Shift work and cardiovascular strain on working and non-working days.

BACKGROUND: Shift work is often associated with adverse effects on cardiovascular health of employees. Only a few studies address the strain of shift and day workers on non-working days compared to working days. AIMS: This study aims to determine how the cardiovascular strain of hotel and catering industry (HCI) employees who work alternating shifts differs from those working normal day shifts-on both a working day (WD) and a non-working day (ND). METHODS: The sample consisted of 60 alternating shift (morning and afternoon, mean age: 31.5 ± 8.5 years) and 88 day workers (mean age: 35.3 ± 9.4 years). A 24-h ambulatory measurement of blood pressure (BP) and heart rate (HR) on WD and ND with the time phases DAY, SLEEP, and 24-h TOTAL was used to analyse cardiovascular strain. BP status was assessed by self-measurement (36% hypertensives). RESULTS: The total strain over 24 h was slightly higher on WD than ND (mean BP: 134/79 versus 127/75 mmHg, P = 0.002-0.020; mean HR: 78 versus 75 bpm, P = 0.055). In trend, shift workers had higher systolic BP than day workers during the individual time phases of DAY, SLEEP, and 24-h TOTAL on WD. Known cardiovascular risk factors emerged as critical determinants of cardiovascular strain: older age, male gender, and hypertensive blood pressure status. CONCLUSIONS: The results revealed no clear association between the alternating shift system in HCI and increased cardiovascular strain. The 24-h ambulatory measurement is considered ideal for determining cardiovascular strain in everyday life and under working conditions.

Nutrition and health in hotel staff on different shift patterns.

BACKGROUND: Limited research is available that examines the nutritional behaviour and health of hotel staff working alternating and regular shifts. AIMS: To analyse the nutritional behaviour and health of employees working in alternating and regular shifts. METHODS: The study used an ex post facto cross-sectional analysis to compare the nutritional behaviour and health parameters of workers with alternating shifts and regular shift workers. Nutritional behaviour was assessed with the Food Frequency Questionnaire. Body dimensions (body mass index, waist hip ratio, fat mass and active cell mass), metabolic values (glucose, triglyceride, total cholesterol and low- and high-density lipoprotein), diseases and health complaints were included as health parameters. RESULTS: Participants worked in alternating (n = 53) and regular shifts (n = 97). The average age of subjects was 35 ± 10 years. There was no significant difference in nutritional behaviour, most surveyed body dimensions or metabolic values between the two groups. However, alternating shift workers had significantly lower fat mass and higher active cell mass but nevertheless reported more pronounced health complaints. Sex and age were also confirmed as influencing the surveyed parameters. CONCLUSIONS: Shift-dependent nutritional problems were not conspicuously apparent in this sample of hotel industry workers. Health parameters did not show significantly negative attributes for alternating shift workers. Conceivably, both groups could have the same level of knowledge on the health effects of nutrition and comparable opportunities to apply this. Further studies on nutritional and health behaviour in the hotel industry are necessary in order to create validated screening programmes.

[Age-related effects on mental ability and their associations with personal characteristics among female teachers]. / Altersbezogene Effekte mentaler Leistungsfähigkeit und deren Zusammenhang zu personenbezogenen Merkmalen bei Lehrerinnen.

AIM: Mental ability is considered as a resource that supports coping processes among teachers. It consists of fluid speed-orientated components and crystallised precision-orientated components. Both components are subject to differential aging processes and are affected by personal factors. In this context, the effects of age and the correlation between mental ability and personal factors are analysed for a set of younger and older female teachers. METHODS: The data collection was carried out during extended preventive medical examinations at schools in Saxony. The analysis included the data of 252 female teachers. Mental ability was measured with standardised and validated instruments. Data were collected for the verbal and cognitive abilities to respond, to reset, to concentrate, to remember and to orientate as well as for strategy development. These variables were assigned to the speed-orientated and the precision-orientated components on the basis of measurements of time and errors. Personal factors included sense of coherence, susceptibility to stress, incapacity to recover, mental health and health complaints. In order to analyse age effects, the female teachers were divided into 2 age groups (< 45 and 45 years). RESULTS: The fluid components of mental ability showed significant but small effects in favour of the younger age group. No significant difference was found for the crystallised components among the age groups. In both age groups mental ability had a more favourable value for the teachers compared to the general population. The personal factors showed no differences for younger and older teachers, with the exception of physical health complaints which were mentioned more often by older teachers. Only a few very small correlations were detectable between the components of mental ability and personal factors. CONCLUSIONS: Besides the favourable mental ability of the teachers, the hypothesised and expected age effects are confirmed: the fluid abilities decline with age while the crystallised abilities remain stable. This is a starting point for prevention and intervention. Training allows maintenance or an improvement of mental ability at any age. Multidirectional correlations exist between mental ability and personal factors. Since mental ability comprises far more components than those considered in this study, the research approach should be expanded in the future.

A comparative analysis of the Work Ability Index.

BACKGROUND: The Work Ability Index (WAI) is a well-established instrument to measure work ability. However, the dimensionality of the WAI remains controversial. AIMS: To identify the dimensionality of the WAI and to investigate dependencies of factors and subscales. METHODS: The sample analysed in this study consisted of 371 subjects of different occupational groups (teachers, office workers, nursery school teachers and managers). The WAI was measured for all subgroups. Psychometric characteristics of the WAI were investigated using factor analyses with different numbers and different patterns of dependency among the factors. Chi-square analysis and the Comparative Fit Index were used to statistically assess fit quality. RESULTS: The group of managers had to be excluded from the analysis as their results were probably overoptimistic due to reporting bias; thus, 324 subjects entered. The one-factor model and an orthogonal two-factor model did not fit the observed correlational structures. A satisfactory fit was obtained using a two-dimensional model with correlated factors. These factors could be interpreted as subjectively estimated work ability and objective health status. Only five of seven items of the WAI could be related unambiguously to one of both factors. CONCLUSIONS: From our study, we conclude that using only the total score of the WAI is not adequate for population analysis of and assessment of work ability to individuals. Instead, the two-dimensional structure of the instrument must be taken into account.

Sympathetic and parasympathetic activation in heart rate variability in male hypertensive patients under mental stress.

Disturbed sympathetic and also parasympathetic activity of the autonomic nervous system points to pathological alterations in the cardiovascular system. Untreated hypertensive subjects were examined with respect to the question of whether an increase in sympathetic activity necessarily goes along with a reduction in parasympathetic activity, and whether 'delayed' recovery behaviour after mental stress could be an indicator of a disturbed cardiovascular function. In 20 male hypertensive (HT) and 20 normotensive (NT) subjects (control group), heart rate variability (HRV) was compared during rest and under mental stress. The testing procedure consisted of the following phases: habituation, arithmetic tasks without and with interference, recovery. HRV was analysed using the trigonometric regressive spectral analysis (TRS). Proceeding from the total variance (ms2), the weighted averaged frequency (Hz) and the variance parts (ms2) in the frequency bands 'low frequency' (LF-band: 0.04-0.15 Hz) and 'high frequency' (HF-band: 0.15-0.40 Hz) were explored. The variance part modulated by spontaneous breathing within the HF-band was assessed additionally. The variance part in the LF-band under mental stress was significantly increased in the HT group (P<0.01). Activity in the HF-band (without the respiration-dependent part) under mental stress did not differ between both groups, whereas the breathing-modulated part of variance in the HF-band was reduced in the HT subjects. During the recovery period in the HT group, the weighted averaged frequency was still elevated compared to baseline, and the variance part in the LF-band was increased, which may point to delayed recovery behaviour. In addition, by using a discriminant analysis 85% of all subjects were reclassified to the original groups, all HT subjects being assigned 'correctly'. Spectral variance parameters enable early discovery of altered cardiovascular regulation. Respiration influences variance in the HF-band in hypertensive subjects and should therefore be paid attention to. The variance part in the LF-band, weighted averaged frequency and the respiration-modulated variance in the HF-band turned out to be the most valid parameters for the differentiation between NT and HT subjects.

Peripheral and brachial blood pressure during standardized occupation-related tests in normotensive and mild hypertensive men and women.

We investigated the usefulness of peripheral blood pressure (BP) measurement in the assessment of strain in occupational physiology. Our hypothesis was that the brachial and peripheral BP reflect physiologically different events under various occupation-related demands in normotensive (NT) and hypertensive (HT) people. A group of 20 female and 20 male subjects with unmedicated mild hypertension that had been diagnosed by ambulatory blood pressure monitoring [awake time systolic/diastolic BP (BPs/BPd) 142.9 (SD 11.3)/86.4 (SD 6.2) mmHg] and 40 NT matched by age and sex [BPs/BPd 120.0 (SD 9.8)/75.6 (SD 5.9) mmHg] attended a laboratory session to undertake mental arithmetic tasks, a fingergrip test and submaximal cycle ergometry. Brachial and peripheral BP as well as heart rate were measured using a sphygmomanometer and an continuously automatic blood pressure measuring device on the finger, respectively. The peripheral BPs was higher than brachial BPs, BPd was similar for peripheral and brachial BP except during cycle ergometry. Associations between the levels of brachial and peripheral BP depended on demands and did not explain more than 42% of the common variance. The highest correlations between the two BP methods were observed during habituation, recovery and mental demands, and weak correlations during cycle ergometry. For peripheral BPs and BPd we found significant correlations in all phases of the test (r = 0.58 to 0.86, P < 0.001), also in ergometry (NT r = 0.62, P < 0.001, HT r = 0.53, P < 0.001), in contrast to the brachial BP. Peripheral BP differentiated the two BP groups (57.5%-72.5% correctly classified) which had been grouped by daily measurement of brachial BP, but brachial BP was superior in this respect with 65.0%-87.5% being correctly classified. These results supported the suggestion that the combined measurement of peripheral and brachial BP provides complementary information regarding physiological changes in NT and HT in different situations.

Hypertriglyceridaemia in mild hypertension: impact on cardiovascular and hormonal reactivity under different stress tests.

OBJECTIVES: We investigated the significance of hypertriglyceridaemia (HTG) for associated components of the metabolic syndrome and stress reactivity in subjects with mild hypertension. METHODS: Seventeen asymptomatic subjects with mild hypertension assessed by 24-h blood pressure (BP) measurement plus HTG (TG >2.3 mmol/l) were recruited and compared with age- and sex-matched subjects with hypertension alone and healthy controls. Cardiovascular and hormonal stress reactivity were tested in a standardised programme consisting of 6 min mental stress, 3 min finger grip and a submaximal bicycle ergometry. RESULTS: The hypertensive patients with HTG exhibited significantly higher fasting insulin, uric acid and gamma-GT levels and lower HDL-cholesterol. The cardiovascular reactivity was similar in all three tests with respect to brachial and peripheral BP in the groups. Peripheral BP during the tests was found to be higher particularly in subjects with hypertension alone. The correlations between BP parameters were disturbed in hypertensives with HTG. Latter group showed significantly higher dopamine, noradrenaline, as well as ACTH levels and an increased ACTH/cortisol ratio. CONCLUSION: HTG in mild hypertension is indicative for insulin resistance accompanied by a modified vascular reactivity as well as elevated catecholamines and ACTH.

Effects of different stress settings on cardiovascular parameters and their relationship to daily life blood pressure in normotensives, borderline hypertensives and hypertensives.

The aim of this study was to compare a traditional stress setting, consisting of two mental arithmetic tasks and two Stroop test modifications, and a stress setting of varying task demand and decision latitude according to Karasek's job strain model, with respect to their feasibility to elicit differences in cardiovascular reactivity and recovery in 20 normotensives, 20 borderline hypertensives, and 20 non-medicated hypertensives, carefully selected by means of World Health Organization criteria. In addition, the relationship between laboratory and everyday blood pressure was investigated. All subjects were tested under both stress settings in counterbalanced order. Blood pressure was recorded both intermittently from the brachial artery (Riva-Rocci) and continuously from the finger (Finapres). Heart rate and electrodermal activity were continuously measured as well. Furthermore, daily life blood pressure recorded by means of 24 h ambulatory monitoring during a normal working day served as criterion for the re-classification of the blood pressure groups by means of discriminant analysis using physiological recordings from baseline, test phases and rest phases. The groups did not show significant differences in their reactivity to the various mental stressors including the Karasek-model oriented ones but marked differences in their behaviour occurred during the 10 min of recovery following each stress setting. Both systolic and diastolic blood pressure in hypertensives failed to recover during this period. The results also showed the superiority of the Finapres method with respect to reflecting the dynamics of physiological recovery processes. None of the stress settings showed an advantage in predicting blood pressure in daily life. In general, the results question the validity of mental laboratory stressors for the prediction of cardiovascular changes in daily life but point to a possible role of recovery processes after stress in the development of essential hypertension.

Brachial and digital artery pulse pressures in hypertensive and normotensive subjects.

OBJECTIVES AND PATIENTS: To determine whether or not the pulsatile component of blood pressure (BP) measured centrally and peripherally allows a separation between hypertensive and normal subjects, as well as within hypertensive and normal subjects, as well as within hypertensive patients. We tested the hypothesis that the difference in central and peripheral pulse pressures is increased in hypertensive, compared to normotensive persons, and that this component is influenced by genetic variance. We studied 46 hypertensive patients and 56 age-matched normal subjects, as well as 10 hypertensive families with 74 members of the same age range. DESIGN: Pulse pressure was measured at the brachial artery and the digital artery in the standing and supine position. The difference in the pulse pressures between these sites was calculated. Further, digital volume-pulse amplitude and stroke volume measurements were determined with impedance plethysmography. RESULTS: The differences between central and peripheral pulse pressures were similar in hypertensive patients compared to normal subjects, regardless of posture. However, in the standing position the frequency distribution of this variable in hypertensive patients was bimodal and split into two significantly different distributions (P < 0.05) with peaks at -24 mm Hg and -1 mm Hg, compared to a single peak at -11 mm Hg in normal subjects. Furthermore, these two subgroups of hypertensive patients differed in their brachial systolic BP (127 +/- 10 vs 134 +/- 12 mm Hg; P < 0.05), their brachial pulse pressures (32 +/- 8 vs 42 +/- 8 mm Hg; P < 0.05), and in their peripheral compliance (1.59 +/- 0.92 vs 2.21 +/- 1.00 microliter/mm Hg per 100 ml tissue; P < 0.05). The frequency distribution of pulse pressure differences was also bimodal in members of hypertensive families, even though most (46 out of 74) were normotensive. CONCLUSION: The difference between the digital and brachial pulsatile component may be a useful intermediary phenotype in essential hypertension. Furthermore, the nonuniform decreases in arterial compliance exhibited by our patients may be of pathogenic significance.

Leukocyte responsiveness to substances that activate the respiratory burst is not altered in borderline and essential hypertension.

Activated leukocytes have been implicated in the pathogenesis of hypertension and its complications. The present study investigated the activity stage of leukocytes for production of reactive oxygen species (ROS) in 17 normotensive controls and subjects with borderline (n = 17) or essential hypertension (n = 17) using different biological materials (whole blood and isolated polymorphonuclear leukocytes (PMNLs)), stimuli (zymosan and formyl-methionyl-leucyl-phenylalanine (FMLP)) and ROS detection assays (chemiluminescence, hydrogen peroxide and superoxide anion determination). Neither the capacity for extracellular generation of oxygen metabolites nor the production of ROS with an intracellular origin were significantly different in isolated PMNLs between controls and hypertensive subjects. There were no significant differences in the luminol-amplified zymosan- or FMLP-stimulated whole blood chemiluminescence response. In addition, the leukocyte count did not differ between the groups. The results suggest that circulating leukocytes of controls and hypertensives existed in a resting state in our experimental conditions. We did not find any evidence of enhanced basal leukocyte free radical activity in patients with mild or severe hypertension.