Effects of sleep-wake pattern and residential status on psychological distress in university students

Sleep and Biological Rhythms - The effects of a delayed and/or disturbed sleep-wake pattern on mental functioning, frequently found in university students, were confirmed by several studies. The...     

Effects of essential oil inhalation on objective and subjective sleep quality in healthy university students

Aromatherapy with essential oils is one of the most popular complementary medical tools for improving sleep quality. However, only a few reports have objectively measured the effects of essential oils on sleep. Here, we used objective and subjective measures to analyze the effects of the essential oils of lavender (Lavandula angustifolia) and sweet orange (Citrus sinensis) on the sleep quality of healthy university students. The participants were monitored for 15 consecutive nights as they inhaled lavender oil and sweet orange oil, in a crossover design. Their sleep was monitored objectively by actigraphy, and total sleep time (TST), sleep efficiency, sleep latency, and wake after sleep onset (WASO) were analyzed. Their sleep was analyzed subjectively using Oguri–Shirakawa–Azumi (OSA) sleep inventory scores. Inhalation of an essential oil improved sleep measures only in participant whose sleep quality was poor in the control condition. Lavender seemed more effective than sweet orange in objective measures, especially in improving sleep latency. In the subjective sleep analysis, the essential oils improved sleep maintenance, dreaming, and sleep length in subjects who had poor sleep quality. Sweet orange seemed more effective than lavender in the subjective sleep measures. The difference between the two oils suggests that expectancy bias had little effect on the hypnotic effect of lavender on objective sleep. Although no obvious effect was observed in good sleepers, the inhalation of lavender oil could be effective for helping poor sleepers improve objective sleep quality.

     

Delayed sleep/wake rhythm and excessive daytime sleepiness correlate with decreased daytime brain activity during cognitive task in university students

Insufficient sleep and irregular sleep/wake rhythm are common problems among university students. We investigated the effect of sleep/wake rhythm and excessive daytime sleepiness (EDS) on the cortical oxygenation as measured by near-infrared spectroscopy (NIRS) and cognitive performance in university students. Peak- and integral values by a word fluency task were measured with NIRS. EDS was evaluated by the Epworth sleepiness scale (ESS), and performance function was evaluated using N-back task. Peak cerebral oxygenation was significantly correlated with ESS, bedtime, wake-up time, and median time of sleep. Accuracy on 2-back task was significantly correlated with integral value. Peak- and integral values were significantly lower, and bedtime and median time of sleep were significantly delayed in the EDS group than in the non-EDS group. EDS accompanied by delayed sleep/wake rhythm and short sleep duration may play an important role in decreasing daytime brain activity and cognitive performance.     

Prevalence of energy drink consumption and association with dietary habits among governmental university students in Riyadh

To determine the prevalence of Energy Drinks (ED) consumption, and the adverse effects experienced by consumers among governmental university students in Riyadh, and to assess the relationship between ED consumption and dietary habits. This is a cross-sectional study carried out in 2020 in a random sample of students at government universities in Riyadh (King Saud University (KSU) and Imam Muhammad Ibn Saud Islamic University (IMSIU). The study was conducted within a time frame of 3 months which included a total of 546 students. The data collection tool was an online self-administered questionnaire that included three sections. The first section addressed the characteristics of the students, the second section addressed ED consumption, and the third section addressed the dietary habits of ED consumers. A SPSS software-based analysis revealed that the percentage of ED consumers in our cohort was 29.3%. Moreover, we found a significant association between ED consumption and consumption of fewer than three meals, skipping breakfast, and fast food intake (χ² = 0.002, P = 0.364; χ² = 0.028, P = 0.341; and (χ² = 0.010, P = 0.369, respectively), with moderate correlation. No association was found between the consumption of EDs and that of fruits, vegetables, and snacks. Moreover, 36% of the consumers experienced jolt-and-crash symptoms and signs after ED consumption, with 84.5% of them exhibiting increased consumption of salty snacks, sweets, and fast food during the episodes. Our findings showed that ED consumption is not a common practice among governmental university students in Riyadh. Furthermore, the consumption of EDs was correlated with unhealthy dietary habits. Creating educational programs for school going students and providing healthy alternative options to the students is highly recommend. Future research should be conducted using a larger sample and including universities from the private sector, to compare the results.     

Effects of psychological stress on autonomic control of heart in rats.

The aim of this study was to examine the effects of psychological stress on autonomic control of the heart in rats. For this purpose, we evoked anxiety-like or fear-like states in rats by means of classical conditioning and examined changes in autonomic nervous activity using an implanted telemetry system and power spectral analysis of heart rate variability. Anxiety-like states resulted in a significant increase in heart rate (HR), low frequency (LF) power, and LF/HF ratio, with no change in high frequency (HF) power. Fear-like states resulted in a significant increase in HR and a significant decrease in HF power with no significant change in both LF power and LF/HF ratio, although LF/HF ratio increased slightly. These results suggest that autonomic balance becomes predominant in sympathetic nervous activity in both anxiety-like and fear-like states. These changes in rats correspond to changes which are relevant to cardiovascular diseases in humans under many kinds of psychological stress. Therefore, the experimental design of this study is a useful experimental model for investigating the effects of psychological stress on autonomic control of the heart in humans.     

Effects of olfactory stimuli on students with different tones of the autonomic nervous system

The effect of olfactory stimuli was determined on students (men and women) with different tones of the autonomic nervous system under moderate psychoemotional stress conditions (before an academic test). It was found that the direction of changes in the heart rate variability values of students after olfactory stimulation is determined by the initial tone of the autonomic nervous system. The conclusion was made that olfactory stimuli may be used for correcting psychoemotional stress in students more efficiently if the tone of the autonomic nervous system is taken into consideration.     

Effects of sleep deprivation on cognitive and physical performance in university students

Sleep and Biological Rhythms - Sleep deprivation is common among university students, and has been associated with poor academic performance and physical dysfunction. However, current literature...     

Effects of chloramphenicol on brain energy metabolism using 31P spectroscopy: influences on sleep-wake states in rat

Effects of chloramphenicol (antibiotic inhibiting complex-1 of respiratory chain) and thioamphenicol (TAP, a structural analog of CAP inactive on complex-1) were examined on cerebral energy metabolites and sleep-wake cycle architecture in rat. In the first group, animals were chronically equipped with a cranial surface resonator and ³¹P spectroscopic measurements were performed using a 2 T magnetic resonance spectrometer (operating frequency 34.46 MHz). CAP administration (400 mg/kg, tail vein, light period) induced deficits in phosphocreatine (−30%, p  < 0.01) and ATP (−40%, p  < 0.01), whereas TAP (400 mg/kg) had no effect. In the second group, animals were chronically implanted with polygraphic electrodes for EEG and electromyogram recordings. CAP administered intraperitoneally at light-onset reduced rapid-eye movement (REM) sleep (−60% in the first 6 h of light period, p  < 0.01), increased waking state (+65% in the first 6 h of light period, p  < 0.01), and slightly affected slow-wave sleep (SWS). During waking state, θ and σ power bands of the EEG were, respectively, increased and decreased ( p  < 0.05). During SWS, delta power band was reinforced ( p  < 0.05), while θ, α, and σ bands were decreased ( p  < 0.05). No changes occurred during REM sleep. TAP had no effect on sleep-wake states and spectral components of the EEG. Overall, these data indicate that REM sleep occurrence is linked to an aerobic production of ATP.     

Effects of polymodal rhythmic sensory influences on the human CNS state and autonomic functions

It was shown that polymodal rhythmic sensory influences (light, sound, vibratory-tactile), being a measure of neurocorrection, may be used for correction of the human psychophysiological state. The effectiveness of the method shows up in the positive influence on the mental sphere of a person, causing a decrease in the level of anxiety and improving the subjective well-being, and on the cognitive and autonomic functions. Polymodal rhythmic sensory influences are means of increasing the effectiveness of human intellectual activity, because it increases concentration in proportion to the increase in the parasympathetic activity induced by polymodal sensory stimuli.     

Effects of soccer matches on neutrophil and lymphocyte functions in female university soccer players

In this study, changes in physical fatigue and biological functions of Japanese female soccer players were investigated by determining changes in neutrophil and lymphocyte functions. Study subjects included 18 female soccer players. Body composition, serum myogenic enzymes, neutrophil function, including reactive oxygen species (ROS) production capability, phagocytic activity (PA) and serum opsonic activity, as well as lymphocyte subpopulation were measured before and after a soccer match. Levels of myogenic enzymes (AST, ALT, CK and LDH) and immunoglobulins (IgG and IgA) and complements (C3) increased significantly after the match. In addition, leukocyte, neutrophils and lymphocyte counts increased whereas total PA decreased significantly. The number of T and Th1 cells (subsets of T helper cells) decreased whereas Th2 increased significantly. In addition, the number of B cells increased and NK cells decreased significantly after the match. The match was found to result in degenerative changes in and damage to athlete muscle tissues together with damage‐ and change‐mediated stress. These data also suggest a post‐match accelerated inflammatory reaction and potential immunosuppression as indicated by reductions in neutrophil PA and lymphocyte functions. Copyright © 2012 John Wiley & Sons, Ltd.     

Effects of lower-leg rhythmic cuff inflation on cardiovascular autonomic responses during quiet standing in healthy subjects

To determine the effects of muscle pump function on cardiac autonomic activity in response to quiet standing, we simulated the muscle pump effect by rhythmic lower-leg cuff inflation (RCI) with four cuff pressures of 0 (sham), 40, 80, and 120 mmHg at 5 cycles/min. The R-R interval (RRI) and beat-to-beat blood pressure (BP) were acquired in healthy subjects (6 males and 5 females, aged 21-24 yr). From the continuous BP measurement, stroke volume (SV) was calculated by a pulse-contour method. Using spectral and cross-spectral analysis, RRI and systolic BP variability as well as the gain of spontaneous cardiac baroreflex sensitivity (sBRS) were estimated for the low- and high-frequency (HF) bands. Compared with the sham condition, RCI with cuff pressures of 80 and 120 mmHg led to increases in the mean RRI (P < 0.01) and HF power of RRI fluctuation (P < 0.05 for 80 mmHg and P < 0.01 for 120 mmHg) during quiet standing. Reduction in SV during standing was suppressed, and the sBRS of the HF band for standing were increased by RCI for either cuff pressure (P < 0.05 for 80 mmHg and P < 0.01 for 120 mmHg). However, at 40 mmHg RCI, these remained unchanged. These results suggest that, during standing, RCI of the lower leg increases cardiac vagal outflow when the cuff pressure is raised enough to oppose the hydrostatic-induced venous pressure in the calf.     

Effects of integrated polysensory recovery treatment on the functions of the central and autonomic nervous systems

The changes in the parameters of P300 cognitive evoked potentials, the psychological and emotional state, and heart rate variability parameters reflecting the characteristics of autonomic regulation during polysensory physiotherapeutic recovery treatment were studied. A single treatment with combined polysensory stimuli resulted in substantial activation of sympathetic regulation of the heart rate, improvement of the emotional state, and an increase in the P300 amplitude in the central frontal areas, which indicates activation of cognitive processes.     

On-line detection of sleep-wake states and application to produce intermittent hypoxia only in sleep in rats.

Sleep-disordered breathing is associated with adverse clinical consequences such as daytime sleepiness and hypertension. The mechanisms behind these associations have been studied in animal models, especially rats, but intermittent stimuli such as hypoxia have been applied without reference to sleep-wake states. To determine mechanisms underlying the adverse physiological consequences of stimuli associated with sleep-disordered breathing requires criteria for detection of sleep-wake states on-line to trigger stimuli only in sleep. This study aimed to develop such a system for freely behaving rats. Twelve rats with implanted electroencephalogram and neck electromyogram electrodes were studied in the light and dark phases. Electroencephalogram frequencies in the high (20-30 Hz) and low (2-4 Hz) frequency bands distinguished non-rapid eye movement (REM) sleep, whereas neck electromyogram distinguished REM. Using these parameters in a simple algorithm led to detection accuracies of 94.5 +/- 1.0 (SE) % for wakefulness, 96.2 +/- 0.8% for non-REM sleep, and 92.3 +/- 1.6% for REM compared with blinded human judgment. The algorithm was then used to trigger hypoxic stimuli only in sleep. Because frequency and amplitude analysis is readily performed using a variety of commercial systems, incorporation of these parameters into such an algorithm will facilitate studies investigating mechanisms underlying the physiological consequences of sleep-related respiratory stimuli in a fashion that more effectively models clinical disorders.     

Effects of short- and long-term pulsed radiofrequency electromagnetic fields on night sleep and cognitive functions in healthy subjects

There has been wide public discussion on whether the electromagnetic fields of mobile telephones and their base stations affect human sleep or cognitive functioning. As there is evidence for learning and memory-consolidating effects of sleep and particularly of REM sleep, disturbance of sleep by radiofrequency electromagnetic fields might also impair cognitive functions. Previously realized sleep studies yielded inconsistent results regarding short-term exposure. Moreover, data are lacking on the effect that short- and long-term exposure might have on sleep as well as on cognitive functions. Therefore, 10 healthy young male subjects were included and nocturnal sleep was recorded during eight consecutive nights. In the second, third, and last night, we investigated polysomnographic night sleep and cognitive functions. After the adaptation and baseline nights, the participants were exposed to a defined radiofrequency electromagnetic field during the following six nights. We analyzed polysomnographic night sleep according to Rechtschaffen and Kales [1968, Manual of Standardized Terminology, Techniques and Scoring System for Sleep of Human Subjects] as well as by power spectra and correlation dimension. Cognitive functions were investigated by an array of neuropsychological tests. Data analysis was done by comparing the baseline night with the first and last exposure night and the first two sleep cycles of the respective nights. We did not find significant effects, either on conventional sleep parameters or on power spectra and correlation dimension, nor were there any significant effects on cognitive functions. With our results, we are unable to reveal either short-term or cumulative long-term effects of radiofrequency electromagnetic fields on night sleep and cognitive functions in healthy young male subjects.     

Actigraphic estimates of sleep and the sleep-wake rhythm,and 6-sulfatoxymelatonin levels in healthy Dutch children

ABSTRACT

Sleep and the sleep-wake rhythm are essential for children’s health and well-being, yet reference values are lacking. This study therefore aimed to assess actigraphic estimates of sleep and the 24-h sleep-wake rhythm, as well as 6-sulfatoxymelatonin (aMT6s) levels in healthy children of different age groups. Additionally, relationships between the outcomes and sex, highest parental educational level (as an indication of socioeconomic status (SES)), and body-mass-index (BMI) were explored. In this cross-sectional study, healthy Dutch children (2–18 years) wore an actigraph (GT3x) for 7 consecutive days, collected first-morning void urine and completed a sleep log and sociodemographic questionnaire. Actigraphically estimated sleep variables were sleep onset latency (SOL), sleep efficiency (SE), total sleep time (TST), and wake after sleep onset (WASO). Non-parametric sleep-wake rhythm variables were intradaily variability (IV); interdaily stability (IS); the activity counts and timing of the least active 5-h period (L5counts and midpoint) and of the most active 10-h period (M10 counts and midpoint); and the relative amplitude (RA), i.e. the ratio of the difference and the sum of M10 and L5 counts. Finally, creatinine-corrected aMT6s levels were obtained by isotope dilution mass spectrometry. Effects of age group (preschool 2–5 years/school-aged 6–12 years/teenager 13–18 years), sex, highest parental educational level and BMI (Z-scores) were explored. Ninety-four children participated, equally divided across age groups (53% boys). Teenagers slept less, but more efficiently, than younger children, while their 24 h sleep-wake rhythm was the least stable and most fragmented (likely due to fragmentation of daytime activity). Additionally, aMT6s levels significantly declined over the age groups. Children from highly educated parents had lower sleep efficiency, but a more stable sleep-wake rhythm. Finally, sex or increase in BMI was not associated with any of the outcomes in this study. In conclusion, this study provides reference values of healthy children across different age groups and different sociodemographic factors. In the future, this information may help to better interpret outcomes in clinical populations.     

Effects of meals on objective and subjective measures of daytime sleepiness

Wells, Anita S., Nicholas W. Read, Chris Idzikowski, andJane Jones. Effects of meals on objective and subjective measures of daytime sleepiness. J. Appl.Physiol. 84(2): 507-515, 1998.Effects of recentfood ingestion on daytime sleepiness were assessed in 16 subjects (8 men and 8 women) who were each studied on two occasions, 28 days apart.On each occasion, subjects ate a high-fat low-carbohydrate (CHO)(fat/CHO energy ratio 54:41) meal and an isoenergetic low-fat high-CHOmeal (fat/CHO energy ratio 7:88) 4 h apart in a counterbalanced order.Sleepiness was measured at 2-h intervals by using the Multiple SleepLatency Test and the Akerstedt electroencephalograph sleepiness test.To control for circadian factors, one group (4 men, 4 women) ate themeals 2 h later than did the other group of subjects. There were nodifferences in sleepiness according to the composition of the meal.Sleepiness in the Multiple Sleep Latency Test was significantly greater1.5 h after the meals were eaten than before (F 11.37; df 1,15;P = 0.004). Sleepiness was alsoenhanced in the Akerstedt sleepiness test 3 h 20 min after the meals.The results suggest that the meals induced an enhancement in sleepiness that was not solely due to circadian rhythms.