Heart rate variability in domestic chicken lines genetically selected on feather pecking behavior

Domestic chicken lines of the White Leghorn type differing in their level of feather pecking were developed by divergent genetic selection specifically on feather pecking behavior. We determined parameters of heart rate variability to elucidate the relative activation of the sympathetic and parasympathetic nervous systems during rest and stressful situations. A total of 48 hens were tested in 8 batches. Segments of 2 min were extracted from electrocardiograms recorded by radio-transmitter implants, before (basal undisturbed conditions) and during physical restraint and a social test. Under basal conditions mean distance between R-waves were shorter in the low and high lines compared to the control. During physical restraint, stress reactions [reduced root of the mean squares of successive differences (RMSSD), reduced high frequency (HF), high low frequency (LF/HF) and low vagal-sympathetic effect (VSE) compared to basal levels] were significant in all lines. During the physical restraint the high feather pecking (HFP) line reacted significantly stronger than control (CON) and low feather pecking (LFP) line. During social test the LFP line reacted different than the other two lines. Seemingly birds from LFP conceived the social test as less stressful than birds from the CON and HFP lines. From this it follows that (1) physical restraint generally induced higher stress reactions than the social test and (2) genetic selection for higher levels of feather pecking increased the autonomic nervous system reaction to physical restraint whereas selection against feather pecking has reduced the response to increased social contact.     

Effects of Work and Orcadian Rhythm on Bus Drivers' Oral Temperature

The results described in this paper originate from a research project aiming at the development of a useful measuring instrument which can demonstrate the effect of work and work circumstances on the task performer. Among other physiological (and psychometric) variables, oral temperature data were obtained from eight younger and eight older bus drivers working in various shifts. Measurements were performed in an experimental design under standardized conditions in a mobile laboratory before starting, during some rest intervals, and after finishing work. The same measurements were performed on the bus drivers in a control condition at corresponding times on a day off. The results indicated that only during the working days a temperature pattern could be detected resembling the data found in the literature (low in the morning, a maximum in the late afternoon, then a decline). No clear pattern was discernible on work-free days. On working days the mean oral temperature values were significantly higher at corresponding hours of the day. Upward deviations of the temperature pattern were found before starting work (but also at the beginning of the day off), while lower values were obtained after finishing work (especially in the shifts starting in the morning). These results might be interpreted in terms of interaction between circadian rhythm and activating and de-activating tendencies connected with (structured) daily activities.     

Effects of Work and Orcadian Rhythm on Bus Drivers' Oral Temperature

The results described in this paper originate from a research project aiming at the development of a useful measuring instrument which can demonstrate the effect of work and work circumstances on the task performer. Among other physiological (and psychometric) variables, oral temperature data were obtained from eight younger and eight older bus drivers working in various shifts. Measurements were performed in an experimental design under standardized conditions in a mobile laboratory before starting, during some rest intervals, and after finishing work. The same measurements were performed on the bus drivers in a control condition at corresponding times on a day off. The results indicated that only during the working days a temperature pattern could be detected resembling the data found in the literature (low in the morning, a maximum in the late afternoon, then a decline). No clear pattern was discernible on work-free days. On working days the mean oral temperature values were significantly higher at corresponding hours of the day. Upward deviations of the temperature pattern were found before starting work (but also at the beginning of the day off), while lower values were obtained after finishing work (especially in the shifts starting in the morning). These results might be interpreted in terms of interaction between circadian rhythm and activating and de-activating tendencies connected with (structured) daily activities.     

Regional blood volume and peripheral blood flow in postural tachycardia syndrome

Variants of postural tachycardia syndrome (POTS) are associated with increased ["high-flow" POTS (HFP)], decreased ["low-flow" POTS (LFP)], and normal ["normal-flow" POTS (NFP)] blood flow measured in the lower extremities while subjects were in the supine position. We propose that postural tachycardia is related to thoracic hypovolemia during orthostasis but that the patterns of peripheral blood flow relate to different mechanisms for thoracic hypovolemia. We studied 37 POTS patients aged 14-21 yr: 14 LFP, 15 NFP, and 8 HFP patients and 12 healthy control subjects. Peripheral blood flow was measured in the supine position by venous occlusion strain-gauge plethysmography of the forearm and calf to subgroup patients. Using indocyanine green techniques, we showed decreased cardiac index (CI) and increased total peripheral resistance (TPR) in LFP, increased CI and decreased TPR in HFP, and unchanged CI and TPR in NFP while subjects were supine compared with control subjects. Blood volume tended to be decreased in LFP compared with control subjects. We used impedance plethysmography to assess regional blood volume redistribution during upright tilt. Thoracic blood volume decreased, whereas splanchnic, pelvic, and leg blood volumes increased, for all subjects during orthostasis but were markedly lower than control for all POTS groups. Splanchnic volume was increased in NFP and LFP. Pelvic blood volume was increased in HFP only. Calf volume was increased above control in HFP and LFP. The results support the hypothesis of (at least) three pathophysiologic variants of POTS distinguished by peripheral blood flow related to characteristic changes in regional circulations. The data demonstrate enhanced thoracic hypovolemia during upright tilt and confirm that POTS is related to inadequate cardiac venous return during orthostasis.     

Searching for preventive measures of cardiovascular events in aged Japanese taxi drivers--the daily rhythm of cardiovascular risk factors during a night duty day

Previous studies have shown that Japanese taxi drivers are exposed to more risk factors and have a higher mortality rate due to cardiovascular disease than other occupational groups. We investigated the effect of night taxi driving with a view to preventing acute events of cardiovascular disease among aged taxi drivers. Twenty-nine taxi drivers (41-67 years old) were examined for urine normetanephrine/creatinine, von Willebrand factor, anti-thrombin III, t-plasminogen activator-plasminogen activator inhibitor 1-complex, hematocrit, blood glucose and blood pressure in the morning and at midnight during a duty day and in the following morning. At the same time, the blood pressure and blood glucose of 46 taxi drivers (43-67 years old) in the morning after a night duty with little sleep and in the morning after daytime work and subsequent night sleep were compared. The results obtained indicate that the aggravation of sympathetic nervous system functions with disturbed circadian rhythms, increased blood coagulation and blood concentration, endothelial injury and the elevation of blood glucose at midnight or the next morning were induced by their night work. These conditions are supposed to favour acute vascular events in aged taxi drivers. Preventive measures considered include social support for anticoagulant food and water intake, short exercise and walking as well as taking a rest and a nap during night work.     

Daily variation in body core temperature using radio-telemetry in aluminium industry shift-workers

The aim of this study was to investigate the diurnal variation in core temperature in aluminium shift-workers exposed to hot ambient conditions. Core temperature was continuously recorded via an ingestible radio-telemetry thermistor in 29 shift-workers. Data from the morning, afternoon and night shifts were aggregated for each participant to obtain 24-h recordings during work duties. Complete data were obtained from 10 participants. Results showed that body core temperatures recorded in the afternoon (from 12:00 h to 20:00 h) were significantly higher (P<0.05) than in the late evening, night and early morning (from 21:00 h to 08:00 h). In addition, core temperature displayed a circadian variation with a mesor of 37.45 (±0.19) °C, an amplitude of 0.23 (±0.12) °C and an acrophase at 16:36 h (±3:37 h). The peak values of core temperature recorded at each hour of the day on the work site followed the same pattern with an acrophase in the early afternoon. In summary, our data showed that shift-workers present higher core temperatures in the afternoon than in the morning or during the night. In addition, it was not the work duration but the hour-of-day that triggered the variation in core temperature. This result partly explains previous observations that workers under heat stress have a higher probability of heat illness during daytime shifts than during the night shift, and suggests that special care should be given to the afternoon shift and to the end of the morning shift.     

Updating the “Risk Index”: A systematic review and meta-analysis of occupational injuries and work schedule characteristics

Fatigue is a major risk factor for occupational ‘accidents’ and injuries, and involves dimensions of physical, mental, and muscular fatigue. These dimensions are largely influenced by temporal aspects of work schedules. The “Risk Index” combines four fatigue-related components of work schedules to estimate occupational ‘accident’ and injury risk based on empirical trends: shift type (morning, afternoon/evening, night), length and consecutive number, and on-shift rest breaks. Since its first introduction in 2004, several additional studies have been published that allow the opportunity to improve the internal and external validity of the “Risk Index”. Thus, we updated the model’s estimates by systematically reviewing the literature and synthesizing study results using meta-analysis. Cochrane Collaboration directives and MOOSE guidelines were followed. We conducted systematic literature searches on each model component in Medline. An inverse variance approach to meta-analysis was used to synthesize study effect sizes and estimate between-studies variance (‘heterogeneity’). Meta-regression models were conducted to explain the heterogeneity using several effect modifiers, including the sample age and sex ratio. Among 3,183 initially identified abstracts, after screening by two independent raters (95–98% agreement), 29 high-quality studies were included in the meta-analysis. The following trends were observed: Shift type. Compared to morning shifts, injury risk significantly increased on night shifts (RR = 1.36 [95%CI = 1.15–1.60], n = 14 studies), while risk was slightly elevated on afternoon/evening shifts, although non-significantly (RR = 1.12 [0.76–1.64], n = 9 studies). Meta-regressions revealed worker’s age as a significant effect modifier: adolescent workers (≤ 20 y) showed a decreased risk on the afternoon/evening shift compared to both morning shifts and adult workers (p < 0.05). Number of consecutive shifts. Compared to the first shift in a block of consecutive shifts, risk increased exponentially for morning shifts (e.g., 4th: RR = 1.09 [0.90–1.32]; n = 6 studies) and night shifts (e.g., 4th: RR = 1.36 [1.14–1.62]; n = 8 studies), while risk on afternoon/evening shifts appeared unsystematic. Shift length. Injury risk rose substantially beyond the 9th hour on duty, a trend that was mirrored when looking at shift lengths (e.g., >12 h: RR = 1.34 [1.04–1.51], n = 3 studies). Rest breaks. Risk decreased for any rest break duration (e.g., 31–60 min: RR = 0.35 [0.29–0.43], n = 2 studies). With regards to time between breaks, risk increased with every additional half hour spent on the work task compared to the first 30 min (e.g., 90–119 min: RR = 1.62 [1.00–2.62], n = 3 studies). Rest break duration and interval seem to interact such that with increasing duration, the time between breaks becomes irrelevant. The updated “Risk Index”. All four components were combined to form the updated model and the relative risk values estimated for a variety of work schedules. The resulting “Risk Map” shows regions of highest risk when rest breaks are not taken frequently enough (i.e. <4 h) or are too short (i.e. <30 min), when shift length exceeds 11 h, and when work takes place during the night (particularly for >3 consecutive night shifts). The “Risk Index” is proposed as an empirical model to predict occupational ‘accident’ and injury risk based on the most recent data in the field, and can serve as a tool to evaluate hazards and maximize safety across different work schedules.     

Health conditions of bus drivers in a 6 year follow up study

The bus drivers of a public bus company, working in a fast rotating 4 shift system from 05.00 to 24.30, were examined in 1993 (230 persons) and 1999 (266 persons). The comparison between the two years showed no significant differences for all the parameters evaluated by the Standard Shiftwork Index and medical examination. In both surveys work organisation was considered "efficient-fairly good" by most workers, who were mostly satisfied with their job. Work load was rated significantly higher for "afternoon" and "morning" shifts, during which most accidents at work and "in itinere" occurred. Night sleep was reduced by 3 hours on "early" shift and about 2 hours on "morning" shifts. The most prevalent health troubles dealt with low back pain, gastritis, headache and haemorrhoids. Neuroticism was the trait more correlated with poorer health conditions, whereas shiftwork exposure appeared as a significant predictor of risk of critical Effort/Reward Imbalance and minor psychological disorders. Both extrinsic and intrinsic efforts significantly increased with age, but not reward. The comparison of the same cohort of 108 persons examined both in 1993 and in 1999 showed a significant increase of low back pain, gastrointestinal troubles, haemorrhoids and lipids disorders.     

Flow cytometric analysis of mitochondrial populations in HL-CMS systems of rice under H2O2 stress

Cytoplasmic male sterility (CMS) has often been associated with mitochondrial dysfunction. In this report, the heterogeneity of mitochondria was analyzed in both Honglian (HL) CMS (YtA) rice seedlings and those of its corresponding maintainers (YtB) by flow cytometry and staining with rhodamine-123 (Rh-123). Both lines revealed two distinct fluorescence populations: high fluorescence populations (HFP) and light fluorescence populations (LFP), and a somewhat lower LFP/HFP ratio was detected in conjunction with the higher reactive oxygen species (ROS) content in YtA. In addition, use of the specific effector hydrogen peroxide (H₂O₂) demonstrated a correlation between the LFP/HFP ratio and ROS levels in both lines. Higher ROS content caused a more swift decrease of F₀F₁-ATPase activity and ATP contents in YtA than those in YtB, which accompanied with an obvious decline of the LFP/HFP ratio in YtA. Furthermore, a mitochondrial genomic DNA smear was detected by pulsed field gel electrophoresis. Taken together, these results implied that HL-CMS line rice seedlings and those of its corresponding maintainer have different proportion of Rh-123 staining mitochondria populations, which may be accounted for by ROS contents on the basis of ATPase activity and ATP contents.     

QT-RR hysteresis is caused by differential autonomic states during exercise and recovery

QT-RR hysteresis is characterized by longer QT intervals at a given RR interval while heart rates are increasing during exercise and shorter QT intervals at the same RR interval while heart rates are decreasing during recovery. It has been attributed to a lagging QT response to different directional changes in RR interval during exercise and recovery. Twenty control subjects (8 males, age 51 ± 6 yr), 16 subjects with type 2 diabetes (12 males, age 56 ± 8 yr), 71 subjects with coronary artery disease (CAD) and preserved left ventricular ejection fraction (LVEF) (≥50%) (51 males, age 59 ± 12 yr), and 17 CAD subjects with depressed LVEF (<50%) (13 males, age 57 ± 10 yr) underwent two 16-min exercise tests followed by recovery. In session 2, parasympathetic blockade with atropine (0.04 mg/kg) was achieved at end exercise. QT-RR hysteresis was quantified as: 1) the area bounded by the QT-RR relationships for exercise and recovery in the range of the minimum RR interval at peak exercise to the minimum RR interval + 100 ms and 2) the difference in QT interval duration between exercise and recovery at the minimum RR interval achieved during peak exercise plus 50 ms (ΔQT). The effect of parasympathetic blockade was assessed by substituting the QT-RR relationship after parasympathetic blockade. QT-RR hysteresis was positive in all groups at baseline and reversed by parasympathetic blockade (P < 0.01). We conclude that QT-RR hysteresis is not caused by different directional changes in RR interval during exercise and recovery. Instead, it is predominantly mediated by differential autonomic nervous system effects as the heart rate increases during exercise vs. as it decreases during recovery.     

The effect of wai tan kung on autonomic nervous modulation in the elderly

The decline in physical capacity in the elderly can be ameliorated by low-velocity, low-impact exercises. Wai tan kung (WTK), a traditional Taiwanese conditioning exercise, is suitable for older people. This study evaluated the effect of WTK on autonomic nervous modulation in the elderly. Twenty WTK practitioners and 20 normal controls were recruited in this study. The stationary state spectral heart rate variability (HRV) measures, hemodynamics, and spirometry between the WTK group and normal controls and sequential changes in HRV measures and hemodynamics after WTK were compared. We found that the standard deviation and coefficient of variation of RR intervals, total power, low frequency power (LFP), and normalized LFP (nLFP) in WTK practitioners before WTK were all significantly higher than those of normal controls. After WTK, the normalized high-frequency power increased (nHFP) significantly from 27.7±13.2 normalized units (nu) before WTK to 37.6±16.0 nu 30 min after WTK, and to 39.8±20.1 nu 60 min after WTK. In contrast, LFP/HFP decreased significantly from 1.3±1.0 before WTK to 1.0±0.9 30 min after WTK and to 0.8±0.6 60 min after WTK. We concluded that in the short term, WTK enhances vagal modulation and suppresses sympathetic modulation, whereas in the long term, WTK enhances sympathetic modulation without compromising vagal modulation of the elderly. Thus WTK is good health-promoting calisthenics that can be recommended to the elderly.     

Heart rate variability in women exposed to very cold air (−110 °C) during whole-body cryotherapy

Heart rate monitoring was used to measure heart rate variability (HRV) at thermoneutral conditions (Ta 24 °C) in healthy women resting in supine position before and after acute and after repeated (3 times a week during a 3-month period) whole-body cryotherapies (WBC), at −110 °C. The observed acute cooling-related increase in high frequency power (HFP) of RR-intervals indicates an increase in cardiac parasympathetic modulation. After 3 months of repeated WBC the increase in parasympathetic tone was attenuated, which may be interpreted as an adaptation of autonomic function. The repeated WBC exposures-related increase in resting low frequency power (LFP) of RR-intervals during the 3 months resembles the response observed related to exercise training.     

体位改变对Beagle犬心脏自主神经控制的影响

目的观察体位改变对Beagle犬心脏自主神经控制的影响。方法利用大动物无创生理遥测技术,监测清醒活动状态下雌性Beagle犬在静态姿势（lying、standing、sitting、hanging）和运动（walking）姿势下的心电图（ECG）,并用HRV功率谱分析其自主神经功能。结果在静态姿势下,Beagle犬RR间期（RRI）、RR间期的标准差SDNN（SDNN）、相邻RR间期差值平方和的均方根RMSSD（RMSSD）、相邻R-R间期差值〉50 ms的窦性个数占心搏总数的百分比pNNabs（50）（pNNabs（50））、TP总功率（TP）、VLF极低频功率（VLF）、标准化高频功率（HFnorm）均明显高于运动状态（P〈0.05,P〈0.01）,而心率（HR）、标准化低频功率（LFnorm）和低频功率/高频功率（LF/HF）平衡指数则明显低于运动状态（P〈0.05,P〈0.01）。结论不同体位姿势在静息状态下以迷走神经活动兴奋为主,相反,在运动状态下以交感神经活动兴奋为主;体位姿势改变能引起心率的变化,必然影响心脏自主神经控制能力,其主要取决于迷走神经活动强弱有关,且导致LF/HF均衡性的破坏。     

When does stress end? Evidence of a prolonged stress reaction in shiftworking truck drivers

This study aimed to analyze individual cortisol levels in relation to work conditions, sleep, and health parameters among truck drivers working day shifts (n = 21) compared to those working irregular shifts (n = 21). A total of 42 male truck drivers (39.8 (+/-) 6.2 yrs) completed questionnaires about sociodemographics, job content, work environment, health, and lifestyle. Rest-activity profiles were measured using actigraphy, and cardiovascular blood parameters were collected. Salivary cortisol samples were obtained: (i) at waking time, (ii) 30?min after waking, and (iii) at bedtime, during both one workday and one day off from work. Irregular-shift workers, compared to day-shift workers, showed significantly higher waist-hip ratio, very-low-density lipoprotein (VLDL) cholesterol, tiredness after work, years working as a driver, truck vibration, and less job demand (p < .05). High cortisol levels in irregular-shift workers were correlated with certain stressors, such as short sleep duration and low job satisfaction, and to metabolic parameters, such as total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), VLDL, and triglycerides. Day-shift workers had higher cortisol levels collected 30?min after waking (p = .03) and a higher cortisol awakening response (CAR; p = .02) during workdays compared to off days. Irregular-shift workers had higher cortisol levels on their off days compared to day-shift workers (p = .03). In conclusion, for the day-shift workers, a higher cortisol response was observed on workdays compared to off days. Although no direct comparisons could be made between groups for work days, on off days the irregular-shift workers had higher cortisol levels compared to day-shift workers, suggesting a prolonged stress response in the irregular-shift group. In addition, cortisol levels were correlated with stressors and metabolic parameters. Future studies are warranted to investigate further stress responses in the context of irregular work hours.     

Local vascular responses affecting blood flow in postural tachycardia syndrome

Postural tachycardia syndrome (POTS) is defined by orthostatic intolerance associated with abnormal upright tachycardia. Some patients have defective peripheral vasoconstriction and increased calf blood flow. Others have increased peripheral arterial resistance and decreased blood flow. In 14 POTS patients (13-19 yr) evenly subdivided among low-flow POTS (LFP) and high-flow POTS (HFP) we tested the hypothesis that myogenic, venoarteriolar, and reactive hyperemic responses are abnormal. We used venous occlusion plethysmography to measure calf venous pressure and blood flow in the supine position and when the calf was lowered by 40 cm to evoke myogenic and venoarteriolar responses and during venous hypertension by 40-mmHg occlusion to evoke the venoarteriolar response. We measured calf reactive hyperemia with plethysmography and cutaneous laser-Doppler flowmetry. Baseline blood flow in LFP was reduced compared with HFP and control subjects (0.8 +/- 0.2 vs. 4.4 +/- 0.5 and 2.7 +/- 0.4 ml.min-1.100 ml-1) but increased during leg lowering (1.2 +/- 0.5 ml.min-1. 100 ml-1) while decreasing in the others. Baseline peripheral arterial resistance was increased in LFP and decreased in HFP compared with control subjects (39 +/- 13 vs. 15 +/- 3 and 22 +/- 5 mmHg.ml-1. 100 ml. min) but decreased to 29 +/- 13 mmHg.ml-1.100 ml. min in LFP during venous hypertension. Resistance increased in the other groups. Maximum calf hyperemic flow and cutaneous flow were similar in all subjects. The duration of hyperemic blood flow was curtailed in LFP compared with either control or HFP subjects (plethysmographic time constant = 20 +/- 2 vs. 29 +/- 4 and 28 +/- 4 s; cutaneous time constant = 60 +/- 25 vs. 149 +/- 53 s in controls). Local blood flow regulation in low-flow POTS is impaired.     

Driving and subsidiary behavior of taxi drivers working alternate-day shifts.

A field study on taxi drivers working alternate-day shifts of prescribed duration of 16 hr of work revealed that most of them actually worked longer for 16 hr 50 min on the average, starting from 7:00 and ending later than 2:00. The mean hourly income greatly increased in hours later than 22:00 due to the increased fare per hire and higher speed, so that these hours were regarded by the drivers as the most important period of the day. This resulted in retarded mean bedtime of 5:31 after the shift end and in reduced sleep. The total rate of subsidiary activities of the drivers decreased during the middle of the day, but increased towards the shift end. Those activities having a relatively low rate at the beginning, such as subsidiary lower limb movements, shoulder-neck movements, and yawning, remarkably increased in the late evening and midnight hours. These activities increased even during frequent driving operations and tended to relate with each other, often recurring in bursts especially while feeling drowsy. The incentive wage system of the drivers thus accounts not only for the extraordinarily long working hours but also for intensified night work.     

A circadian rhythm in heart rate variability contributes to the increased cardiac sympathovagal response to awakening in the morning

Morning hours are associated with a heightened risk of adverse cardiovascular events. Recent evidence suggests that the sleep-wake cycle and endogenous circadian system modulate cardiac function in humans and may contribute to these epidemiological findings. The aim of the present study was to investigate the interaction between circadian and sleep-wake-dependent processes on heart rate variability (HRV). Fifteen diurnally active healthy young adults underwent a 72-h ultradian sleep-wake cycle (USW) procedure (alternating 60-min wake episodes in dim light and 60-min nap opportunities in total darkness) in time isolation. The present study revealed a significant main effect of sleep-wake-dependent and circadian processes on cardiac rhythmicity, as well as a significant interaction between these processes. Turning the lights off was associated with a rapid increase in mean RR interval and cardiac parasympathetic modulation (high-frequency [HF] power), whereas low-frequency (LF) power and sympathovagal balance (LF:HF ratio) were reduced (p?≤?.001). A significant circadian rhythm in mean RR interval and HRV components was observed throughout the wake and nap episodes (p?≤?.001). Sleep-to-wake transitions occurring in the morning were associated with maximal shifts towards sympathetic autonomic activation as compared to those occurring during the rest of the day. Namely, peak LF:HF ratio was observed in the morning, coincidental with peak salivary cortisol levels. These results contribute to our understanding of the observed increase in cardiovascular vulnerability after awakening in the morning.     

Prevalence and correlates of poor sleep quality and daytime sleepiness in Belgian truck drivers

Sleepiness and sleep complaints are common among professional drivers. Sleepiness is a considerable problem not only because it affects the drivers' well-being, but also because of the consequences for performance and safety. Assessment of the (self-reported) prevalence and research into the risk factors are thus an important health issue and are also indispensable to prevent productivity loss and work-related accidents and injuries. Therefore, the aim of this study was to describe sleeping, driving, and health characteristics of Belgian truck drivers and to determine occupational and individual factors associated with poor sleep quality and daytime sleepiness. Cross-sectional data were collected using a self-administered questionnaire that included the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Berlin Questionnaire (BQ). The mean (SD) age of the 476 studied truck drivers was 42.7 (10.2) yrs and the mean (SD) body mass index was 27.3 (5.1) kg/m(2). Approximately 47% declared that they drove >50 h/wk and found their work schedule unrealistic. The mean (SD) PSQI score was 4.45 (2.7); poor quality of sleep (PSQI >5) was found in 27.2%. The mean (SD) ESS score was 6.79 (4.17); 18% had a score >10. The BQ indicated that 21.5% had a higher risk on obstructive sleep apnea. In multiple logistic regression analysis, low educational level (odds ratio [OR] 1.86), current smoking (OR 1.75), unrealistic work schedule (OR 1.75), and risk for obstructive sleep apnea (OR 2.97) were found to be independent correlates of daytime sleepiness. Poor sleep quality was significantly associated with poor self-perceived health (OR 1.95), unrealistic work schedule (OR 2.85), low job satisfaction (OR 1.91), and less driving experience (OR 1.73). These results show that poor sleep quality and daytime sleepiness were prevalent in Belgian truck drivers. Taking into account that several significant correlates with respect to these sleep problems were identified both at the individual and the occupational level, comprehensive countermeasures to improve working conditions and organization are needed, as well as health promotion interventions, to ensure the safety and well-being of truck drivers.     

Hypersomnolence and accidents in truck drivers: A cross-sectional study

Truck drivers are more likely to suffer severe injury and death due to certain truck driving characteristics. Identifying and preventing factors associated with accidents in this population is important to minimize damage and improve road safety. Excessive daytime sleepiness is a major public health problem, leading to impaired cognitive function, reduced alertness, and increased risk of motor vehicle crashes. The aim of this cross-sectional study was to determine the prevalence and predictors of hypersomnolence (defined as an Epworth Sleepiness Scale score greater than 10) among truck drivers. Three hundred male truck drivers were studied. Quality of sleep was assessed by the Pittsburgh Sleep Quality Index, and the association between demographic, clinical, and occupational data with excessive sleepiness was analyzed. The mean daily sleep duration was 5.6+/-1.3 h, and poor quality of sleep was found in 46.3% of the individuals. Hypersomnolence was found in 46% of the drivers and was associated with younger age, snoring, and working >10 h without rest. A positive correlation between hypersomnolence and previous accidents was detected (p=0.005). These results show that sleep deprivation and hypersomnolence are frequent among truck drivers. The treatment of sleep-disordered breathing and the implementation of educational programs, particularly targeting younger drivers and promoting increased awareness of the deleterious effects of sleep loss and work overload, may help to reduce hypersomnolence and accidents among truck drivers.