seven were between 18 and 20 years of age and in vacation between high school and college, and the other was 25 years old, out of college and temporarily unemployed. Subjects were randomized to Groups A and B at entry. All of the subjects had normal clinical evaluation, including a
Discussion
Sleep restriction is common in the general population. It may be caused by external conditions or self-inflicted, and varies in degree.
Our experiment on young male subjects produced several findings, some unexpected; many of our ‘a priori’ hypotheses were not confirmed. We hypothesized that the group assigned to bed at 02:30 h would have more REM sleep than the group which slept earlier in the night. This hypothesis was not clearly supported in this preliminary study. Overall, there was always
Acknowledgements
This work was supported by the Sleep Education and Research Foundation of Palo Alto.
References (18)
- et al.
Maintenance of Wakefulness Test: a polysomnographic technique for evaluating treatment in patients
Electroencephalogr Clin Neurophysiol
(1982) Leptin, obesity, and obstructive sleep apnea
Chest
(2000)- et al.
Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4–5 h of sleep per night
Sleep
(1997) - et al.
The road to danger: the comparative risks of driving while sleepy
Laryngoscope
(2001) - et al.
Fatigue, sleep restriction and driving performances [abstract]
Sleep
(2003) - et al.
Collection and interpretation of plasma leptin concentration data in humans
Obes Res
(1999) - et al.
Leptin and the regulation of body weight in mammals
Nature
(1998) - et al.
Leptin prevents respiratory depression in obesity
Am J Respir Crit Care Med
(1999) A new method for measuring daytime sleepiness: the Epworth sleepiness scale
Sleep
(1991)
Cited by (78)
Impact of Sleep Restriction on Food Intake and Food Choice
2020, Neurological Modulation of Sleep: Mechanisms and Function of Sleep HealthSleep influences on obesity, insulin resistance, and risk of type 2 diabetes
2018, Metabolism: Clinical and ExperimentalThe neurocognitive consequences of sleep restriction: A meta-analytic review
2017, Neuroscience and Biobehavioral ReviewsThe effects of partial sleep restriction and altered sleep timing on appetite and food reward
2017, AppetiteCitation Excerpt :Therefore, the use of a within-subject design to assess the influence of sleep timing when imposing a sleep restriction period on measures of appetite and food reward is novel. Previous studies have reported reductions in REM sleep duration (Tilley & Wilkinson, 1984; Wu et al., 2010) and sleep efficiency (Guilleminault et al., 2003) when sleep was restricted to the first vs. second half of the night, which corroborate our findings. Although differences in REM sleep duration were not associated with changes in appetite and food reward ratings between the control and advanced wake-time conditions, decreases in REM sleep duration were associated with increases in post-breakfast hunger AUC between both sleep restriction conditions.
Associations between sleep duration and abnormal serum lipid levels: data from the Korean National Health and Nutrition Examination Survey (KNHANES)
2016, Sleep MedicineCitation Excerpt :A longitudinal study over a 10-year period in the USA also found that actigraphy-assessed longer sleep duration was associated with high TC and LDL-C levels [8]. There is much evidence on the mechanisms that may explain a link between sleep deprivation and poor lipid profiles [20–22]. Mechanisms such as a decrease in the blood concentration of leptin or an increase in the blood concentration of ghrelin owing to sleep restriction may be involved in the biological mechanisms responsible for the associations between shorter sleep duration and abnormal serum lipid levels.
Does more sleep matter? Differential effects of NREM- and REM-dominant sleep on sleepiness and vigilance
2015, Neurophysiologie Clinique