The permanently open auditory channel and the ability of the brain to process incoming acoustical... more The permanently open auditory channel and the ability of the brain to process incoming acoustical stimuli even while asleep and to respond adequately is the essential precondition for noise-induced sleep disturbances which are regarded as the most deleterious effects of noise. In the past, research was mainly focused on the detection and description of the various effects of noise, on the influence of personal and environmental factors, on the determination of dose-response relations and the definition of critical noise loads, above which noise becomes intolerable. These limits are, however, as yet only tentative or applicable for a very few situations and need to be verified or revised. The present paper is focused on the priorities for future research. These are in particular 1) the causal linkage between environmental noise, primary and secondary effects on the one hand and the hypothesized contribution to multifactorial chronic diseases, to chronic annoyance, and to permanent be...
P of 258 W/m2 that decreased to 114 W/m2. The exposure was arranged in two 30-min work periods (4... more P of 258 W/m2 that decreased to 114 W/m2. The exposure was arranged in two 30-min work periods (4 km/h on a level) interrupted by a 3-min pause for weighing, preceded by a 30-min rest and followed by a 30-min recovery in a neutral climate. The minimum time interval between the experiments for each subject was at least one day.
Polysomnography is the gold standard for investigating noise effects on sleep, but data collectio... more Polysomnography is the gold standard for investigating noise effects on sleep, but data collection and analysis are sumptuous and expensive. We recently developed an algorithm for the automatic identification of cardiac activations associated with cortical arousals, which uses heart rate information derived from a single electrocardiogram (ECG) channel. We hypothesized that cardiac activations can be used as estimates for EEG awakenings. Polysomnographic EEG awakenings and automatically detected cardiac activations were systematically compared using laboratory data of 112 subjects (47 male, mean+/-SD age 37.9+/-13 years), 985 nights and 23,855 aircraft noise events (ANEs). The probability of automatically detected cardiac activations increased monotonically with increasing maximum sound pressure levels of ANEs, exceeding the probability of EEG awakenings by up to 18.1%. If spontaneous reactions were taken into account, exposure-response curves were practically identical for EEG awakenings and cardiac activations. Automatically detected cardiac activations may be used as estimates for EEG awakenings. More investigations are needed to further validate the ECG algorithm in the field and to investigate inter-individual differences in its ability to predict EEG awakenings. This inexpensive, objective and non-invasive method facilitates large-scale field studies on the effects of traffic noise on sleep.
Cortisol awakening response (CAR), a considerable increase in cortisol concentrations post-awaken... more Cortisol awakening response (CAR), a considerable increase in cortisol concentrations post-awakening, is considered a reliable indicator of the reactivity of the hypothalamus-pituitary-adrenal axis (HPA). As noise has been shown to activate the HPA-axis, this analysis focuses on CAR as a possible indicator of noise-induced sleep disturbances. This analysis focuses on CAR using two studies. In Study 1, six women and six men (18-26 years) slept for 13 nights each in the laboratory. They were exposed to the noises of three different trains, each with 20, 40 or 80 pass-bys, with equivalent noise levels varying between 44 and 58 dBA, on nine nights. In Study 2, 23 persons slept first for four nights and then four days, in the laboratory; finally 23 persons slept in the reverse order. During six sleep periods, they were randomly exposed to road or rail traffic noises with L Aeq varying between 42 and 56 dBA. To determine the CAR, salivary cortisol concentrations were ascertained in both studies after night sleep immediately after awakening, and 15 and 45 minutes later; in Study 2 also after 30 and 60 minutes later. The time of awakening was determined using the polysomnogram and the participants rated their subjective sleep quality every morning. Subjective sleep quality was rated worse after noisy when compared to quiet nights. CAR was, however, attenuated only after the noisiest nights in a subgroup of Study 2. These persons had just performed a sequence of four consecutive night shifts. They were obviously still in the process of re-adjustment to their usual day-oriented schedule and probably in a state of elevated vulnerability. The study concludes that nocturnal noise exposure affects the CAR only if a person is in a state of at least temporarily elevated vulnerability.
... stronger reactions to the highest noise load. Aircraft noise, rail and road traffic noise cau... more ... stronger reactions to the highest noise load. Aircraft noise, rail and road traffic noise caused similar after-effects but physiological sleep parameters were most severely affected by rail noise. The equivalent noise level seems to be ...
Cross-sectional data on urinary 6-hydroxymelatonin sulfate (6-OHMS) excretion in children suggest... more Cross-sectional data on urinary 6-hydroxymelatonin sulfate (6-OHMS) excretion in children suggest a constant melatonin secretion during growth. The present longitudinal study concerned, accordingly, the intra-individual stability of melatonin production during childhood and adolescence. Urine samples collected during a longitudinal investigation of healthy white children and adolescents were analyzed. Forty-six boys and 38 girls were chosen for the present study. They had passed 3-15 annual examinations between their 3rd and 18th yr of age. Each examination included the collection of urine over 24 hr. The daily urinary output of 6-OHMS of the overall 621 samples was quantified by enzyme-linked immunosorbent assay. The analyses clearly revealed for the first time that, despite huge inter-individual differences, melatonin production remains constant in one and the same individual during childhood and adolescence. Additionally, neither a significant sex difference was observed nor was the 6-OHMS output affected by season. The dramatic decrease of plasma melatonin levels as described in the literature is mainly related to an increase in body size rather than to decreasing pineal secretion.
Cortisol awakening responses (CAR) are often blunted or even extinguished when saliva samplings a... more Cortisol awakening responses (CAR) are often blunted or even extinguished when saliva samplings are delayed. The literature suggests that delays of 10 or 15 min are tolerable. Delays of 15 min were analysed with 510 CARs with the first sample taken within 3 min post-awakening followed by 4 samples taken 15, 30, 45, and 60 min later. Varying delays of up to 30 min were analysed with these and further 148 CARs where sampling began within 30 min post-awakening. Times of awakening and of saliva collection were verified by polysomnography or actimetry and by electronic devices respectively. Simulated sampling delays of 15 min revealed highly significant deviations from correctly taken CARs. No deviations were found for delays of up to 11.5 min suggesting that delays of up to 10 min are acceptable but that delays between 10 and 15 min might become critical.
International Archives of Occupational and Environmental Health, 2002
To co-ordinate the work of the main European research teams in the field of thermal factors in or... more To co-ordinate the work of the main European research teams in the field of thermal factors in order to develop and improve significantly the methods presently available for assessing the risks of heat disorders encountered during work in hot conditions. Each item from the required sweat rate model was reviewed on the basis of the most recent literature. A database with 1,113 laboratory and field experiments, covering the whole range of hot working conditions, was assembled and used for the validation. Influence of clothing ensemble on heat exchange: methods and formulas were developed that take into account the dynamic effects associated with forced convection and the pumping effect associated with body movements and exercise. Prediction of the average skin temperature: the model used in the required sweat rate standard ISO 7933 was extended to cover more severe conditions with high radiation and high humidity and different clothing and take into account the rectal temperature for the prediction of the skin temperature. Criteria for estimating acceptable exposure times in hot work environments: criteria were reviewed and updated concerning the maximum increase in core temperature and the acceptable water loss, for acclimatised and nonacclimatised subjects. These limits are intended to protect 95% of the population. Measuring strategy: a strategy was developed to assess the risks in any working situation with varying conditions of climate, metabolic rate or clothing. A detailed methodology was developed in three stages: an "observation" method for the recognition of the conditions that might lead to thermal stress; an "analysis" method for evaluating the problem and optimising the solutions; and an "expert" method for in-depth analysis of the working situation when needed. the different results were used to prepare a revision of the interpretation procedure proposed in the ISO standard 7933. We validated the modified approaches using the database. This involved the whole range of conditions for which the model was extended, namely conditions with high and low radiation, humidity and air velocity as well as fluctuating conditions. Based on these results, the predicted heat strain model was developed: it is presently proposed as an ISO and CEN standard.
International Archives of Occupational and Environmental Health, 2009
There is no information of mental strain in noise sensitive persons working under moderate levels... more There is no information of mental strain in noise sensitive persons working under moderate levels of noise. The aim of the study was to determine relevant dimensions of impairing effects differentiating between noise sensitive and insensitive persons. 56 participants (27 men, 29 women; 18-31 years old) were classified into 28 low and 28 high noise sensitive persons. They worked either on a grammatical reasoning task (GRT) or a mental arithmetic task (MPT) under realistic road traffic scenarios [LAeq 55 dB(A)]. Afterwards they rated their annoyance and subjective mental strain. A multivariate analysis of variance provided significant effects for the individual noise sensitivity (P < 0.01) and the kind of task being performed (P < 0.01). To determine to what extent the rating scales lead to a differentiation of the four groups, a 2-factorial discriminant analysis was carried out subsequently. Results showed, that psycho-physiological effort and emotional strain differentiated best between the noise sensitivity groups and psycho physiological effort and focus on tasks (attention) separated the tasks. Noise sensitive persons are more distracted by noise than insensitive persons. Furthermore the results suggest that noise sensitive subjects do not only evaluate a noisy situation as more annoying but experience higher levels of strain than insensitive persons.
This paper concerns the influence of air temperature and of the direction of drafts on subjective... more This paper concerns the influence of air temperature and of the direction of drafts on subjective and physiological responses. In three experimental series 58 healthy persons (50 men, 8 women, 20-29 yrs) were exposed to drafts in overall 446 experimental sessions. Drafts were applied either horizontally or vertically with mean air velocities of 0.1 to 0.3 m/s and a turbulence
The permanently open auditory channel and the ability of the brain to process incoming acoustical... more The permanently open auditory channel and the ability of the brain to process incoming acoustical stimuli even while asleep and to respond adequately is the essential precondition for noise-induced sleep disturbances which are regarded as the most deleterious effects of noise. In the past, research was mainly focused on the detection and description of the various effects of noise, on the influence of personal and environmental factors, on the determination of dose-response relations and the definition of critical noise loads, above which noise becomes intolerable. These limits are, however, as yet only tentative or applicable for a very few situations and need to be verified or revised. The present paper is focused on the priorities for future research. These are in particular 1) the causal linkage between environmental noise, primary and secondary effects on the one hand and the hypothesized contribution to multifactorial chronic diseases, to chronic annoyance, and to permanent be...
P of 258 W/m2 that decreased to 114 W/m2. The exposure was arranged in two 30-min work periods (4... more P of 258 W/m2 that decreased to 114 W/m2. The exposure was arranged in two 30-min work periods (4 km/h on a level) interrupted by a 3-min pause for weighing, preceded by a 30-min rest and followed by a 30-min recovery in a neutral climate. The minimum time interval between the experiments for each subject was at least one day.
Polysomnography is the gold standard for investigating noise effects on sleep, but data collectio... more Polysomnography is the gold standard for investigating noise effects on sleep, but data collection and analysis are sumptuous and expensive. We recently developed an algorithm for the automatic identification of cardiac activations associated with cortical arousals, which uses heart rate information derived from a single electrocardiogram (ECG) channel. We hypothesized that cardiac activations can be used as estimates for EEG awakenings. Polysomnographic EEG awakenings and automatically detected cardiac activations were systematically compared using laboratory data of 112 subjects (47 male, mean+/-SD age 37.9+/-13 years), 985 nights and 23,855 aircraft noise events (ANEs). The probability of automatically detected cardiac activations increased monotonically with increasing maximum sound pressure levels of ANEs, exceeding the probability of EEG awakenings by up to 18.1%. If spontaneous reactions were taken into account, exposure-response curves were practically identical for EEG awakenings and cardiac activations. Automatically detected cardiac activations may be used as estimates for EEG awakenings. More investigations are needed to further validate the ECG algorithm in the field and to investigate inter-individual differences in its ability to predict EEG awakenings. This inexpensive, objective and non-invasive method facilitates large-scale field studies on the effects of traffic noise on sleep.
Cortisol awakening response (CAR), a considerable increase in cortisol concentrations post-awaken... more Cortisol awakening response (CAR), a considerable increase in cortisol concentrations post-awakening, is considered a reliable indicator of the reactivity of the hypothalamus-pituitary-adrenal axis (HPA). As noise has been shown to activate the HPA-axis, this analysis focuses on CAR as a possible indicator of noise-induced sleep disturbances. This analysis focuses on CAR using two studies. In Study 1, six women and six men (18-26 years) slept for 13 nights each in the laboratory. They were exposed to the noises of three different trains, each with 20, 40 or 80 pass-bys, with equivalent noise levels varying between 44 and 58 dBA, on nine nights. In Study 2, 23 persons slept first for four nights and then four days, in the laboratory; finally 23 persons slept in the reverse order. During six sleep periods, they were randomly exposed to road or rail traffic noises with L Aeq varying between 42 and 56 dBA. To determine the CAR, salivary cortisol concentrations were ascertained in both studies after night sleep immediately after awakening, and 15 and 45 minutes later; in Study 2 also after 30 and 60 minutes later. The time of awakening was determined using the polysomnogram and the participants rated their subjective sleep quality every morning. Subjective sleep quality was rated worse after noisy when compared to quiet nights. CAR was, however, attenuated only after the noisiest nights in a subgroup of Study 2. These persons had just performed a sequence of four consecutive night shifts. They were obviously still in the process of re-adjustment to their usual day-oriented schedule and probably in a state of elevated vulnerability. The study concludes that nocturnal noise exposure affects the CAR only if a person is in a state of at least temporarily elevated vulnerability.
... stronger reactions to the highest noise load. Aircraft noise, rail and road traffic noise cau... more ... stronger reactions to the highest noise load. Aircraft noise, rail and road traffic noise caused similar after-effects but physiological sleep parameters were most severely affected by rail noise. The equivalent noise level seems to be ...
Cross-sectional data on urinary 6-hydroxymelatonin sulfate (6-OHMS) excretion in children suggest... more Cross-sectional data on urinary 6-hydroxymelatonin sulfate (6-OHMS) excretion in children suggest a constant melatonin secretion during growth. The present longitudinal study concerned, accordingly, the intra-individual stability of melatonin production during childhood and adolescence. Urine samples collected during a longitudinal investigation of healthy white children and adolescents were analyzed. Forty-six boys and 38 girls were chosen for the present study. They had passed 3-15 annual examinations between their 3rd and 18th yr of age. Each examination included the collection of urine over 24 hr. The daily urinary output of 6-OHMS of the overall 621 samples was quantified by enzyme-linked immunosorbent assay. The analyses clearly revealed for the first time that, despite huge inter-individual differences, melatonin production remains constant in one and the same individual during childhood and adolescence. Additionally, neither a significant sex difference was observed nor was the 6-OHMS output affected by season. The dramatic decrease of plasma melatonin levels as described in the literature is mainly related to an increase in body size rather than to decreasing pineal secretion.
Cortisol awakening responses (CAR) are often blunted or even extinguished when saliva samplings a... more Cortisol awakening responses (CAR) are often blunted or even extinguished when saliva samplings are delayed. The literature suggests that delays of 10 or 15 min are tolerable. Delays of 15 min were analysed with 510 CARs with the first sample taken within 3 min post-awakening followed by 4 samples taken 15, 30, 45, and 60 min later. Varying delays of up to 30 min were analysed with these and further 148 CARs where sampling began within 30 min post-awakening. Times of awakening and of saliva collection were verified by polysomnography or actimetry and by electronic devices respectively. Simulated sampling delays of 15 min revealed highly significant deviations from correctly taken CARs. No deviations were found for delays of up to 11.5 min suggesting that delays of up to 10 min are acceptable but that delays between 10 and 15 min might become critical.
International Archives of Occupational and Environmental Health, 2002
To co-ordinate the work of the main European research teams in the field of thermal factors in or... more To co-ordinate the work of the main European research teams in the field of thermal factors in order to develop and improve significantly the methods presently available for assessing the risks of heat disorders encountered during work in hot conditions. Each item from the required sweat rate model was reviewed on the basis of the most recent literature. A database with 1,113 laboratory and field experiments, covering the whole range of hot working conditions, was assembled and used for the validation. Influence of clothing ensemble on heat exchange: methods and formulas were developed that take into account the dynamic effects associated with forced convection and the pumping effect associated with body movements and exercise. Prediction of the average skin temperature: the model used in the required sweat rate standard ISO 7933 was extended to cover more severe conditions with high radiation and high humidity and different clothing and take into account the rectal temperature for the prediction of the skin temperature. Criteria for estimating acceptable exposure times in hot work environments: criteria were reviewed and updated concerning the maximum increase in core temperature and the acceptable water loss, for acclimatised and nonacclimatised subjects. These limits are intended to protect 95% of the population. Measuring strategy: a strategy was developed to assess the risks in any working situation with varying conditions of climate, metabolic rate or clothing. A detailed methodology was developed in three stages: an "observation" method for the recognition of the conditions that might lead to thermal stress; an "analysis" method for evaluating the problem and optimising the solutions; and an "expert" method for in-depth analysis of the working situation when needed. the different results were used to prepare a revision of the interpretation procedure proposed in the ISO standard 7933. We validated the modified approaches using the database. This involved the whole range of conditions for which the model was extended, namely conditions with high and low radiation, humidity and air velocity as well as fluctuating conditions. Based on these results, the predicted heat strain model was developed: it is presently proposed as an ISO and CEN standard.
International Archives of Occupational and Environmental Health, 2009
There is no information of mental strain in noise sensitive persons working under moderate levels... more There is no information of mental strain in noise sensitive persons working under moderate levels of noise. The aim of the study was to determine relevant dimensions of impairing effects differentiating between noise sensitive and insensitive persons. 56 participants (27 men, 29 women; 18-31 years old) were classified into 28 low and 28 high noise sensitive persons. They worked either on a grammatical reasoning task (GRT) or a mental arithmetic task (MPT) under realistic road traffic scenarios [LAeq 55 dB(A)]. Afterwards they rated their annoyance and subjective mental strain. A multivariate analysis of variance provided significant effects for the individual noise sensitivity (P < 0.01) and the kind of task being performed (P < 0.01). To determine to what extent the rating scales lead to a differentiation of the four groups, a 2-factorial discriminant analysis was carried out subsequently. Results showed, that psycho-physiological effort and emotional strain differentiated best between the noise sensitivity groups and psycho physiological effort and focus on tasks (attention) separated the tasks. Noise sensitive persons are more distracted by noise than insensitive persons. Furthermore the results suggest that noise sensitive subjects do not only evaluate a noisy situation as more annoying but experience higher levels of strain than insensitive persons.
This paper concerns the influence of air temperature and of the direction of drafts on subjective... more This paper concerns the influence of air temperature and of the direction of drafts on subjective and physiological responses. In three experimental series 58 healthy persons (50 men, 8 women, 20-29 yrs) were exposed to drafts in overall 446 experimental sessions. Drafts were applied either horizontally or vertically with mean air velocities of 0.1 to 0.3 m/s and a turbulence
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Papers by Barbara Griefahn