Impact of sleep restriction on metabolic outcomes induced by overfeeding: a randomized controlled trial in healthy individuals.

Background: Overconsumption of energy-dense foods and sleep restriction are both associated with the development of metabolic and cardiovascular diseases, but their combined effects remain poorly evaluated. Objective: The aim of this study was to assess whether sleep restriction potentiates the effects of a short-term overfeeding on intrahepatocellular lipid (IHCL) concentrations and on glucose homeostasis. Design: Ten healthy subjects were exposed to a 6-d overfeeding period (130% daily energy needs, with 15% extra energy as sucrose and 15% as fat), with normal sleep (8 h sleep opportunity time) or sleep restriction (4 h sleep opportunity time), according to a randomized, crossover design. At baseline and after intervention, IHCL concentrations were measured by proton magnetic resonance spectroscopy, and a dual intravenous [6,6-2H2]-, oral 13C-labeled glucose tolerance test and a polysomnographic recording were performed. Results: Overfeeding significantly increased IHCL concentrations (Poverfeeding < 0.001; overfeeding + normal sleep: +53% ± 16%). During the oral glucose tolerance test, overfeeding significantly increased endogenous glucose production (Poverfeeding = 0.034) and the oxidation of 13C-labeled glucose load (Poverfeeding = 0.038). Sleep restriction significantly decreased total sleep time, and the duration of stages 1 and 2 and rapid eye movement sleep (all P < 0.001), whereas slow-wave sleep duration was preserved (Poverfeeding × sleep = 0.809). Compared with overfeeding, overfeeding + sleep restriction did not change IHCL concentrations (Poverfeeding × sleep = 0.541; +83% ± 33%), endogenous glucose production (Poverfeeding × sleep = 0.567), or exogenous glucose oxidation (Poverfeeding × sleep = 0.118). Sleep restriction did not significantly alter blood pressure, heart rate, or plasma cortisol concentrations (all Poverfeeding × sleep = NS). Conclusions: Six days of a high-sucrose, high-fat overfeeding diet significantly increased IHCL concentrations and increased endogenous glucose production, suggesting hepatic insulin resistance. These effects of overfeeding were not altered by sleep restriction. This trial was registered at clinicaltrials.gov as NCT02075723. Other study ID numbers: SleepDep 02/14.

Prevalence and Diagnostic Approach to Sleep Apnea in Hemodialysis Patients: A Population Study.

BACKGROUND: Previous observations found a high prevalence of obstructive sleep apnea (OSA) in the hemodialysis population, but the best diagnostic approach remains undefined. We assessed OSA prevalence and performance of available screening tools to propose a specific diagnostic algorithm. METHODS: 104 patients from 6 Swiss hemodialysis centers underwent polygraphy and completed 3 OSA screening scores: STOP-BANG, Berlin's Questionnaire, and Adjusted Neck Circumference. The OSA predictors were identified on a derivation population and used to develop the diagnostic algorithm, which was validated on an independent population. RESULTS: We found 56% OSA prevalence (AHI ≥ 15/h), which was largely underdiagnosed. Screening scores showed poor performance for OSA screening (ROC areas 0.538 [SE 0.093] to 0.655 [SE 0.083]). Age, neck circumference, and time on renal replacement therapy were the best predictors of OSA and were used to develop a screening algorithm, with higher discriminatory performance than classical screening tools (ROC area 0.831 [0.066]). CONCLUSIONS: Our study confirms the high OSA prevalence and highlights the low diagnosis rate of this treatable cardiovascular risk factor in the hemodialysis population. Considering the poor performance of OSA screening tools, we propose and validate a specific algorithm to identify hemodialysis patients at risk for OSA for whom further sleep investigations should be considered.

Oscillating Positive Airway Pressure Versus CPAP for the Treatment of Obstructive Sleep Apnea.

Although continuous positive airway pressure (CPAP) is the most effective therapy for obstructive sleep apnea (OSA), it is not always well tolerated by the patients. Previous physiological studies showed that pressure oscillations applied to the pharynx could activate upper airway muscles, but it is not clear whether these pressure oscillations could be tolerated during sleep in OSA patients. The aim of this study was to assess the tolerance of oscillating positive airway pressure (O-PAP) (a CPAP device delivering high-frequency pressure oscillations to the upper airway) compared to CPAP. Fourteen OSA patients currently on CPAP [age 59.9 ± 10.1 years old, BMI 34.8 ± 7.2 kg/m(2), initial apnea-hypopnea index (AHI): 58.7 ± 25.2 events/h] used O-PAP or CPAP on two consecutive nights under polysomnography, in a single-blind randomized crossover design to assess sleep quality. A subtherapeutic pressure (70% of the optimal titrated pressure) was applied in both conditions and the residual AHI with each technique was also compared. There was no difference in measured or perceived sleep quality between the two treatment modalities (sleep efficiency 90.0% versus 88.1%, p = 0.54). Despite the small sample, we also found a trend toward a decrease in residual respiratory events with O-PAP compared to CPAP (median AHI 14.3 versus 20.5/h, p = 0.194). The good tolerance of O-PAP and the positive trend toward a reduction in residual AHI should stimulate further research on the effects of O-PAP in OSA patients.

Obstructive Sleep Apnea Severity and Overnight Body Fluid Shift before and after Hemodialysis.

BACKGROUND AND OBJECTIVES: Obstructive sleep apnea is associated with significantly increased cardiovascular morbidity and mortality. Fluid overload may promote obstructive sleep apnea in patients with ESRD through an overnight fluid shift from the legs to the neck soft tissues. Body fluid shift and severity of obstructive sleep apnea before and after hemodialysis were compared in patients with ESRD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Seventeen patients with hemodialysis and moderate to severe obstructive sleep apnea were included. Polysomnographies were performed the night before and after hemodialysis to assess obstructive sleep apnea, and bioimpedance was used to measure fluid overload and leg fluid volume. RESULTS: The mean overnight rostral fluid shift was 1.27±0.41 L prehemodialysis; it correlated positively with fluid overload volume (r=0.39; P=0.02) and was significantly lower posthemodialysis (0.78±0.38 L; P<0.001). There was no significant difference in the mean obstructive apnea-hypopnea index before and after hemodialysis (46.8±22.0 versus 42.1±18.6 per hour; P=0.21), but obstructive apnea-hypopnea index was significantly lower posthemodialysis (-10.1±10.8 per hour) in the group of 12 patients, with a concomitant reduction of fluid overload compared with participants without change in fluid overload (obstructive apnea-hypopnea index +8.2±16.1 per hour; P<0.01). A lower fluid overload after hemodialysis was significantly correlated (r=0.49; P=0.04) with a lower obstructive apnea-hypopnea index. Fluid overload-assessed by bioimpedance-was the best predictor of the change in obstructive apnea-hypopnea index observed after hemodialysis (standardized r=-0.68; P=0.01) in multivariate regression analysis. CONCLUSIONS: Fluid overload influences overnight rostral fluid shift and obstructive sleep apnea severity in patients with ESRD undergoing intermittent hemodialysis. Although no benefit of hemodialysis on obstructive sleep apnea severity was observed in the whole group, the change in obstructive apnea-hypopnea index was significantly correlated with the change in fluid overload after hemodialysis. Moreover, the subgroup with lower fluid overload posthemodialysis showed a significantly lower obstructive sleep apnea severity, which provides a strong incentive to further study whether optimizing fluid status in patients with obstructive sleep apnea and ESRD will improve the obstructive apnea-hypopnea index.

Sleep microstructure around sleep onset differentiates major depressive insomnia from primary insomnia.

In the present study we investigate whether alterations of sleep propensity or of wake propensity are implicated in sleep initiation disturbances encountered in major depressive insomnia and in primary insomnia. For this purpose, the time course of electroencephalogram (EEG) power density during the period preceding sleep onset and during the first non-rapid eye movement (REM) period was examined in three age and gender matched groups of 10 women and 11 men (healthy controls, primary insomniacs and depressive insomniacs). In contrast to healthy controls and depressive insomniacs, patients with primary insomnia did not experience a gradual decrease of their alpha and beta1 power during the sleep onset period and had a lower delta activity in the 5 min preceding sleep onset. Compared with the two other groups, depressive patients exhibit less dynamic changes in slow wave activity during the first non-REM period. The present results suggest that hyperarousal (high 'Process W') may mainly be implicated in the sleep initiation difficulties of primary insomniacs whereas the homeostatic sleep regulation process seems to be partially maintained. In our major depressed patients, the sleep initiation disturbances appeared to relate to a lower sleep pressure (low 'Process S') rather than to hyperarousal. This study supports the idea that different mechanisms are implicated in sleep disturbances experienced by primary insomniacs and major depressive insomniacs.

Acute low single dose of apomorphine reduces periodic limb movements but has no significant effect on sleep arousals: a preliminary report.

STUDY OBJECTIVES: To investigate the effects of apomorphine on the frequency of periodic limb movements during sleep (PLMS) and on sleep architecture. DESIGN: Nine patients presenting PLMS (including eight patients with restless legs syndrome) underwent three consecutive night sleep recordings. They received a single dose of 0.5 mg subcutaneous apomorphine at bedtime the third night. RESULTS: When computing PLMS during four 2-h periods of sleep, a significant period by apomorphine-effect was demonstrated, with a marked reduction of PLMS during the first 4 h post-injection (P < 0.01). No significant differences were found in sleep macroarchitecture between the three recorded nights, excepted a slight reduction in sleep latency during the third night (P < 0.05). Despite the decreased number of PLMS after apomorphine injection, there were significant changes neither in the total number of arousals nor in the index of arousals per hour of sleep. CONCLUSION: Our results add further support to the dopaminergic hypothesis in the generation of PLMS. The persistence of arousals suggests that they are not simply the consequence of PLMS but a primary phenomenon, not related with the dopaminergic system.