Munir M. Sharif

Circadian pattern of sleep, energy expenditure, and body temperature of young healthy men during the intermittent fasting of Ramadan

We hypothesize that factors other than a sudden shift in eating habits contribute to delay of circadian rhythms during Ramadan. We assessed circadian changes during a baseline period (BL, 1 week before Ramadan), the first week (R1), and the second week (R2), of Ramadan, in six healthy Muslim young adults using portable armband physiological and activity sensor devices. All participants lived in an unconstrained environment and showed delayed sleep phase syndrome, so that they normally slept during the day and ate at night. During Ramadan, there was a further delay in the acrophase of skin temperature during Ramadan, indicating a shift in the circadian pattern of body temperature. Additionally, there was a delay in the peak of energy expenditure during R1 and R2. These results support our hypothesis that in addition to sudden shift in meal times, other factors may affect the sleep pattern and circadian rhythms during Ramadan.

The relationship between sleep and wake habits and academic performance in medical students: a cross-sectional study

BackgroundThe relationship between the sleep/wake habits and the academic performance of medical students is insufficiently addressed in the literature. This study aimed to assess the relationship between sleep habits and sleep duration with academic performance in medical students.MethodsThis study was conducted between December 2009 and January 2010 at the College of Medicine, King Saud University, and included a systematic random sample of healthy medical students in the first (L1), second (L2) and third (L3) academic levels. A self-administered questionnaire was distributed to assess demographics, sleep/wake schedule, sleep habits, and sleep duration. Daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). School performance was stratified as “excellent” (GPA ≥3.75/5) or “average” (GPA <3.75/5).ResultsThe final analysis included 410 students (males: 67%). One hundred fifteen students (28%) had “excellent” performance, and 295 students (72%) had “average” performance. The “average” group had a higher ESS score and a higher percentage of students who felt sleepy during class. In contrast, the “excellent” group had an earlier bedtime and increased TST during weekdays. Subjective feeling of obtaining sufficient sleep and non-smoking were the only independent predictors of “excellent” performance.ConclusionDecreased nocturnal sleep time, late bedtimes during weekdays and weekends and increased daytime sleepiness are negatively associated with academic performance in medical students.

Sleep estimation using BodyMedia's SenseWear™ armband in patients with obstructive sleep apnea

OBJECTIVES: We aimed to evaluate the validity of the BodyMedias SenseWear™ Armband (BSA) device in estimating total sleep time (TST) in patients with obstructive sleep apnea (OSA). METHODS: Simultaneous overnight recordings of in-laboratory polysomnography (PSG) and BSA were performed on (1) 107 OSA patients (mean age of 45.2 ± 14.3 years, mean apnea hypopnea index of 43 ± 35.7/hr and (2) 30 controls matched with OSA patients for age and body mass index. An agreement analysis between the PSG and BSA scoring results was performed using the Bland and Altman method. RESULTS: There was no significant difference in OSA patients between BSA and PSG with regard to TST, total wake time, and sleep efficiency. There was also no significant difference in the controls between BSA and PSG with regard to TST, total wake time, and sleep efficiency. Bland Altman plots showed strong agreement between TST, wake time, and sleep efficiency for both OSA and the controls. The intraclass correlation coefficients revealed perfect agreement between BSA and PSG in different levels of OSA severity and both genders. CONCLUSION: The current data suggest that BSA is a reliable method for determining sleep in patients with OSA when compared against the gold standard test (PSG). BSA can be a useful tool in determining sleep in patients with OSA and can be combined with portable sleep studies to determine TST.

Evaluation of the accuracy of manual and automatic scoring of a single airflow channel in patients with a high probability of obstructive sleep apnea.

Summary Background ApneaLink™ (AL) is a single-channel type-4 device that measures airflow. A limited number of studies have assessed AL’s usefulness in diagnosing obstructive sleep apnea (OSA) using automated scoring alone. This study was conducted to assess the sensitivity and specificity of AL in a selected group of people with clinical suspicion of OSA, using both automatic and manual scoring and comparing the results with those obtained for polysomnography (PSG). Material/Methods Simultaneous overnight recordings of in-laboratory PSG and AL were performed for 95 patients (mean age 46.3±12.6 yr) with a high clinical suspicion of OSA. PSG was scored manually according to the American Academy of Sleep Medicine (AASM) guidelines. AL data were analyzed automatically using a manufacturer-provided computerized algorithm. Manual scoring of the AL flow signal followed the AASM guidelines for reduction in flow. Results The mean apnea hypopneas index (AHI) for PSG was 34.1±32.4/hr. The AL Auto-AHI was 20.1±25.2/h, and the AL Manual-AHI was 39.5±30.4/h. The Pearson correlation coefficients were r=0.883 between PSG-AHI and AL Auto-AHI, and r=0.966 between PSG-AHI and AL Manual-AHI. At AHIs of 5, 10, 15, and 30, the AL Auto sensitivity/specificity was 0.79/0.68, 0.70/0.89, 0.64/0.94 and 0.63/0.98, and the AL Manual sensitivity/specificity was 1.00/0.43, 1.00/0.56, 0.98/0.58 and 1.00/0.80. Conclusions Combining auto and manual scoring of data (automatic scoring followed by manual scoring) recorded by single-channel ApneaLink™ provides good diagnostic agreement with conventional PSG recordings.

Intermittent fasting during Ramadan: does it affect sleep?

Islamic intermittent fasting is distinct from regular voluntary or experimental fasting. We hypothesised that if a regimen of a fixed sleep–wake schedule and a fixed caloric intake is followed during intermittent fasting, the effects of fasting on sleep architecture and daytime sleepiness will be minimal. Therefore, we designed this study to objectively assess the effects of Islamic intermittent fasting on sleep architecture and daytime sleepiness. Eight healthy volunteers reported to the Sleep Disorders Centre on five occasions for polysomnography and multiple sleep latency tests: (1) during adaptation; (2) 3 weeks before Ramadan, after having performed Islamic fasting for 1 week (baseline fasting); (3) 1 week before Ramadan (non‐fasting baseline); (4) 2 weeks into Ramadan (Ramadan); and (5) 2 weeks after Ramadan (non‐fasting; Recovery). Daytime sleepiness was assessed using the Epworth Sleepiness Scale and the multiple sleep latency test. The participants had a mean age of 26.6 ± 4.9 years, a body mass index of 23.7 ± 3.5 kg m−2 and an Epworth Sleepiness Scale score of 7.3 ± 2.7. There was no change in weight or the Epworth Sleepiness Scale in the four study periods. The rapid eye movement sleep percentage was significantly lower during fasting. There was no difference in sleep latency, non‐rapid eye movement sleep percentage, arousal index and sleep efficiency. The multiple sleep latency test analysis revealed no difference in the sleep latency between the ‘non‐fasting baseline’, ‘baseline fasting’, ‘Ramadan’ and ‘Recovery’ time points. Under conditions of a fixed sleep–wake schedule and a fixed caloric intake, Islamic intermittent fasting results in decreased rapid eye movement sleep with no impact on other sleep stages, the arousal index or daytime sleepiness.

Long-term follow-up of patients with narcolepsy-cataplexy treated with sodium oxybate (Xyrem).

Objectives:The clinical experience with sodium oxybate (Xyrem) in patients with narcolepsy-cataplexy is still limited, especially in children, elderly patients, and patients with concomitant obstructive sleep apnea (OSA). In this report, we describe 4 patients with narcolepsy and refractory cataplexy who were started on sodium oxybate and followed up for approximately 2 years, including an 11-year-old child and an elderly man with severe OSA. Methods:The sodium oxybate dose was built up gradually until symptoms were controlled, adverse effects appeared, or the maximum nightly dose of 9.0 g was reached. On average, each subject underwent 4 sleep studies during follow-up after starting sodium oxybate. The nightly dose needed to control symptoms ranged from 5.0 to 9.0 g. Results:Cataplexy, sleep paralysis, and sleep-onset hallucinations disappeared in all cases. In addition, daytime sleepiness decreased subjectively according to the Epworth Sleepiness Scale and objectively according to the Multiple Sleep Latency Test. Polysomnography demonstrated clear reductions in sleep latency, arousal index, and stage 1 sleep (N1). Slow-wave sleep (N3) and sleep efficiency increased with sodium oxybate treatment. Interestingly, the 11-year-old child and the elderly man with documented severe OSA on continuous positive airway pressure therapy demonstrated tolerability to sodium oxybate. Adverse effects included nausea, snoring, paresthesia, convulsion, and enuresis. However, all adverse effects disappeared after reduction of the dose. The beneficial effect of sodium oxybate persisted during the follow-up period. Conclusion:Sodium oxybate is an effective and well-tolerated medication for patients with refractory cataplexy. However, it requires special monitoring and follow-up by a specialized center. The improvement in clinical symptoms and sleep architecture seems to persist over time.

The prevalence of restless legs syndrome in adult Saudis attending primary health care.

OBJECTIVE This study assessed the prevalence and severity of restless leg syndrome (RLS) among patients attending primary health care (PHC) facilities. METHODS We interviewed 1303 consecutive patients attending PHC face-to-face using the International Restless Legs Syndrome Study Group (IRLSSG) criteria. We assessed the severity of RLS using the IRLSSG severity scale for RLS. RESULTS The prevalence of RLS in our sample was 5.2% and was highest among participants between 45 and 60 years of age. The overall prevalence was roughly equal between males and females; however, RLS was more prevalent in females older than 45 years compared to males in the same age group. Eight participants (11.8%) reported mild symptoms, 29 (42.6%) moderate, 29 (42.6%) severe, and 2 (2.9%) very severe. None of the participants had been diagnosed or treated for RLS. CONCLUSION Restless leg syndrome is common among Saudis (Arabs). Our study supports the findings of reports in other countries demonstrating that primary care physicians do not often recognize RLS.

Objective assessment of drowsiness and reaction time during intermittent Ramadan fasting in young men: a case-crossover study

BackgroundRamadan fasting and its attendant lifestyle changes induce changes in the circadian rhythm and in associated physiological and metabolic functions. Previous studies that have assessed psychomotor performance during Ramadan fasting have reported conflicting results. Therefore, we designed this study to objectively assess the effects of intermittent fasting during and outside Ramadan (to control for lifestyle changes) on drowsiness, blink total duration and mean reaction time (MRT) test while controlling for potential confounders.MethodsEight healthy volunteers with a mean age of 25.3 ± 2.9 years and a mean body mass index (BMI) of 23.4 ± 3.2 kg/m2 reported to the sleep laboratory on four occasions for polysomnography (PSG) and drowsiness and psychomotor assessments as follows: 1) adaptation; 2) 4 weeks before Ramadan while performing the Islamic fasting for 1 week (baseline fasting) (BLF); 3) 1 week before Ramadan (non-fasting baseline) (BL); and 4) during the second week of Ramadan while fasting (Ramadan). OPTALERT™ was used to objectively assess daytime drowsiness using the Johns Drowsiness Scale (JDS), and blink total duration and a visual reaction time test were used to assess MRT.ResultsRapid eye movement (REM) sleep percentage was significantly lower at BLF (17.7 ± 8.1%) and at Ramadan (18.6 ± 10.7%) compared with BL (25.6 ± 4.8%) (p < 0.05). There were no significant differences between JDS scores and blink total duration during the two test periods in BL, BLF and Ramadan. There were no significant changes in MRT during BL, BLF and Ramadan.ConclusionsUnder controlled conditions of fixed light/dark exposure, caloric intake, sleep/wake schedule and sleep quality, the Islamic intermittent fasting has no impact on drowsiness and vigilance as measured by the JDS, total blink duration and MRT.

Diurnal Intermittent Fasting during Ramadan: The Effects on Leptin and Ghrelin Levels

We aimed to assess the effect of Islamic intermittent fasting, during and outside of Ramadan, on plasma levels of leptin and ghrelin while controlling for several potential confounding variables. Eight healthy male volunteers with a mean age of 26.6±4.9 years reported to the sleep disorders center (SDC) at King Saud University on four occasions: 1) adaptation; 2) 4 weeks before Ramadan while performing Islamic fasting for 1 week (baseline fasting) (BLF); 3) 1 week before Ramadan (non-fasting baseline) (BL); and 4) during the second week of Ramadan while fasting. Plasma leptin and ghrelin levels were measured using enzyme-linked immunoassays at 22:00, 02:00, 04:00, 06:00, and 11:00. During BLF, there were significant reductions in plasma leptin concentrations at 22:00 and 02:00 compared with the baseline concentrations (at 22:00: 194.2±177.2 vs. 146.7±174.5; at 02:00: 203.8±189.5 vs. 168.1±178.1; p<0.05). During Ramadan, there was a significant reduction in plasma leptin levels at 22:00 (194.2±177.2 vs. 132.6±130.4, p<0.05). No significant difference in plasma ghrelin concentrations was detected during the BL, BLF, or Ramadan periods. Cosinor analyses of leptin and ghrelin plasma levels revealed no significant changes in the acrophases of the hormones during the three periods. The nocturnal reduction in plasma leptin levels during fasting may be the result of the changes in meal times during fasting.

Assessment of sleep patterns, energy expenditure and circadian rhythms of skin temperature in patients with acute coronary syndrome.

Summary Background There is no simple and practical way to monitor sleep patterns in patients in acute care units. We designed this study to assess sleep patterns, energy expenditure and circadian rhythms of patients’ skin temperature in the coronary care unit (CCU) utilizing a new portable device. Material/Methods The SenseWear Armband (SWA) was used to record sleep duration, distribution over 24 hr, energy expenditure and the circadian rhythms of skin temperature in 46 patients with acute coronary syndrome (ACS) for the first 24 hr in the CCU and upon transfer to the ward. An advanced analysis was used to extract and compare data associated with the above variables in the two settings. Results Patients in the CCU had a reduced night’s sleep duration (5.6±2.2 hr) with more frequent and significantly shorter night sessions (p=0.015) than patients in the ward. Energy expenditure and METs (metabolic equivalents of a task) were significantly lower in the CCU than in the ward. However, the midline-estimating statistic of rhythm (MESOR) and acrophase for skin temperature did not exhibit any significant difference between the two settings. Conclusions Patients with ACS have sleep fragmentation and shorter nocturnal sleep duration in the CCU compared to the ward. On the other hand, there was no difference in the circadian rhythms of skin temperature between patients in the CCU and the general wards.