Urinary and salivary stress hormone levels while performing arithmetic calculation in a noisy environment

Psychophysiological effects of walking in forests and urban built environments with disparate road traffic noise exposure: study protocol of a randomized controlled trial

BACKGROUND

Stress is a widespread phenomenon and reality of everyday life, entailing negative consequences for physical and psychological wellbeing. Previous studies have indicated that exposure to greenspaces and nature-based interventions are promising approaches to reducing stress and promoting restoration. However, an increasing percentage of the population lives in urban regions with limited opportunities to spend time in greenspaces. In addition, urban settings typically feature increased levels of noise, which represents a major environmental stressor. Although various studies have compared the effects of exposure to greenspaces versus urban built environments, evidence of the effects of noise in this context is very limited. Psychophysiological benefits of exposure to greenspaces compared to urban built environments reported in earlier studies might be less (or at least not only) due to features of the greenspaces than to additional stressors, such as road traffic noise in the urban built environment. Hence, differences in the effects attributed to greenness in previous studies may also be due to potentially detrimental noise effects in comparison settings. This paper reports the study protocol for a randomized, controlled intervention study comparing the effects of walking in forest versus urban built environments, taking road traffic noise exposure during walks in the respective settings into account.

METHODS

The protocol envisages a field study employing a pretest-posttest design to compare the effects of 30-min walks in urban built environments and forests with different road traffic noise levels. Assessments will consist of self-reported measures, physiological data (salivary cortisol and skin conductance), an attention test, and noise, as well as greenness measurements. The outcomes will be restoration, stress, positive and negative affect, attention, rumination, and nature connectedness.

DISCUSSION

The results will inform about the restorative effect of walking in general, of exposure to different types of environments, and to different noise levels in these sites. The study will provide insights into the benefits of walking and nature-based interventions, taking into account the potential detrimental effects of noise exposure. It will thus facilitate a better understanding of low-threshold interventions to prevent stress and foster wellbeing.

TRIAL REGISTRATION

ISRCTN48943261 ; Registered 23.11.2023.

Mental calculation increases physiological postural tremor, but does not influence physiological goal-directed kinetic tremor

Purpose

During a cognitive effort, an increase in cortical electrical activity, functional alterations in the anterior cingulate cortex, and modifications in cortical inputs to the active motor units have been reported. In light of this, an increase in tremor could be anticipated as result of a mental task. In the present work, we tested this hypothesis.

Methods

In 25 individuals, tremor was measured with a three-axial accelerometer during 300 s of postural and goal-directed tasks performed simultaneously to mental calculation, or during control (same tasks without mental calculation). Hand and finger dexterity were also evaluated. Electromyographic (EMG) recordings from the extensor digitorum communis were collected during the postural task.

Results

Hand and finger dexterity was negatively affected by the mental task (p = .003 and p = .00005 respectively). During mental calculation, muscle tremor increased in the hand postural (+ 29%, p = .00005) but not in the goal-directed task (− 1.5%, p > .05). The amplitude of the main frequency peak also increased exclusively in the hand postural task (p = .028), whilst no shift in the position of the main frequency peak was observed. EMG was not affected.

Conclusion

These results support the position of the contribution of a central component in the origin of physiological hand postural tremor. It is suggested that the different effect of mental calculation on hand postural and goal-directed tasks can be attributed to the different origins and characteristics of hand postural and goal-directed physiological tremor.

Speech is special: The stress effects of speech, noise, and silence during tasks requiring concentration

Effects of noise on people depend on sound level but also on other sound properties. A systematic comparison of the stress effects of speech and noise with the same frequency content is missing. This study compared stress reactions under sound conditions speech (sound level 65 dB L_Aeq ), noise (65 dB), and silence (35 dB), all having similar relative frequency contents. Fifty-nine participants were exposed to one out of three sound conditions on average for 48 minutes while performing tasks requiring concentration. Acute physiological stress was estimated by measuring stress hormone concentrations in plasma (cortisol and noradrenaline), heart rate variability (HRV), and blood pressure. Psychological stress measures were subjective noise annoyance, workload, and fatigue. Compared to silence and noise, working during speech was more annoying, loading, but less tiring, and led to elevated HRV LF/HF ratio with time. Speech also raised cortisol levels compared with silence. Although noise was more annoying, and raised cortisol levels compared with silence, working during speech was more loading and caused more physiological stress than other sound conditions. Special care should be paid to noise control in workplaces requiring concentration because already exposure to moderate sound level sounds caused clear physiological effects on people.

Noise exposure among teachers in technology educational shops in selected British Columbia, Canada, high schools

Teachers in technology education shops (TESs) in high schools are at risk from exposure to occupational hazards, including physical work demands and chemicals, particulate matter and noise, as well as non-optimal working conditions negatively affected by temperature, humidity, and lighting. This study evaluated the exposure to noise of 17 TES teachers working in 17 wood-working, metal-working, and automotive shops in selected high schools in British Columbia, Canada, and examined the quality of the acoustical teaching environments due to background noise. This study characterized noise control measures in the sampled TESs and observed the safety practices of teachers during TES classes. The results of this investigation indicated that almost 60% of the participating teachers were exposed to unacceptable levels of noise during teaching and working in TESs. It also showed that TES acoustical environmental quality was adversely affected by high background noise levels due to poor room designs and settings. Practical recommendations were provided to reduce and control the exposure to noise in TESs and to enhance the quality of health, safety, and quality of teaching environment in these TESs.

The responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact sound: a pilot study

BACKGROUND

Recently, noise coming from the neighborhood via floor wall has become a great social problem. The noise between the floors can be a cause of physical and psychological problems, and the different types of floor impact sound (FIS) may have the different effects on the human's body and mind. The purpose of this study is to assess the responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact.

METHODS

Ten men and 5 women were enrolled in our study, and the English listening test was performed under the twelve different types of FIS, which were made by the combinations of bang machine (B), tapping machine (T), impact ball (I) and sound-proof mattress (M). The 15 subjects were exposed to each FIS for about 3 min, and the subjective annoyance, performance ability (English listening test), cortisol level of urine/saliva and heart rate variability (HRV) were examined. The sound pressure level (SPL) and frequency of FIS were analyzed. Repeated-measures ANOVA, paired t-test, Wilcoxon signed rank test were performed for data analysis.

RESULTS

The SPL of tapping machine (T) was reduced with the soundproof mattress (M) by 3.9-7.3 dBA. Impact ball (I) was higher than other FIS in low frequency (31.5-125 Hz) by 10 dBA, and tapping machine (T) was higher than other FIS in high frequency (2-4 k Hz) by 10 dBA. The subjective annoyance is highest in the combination of bang machine and tapping machine (BT), and next in the tapping machine (T). The English listening score was also lowest in the BT, and next in T. The difference of salivary cortisol levels between various types of FIS was significant (p = 0.003). The change of HRV parameters by the change of FIS types was significant in some parameters, which were total power (TP) (p = 0.004), low frequency (LF) (p = 0.002) and high frequency (HF) (p = 0.011).

CONCLUSIONS

These results suggest that the human's subjective and objective responses were different according to FIS types and those combinations.

Road traffic noise effects on cardiovascular, respiratory, and metabolic health: An integrative model of biological mechanisms

BACKGROUND

Road traffic noise is a major public health issue, given the documented association with several diseases and the growing number of exposed persons all over the world. The effects widely investigated pertain to cardiovascular health, and to a lesser extent to respiratory and metabolic health. The epidemiological design of most studies has made it possible to ascertain long-term associations of urban noise with a number of cardiovascular, respiratory, and metabolic disorders and diseases; additionally, time series studies have reported short-term associations.

OBJECTIVES

To review the various biological mechanisms that may account for all long-term as well as short-term associations between road traffic noise and cardiovascular, respiratory, and metabolic health. We also aimed to review the neuroendocrine processes triggered by noise as a stressor and the role of the central nervous system in noise-induced autonomic responses.

METHODS

Review of the literature on road traffic noise, environmental noise in general, psychosomatics, and diseases of the cardiovascular, respiratory, and metabolic systems. The search was done using PubMed databases.

DISCUSSION

We present a comprehensive, integrative stress model with all known connections between the body systems, states, and processes at both the physiological and psychological levels, which allows to establish a variety of biological pathways linking environmental noise exposure with health outcomes.

CONCLUSIONS

The long- and short-term associations between road traffic noise and health outcomes found in latest noise research may be understood in the light of the integrative model proposed here.

The Association between Noise, Cortisol and Heart Rate in a Small-Scale Gold Mining Community-A Pilot Study

We performed a cross-sectional pilot study on salivary cortisol, heart rate, and personal noise exposures in a small-scale gold mining village in northeastern Ghana in 2013. Cortisol level changes between morning and evening among participants showed a relatively low decline in cortisol through the day (−1.44 ± 4.27 nmol/L, n = 18), a pattern consistent with chronic stress. A multiple linear regression, adjusting for age, sex, smoking status, and time between samples indicated a significant increase of 0.25 nmol/L cortisol from afternoon to evening per 1 dBA increase in equivalent continuous noise exposure (L_eq) over that period (95% CI: 0.08–0.42, Adj R² = 0.502, n = 17). A mixed effect linear regression model adjusting for age and sex indicated a significant increase of 0.29 heart beats per minute (BPM) for every 1 dB increase in L_eq. Using standard deviations (SDs) as measures of variation, and adjusting for age and sex over the sampling period, we found that a 1 dBA increase in noise variation over time (L_eq SD) was associated with a 0.5 BPM increase in heart rate SD (95% CI: 0.04–−0.9, Adj. R² = 0.229, n = 16). Noise levels were consistently high, with 24-hour average L_eq exposures ranging from 56.9 to 92.0 dBA, with a mean daily L_eq of 82.2 ± 7.3 dBA (mean monitoring duration 22.1 ± 1.9 hours, n = 22). Ninety-five percent of participants had 24-hour average L_eq noise levels over the 70 dBA World health Organization (WHO) guideline level for prevention of hearing loss. These findings suggest that small-scale mining communities may face multiple, potentially additive health risks that are not yet well documented, including hearing loss and cardiovascular effects of stress and noise.

Professional exposure to urban stressors and effects on urinary metanephrines

The aim of the study is to assess whether occupational exposure to urban stressors could cause alterations in urinary metanephrines levels in traffic policemen vs administrative staff of municipal police. A total of 258 subjects were included in the study: 129 traffic policemen exposed to urban stressors (68 males and 61 females) and 129 controls (68 males and 61 females). Urinary metanephrines mean levels were significantly higher in male traffic policemen compared to controls (p < 0.01). No significant differences were in female traffic policemen compared to controls. In the control group, urinary metanephrines mean levels were significantly higher in females compared to males (p < 0.01). There were no significant differences in urinary metanephrines mean levels in female traffic policemen vs male traffic policemen. The increase in urinary metanephrines mean levels observed in male exposed compared to controls could be related to chronic occupational exposure to low doses of chemical, physical and psychosocial urban stressors.

Saliva cortisol and exposure to aircraft noise in six European countries

BACKGROUND

Several studies show an association between exposure to aircraft or road traffic noise and cardiovascular effects, which may be mediated by a noise-induced release of stress hormones.

OBJECTIVE

Our objective was to assess saliva cortisol concentration in relation to exposure to aircraft noise.

METHOD

A multicenter cross-sectional study, HYENA (Hypertension and Exposure to Noise near Airports), comprising 4,861 persons was carried out in six European countries. In a subgroup of 439 study participants, selected to enhance the contrast in exposure to aircraft noise, saliva cortisol was assessed three times (morning, lunch, and evening) during 1 day.

RESULTS

We observed an elevation of 6.07 nmol/L [95% confidence interval (CI), 2.32-9.81 nmol/L] in morning saliva cortisol level in women exposed to aircraft noise at an average 24-hr sound level (L(Aeq,24h)) > 60 dB, compared with women exposed to L(Aeq,24h) < or = 50 dB, corresponding to an increase of 34%. Employment status appeared to modify the response. We found no association between noise exposure and saliva cortisol levels in men.

CONCLUSIONS

Our results suggest that exposure to aircraft noise increases morning saliva cortisol levels in women, which could be of relevance for noise-related cardiovascular effects.

Influence of Chewing and Clenching on Salivary Cortisol Levels as an Indicator of Stress

PURPOSE

The purpose of this study was to investigate the effects of chewing and clenching on salivary cortisol levels as an indicator of stress.

MATERIALS AND METHODS

Seventeen healthy dentulous subjects were given arithmetic exercises to perform within a 20-minute time limit in order to elicit stress (stress loading). In the first experiment (chewing), after stress loading, the subjects were asked to chew a paraffin wax while reading printed material (books, magazines, etc.) in silence for 10 minutes. The same procedure was then carried out again for control purposes, but this time the subjects were not required to chew wax. In the second experiment (light clenching), after stress loading, the subjects were required to carry out 5 seconds of light clenching followed by 5 seconds of rest repeatedly over a 3-minute period. The whole 3-minute process was repeated a total of three times. The control data for this second experiment consisted of measurements taken during the rest periods. Saliva specimens were collected in both experiments both before stress loading and after each procedure during 1-minute intervals to measure cortisol levels.

RESULTS

In the chewing experiment, salivary cortisol levels were significantly reduced by chewing, compared with those in the controls (p < 0.05). This reduction in salivary cortisol was observed during chewing over a 10-minute period following stress loading. In the clenching experiment, salivary cortisol levels also showed a significant reduction during clenching, compared with those in the controls (p < 0.05).

CONCLUSIONS

These results suggest that chewing and clenching promote relaxation in subjects under stress.

Saliva cortisol--a new approach in noise research to study stress effects

Several studies have indicated an association between noise exposure and cardiovascular disease. A noise-induced release of stress hormones has been considered to be a biological pathway of importance in this respect. The described method is of special interest since concentration of cortisol in saliva reflects the concentration of free cortisol in serum and repeated saliva samples can easily be collected. Our objective is to overview the use of saliva cortisol to measure stress in relation to noise as a tool for research on noise-related cardiovascular risk. Previous studies of saliva cortisol in relation to noise exposure are reviewed. In summary, repeated assessments of saliva cortisol seems to be a feasible method to apply in field studies in noise research.

Chronoecoepidemiology of "strain": infradian chronomics of urinary cortisol and catecholamines during nightly exposure to noise

This meta-analysis of published data (Noise Health 5 (2002) 35 and 47) summarizing a survey for 40 days of the nightly excretion of urinary free cortisol, epinephrine and norepinephrine validates a circaseptan cortisol pattern anticipated and reported earlier for cortisol, here not detected for the catecholamines. We also quantify a circadecan (about 10-day) variation in nightly norepinephrine excretion, but not in the excretion of the other two hormones examined. About 4.2-day variations, common to norepinephrine and epinephrine, and an about 4.7-day variation in cortisol await further scrutiny, since these components were not anticipated. Infradian characteristics are quantified time-microscopically and differences among infradian aspects of the spectral element of endocrine chronomes (time structures; from chronos, time and nomos, rule) are demonstrated. Chronomics, the cartography of chronomes, reveals that "stress hormones" need to be examined separately in a budding chronoepidemiology seeking to detect how humans interact, mostly for better, sometimes for worse, with the undesirable features of the technology they create and of its consequences, such as aircraft noise.

Acute stressors and cortisol responses: a theoretical integration and synthesis of laboratory research

This meta-analysis reviews 208 laboratory studies of acute psychological stressors and tests a theoretical model delineating conditions capable of eliciting cortisol responses. Psychological stressors increased cortisol levels; however, effects varied widely across tasks. Consistent with the theoretical model, motivated performance tasks elicited cortisol responses if they were uncontrollable or characterized by social-evaluative threat (task performance could be negatively judged by others), when methodological factors and other stressor characteristics were controlled for. Tasks containing both uncontrollable and social-evaluative elements were associated with the largest cortisol and adrenocorticotropin hormone changes and the longest times to recovery. These findings are consistent with the animal literature on the physiological effects of uncontrollable social threat and contradict the belief that cortisol is responsive to all types of stressors.

A physiological correlate for the intolerance to both internal and external sounds

The notion that stress can induce chronic tinnitus, or increase its intensity, is predominant in the literature on tinnitus. However, there is little empirical support for this claim, since previous studies rely merely on subjective reports. In the present study, we used an objective physiological measure of stress (i.e., basal secretion of the stress hormone cortisol), in order to assess the relationship between tinnitus and stress. We hypothesized that tinnitus, a permanent internal sound, should behave as a stressor and should be accompanied by chronically elevated cortisol levels in individuals with severe tinnitus. In addition, we hypothesized that suffering from severe tinnitus should generalize to an intolerance towards external sounds. Two groups each comprised of 18 participants (with and without tinnitus) matched on education and health status participated in the study. Tinnitus severity, as assessed by tinnitus-related distress, was high in half of the tinnitus participants, and low in the other half. Basal cortisol levels were measured using saliva samples (five saliva samples per day for 3 days within a week) taken in the participant's natural environment. Intolerance to external sounds was assessed psychometrically. The high tinnitus-related distress group had chronic cortisol levels greater than both the low tinnitus-related distress and control groups, and also displayed greater intolerance to external sounds. The low tinnitus-related distress and control groups did not differ from each other on either of these measures. Our study thus provides the first physiological and empirical evidence of a link between intolerance to both internal (tinnitus) and external sounds in persons with tinnitus, and is compatible with the clinical observation that severe tinnitus is associated with high stress levels.

Noise, stress, and annoyance in a pediatric intensive care unit

OBJECTIVE

To measure and describe hospital noise and determine whether noise can be correlated with nursing stress measured by questionnaire, salivary amylase, and heart rate.

DESIGN

Cohort observational study.

SETTING

Tertiary care center pediatric intensive care unit.

SUBJECTS

Registered nurses working in the unit.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eleven nurse volunteers were recruited. An audiogram, questionnaire data, salivary amylase, and heart rate were collected in a quiet room. Each nurse was observed for a 3-hr period during patient care. Heart rate and sound level were recorded continuously; saliva samples and stress/annoyance ratings were collected every 30 mins. Variables assessed as potential confounders were years of nursing experience, caffeine intake, patients' Pediatric Risk of Mortality Score, shift assignment, and room assignment. Data were analyzed by random effects multiple linear regression using Stata 6.0. The average daytime sound level was 61 dB(A), nighttime 59 dB(A). Higher average sound levels significantly predicted higher heart rates (p =.014). Other significant predictors of tachycardia were higher caffeine intake, less nursing experience, and daytime shift. Ninety percent of the variability in heart rate was explained by the regression equation. Amylase measurements showed a large variability and were not significantly affected by noise levels. Higher average sound levels were also predictive of greater subjective stress (p =.021) and annoyance (p =.016).

CONCLUSIONS

In this small study, noise was shown to correlate with several measures of stress including tachycardia and annoyance ratings. Further studies of interventions to reduce noise are essential.

Combined effects of working environmental conditions in VDT work

The combined effects of city noise and luminance of the computer display were evaluated from the changes in lymphocytes and mental activities of participants. Healthy male students were tested under the following four experimental conditions: (1) a calculating task on a video display terminal (VDT) with luminance of 90 cd m(-2) without city noise; (2) a calculating task on a VDT with luminance of 20 cd m(-2) without city noise; (3) a calculating task on a VDT with luminance of 90 cd m(-2) with city noise of 70 dB(A); and (4) a calculating task on a VDT with luminance of 20 cd m(-2) with city noise of 70 dB(A). A visual reaction test (VRT) was performed, and critical flicker fusion frequency (CFF), heart rate (HR), numbers of circulating white blood cells (WBCs), lymphocyte subsets and subjective symptoms of fatigue were measured (1) before; (2) just after; and (3) 30 min after each 60 min test. Subjective symptoms of fatigue significantly increased just after experiments conducted under the two noisy conditions. VRT and CFF showed significant changes in the case of the high-luminance display with noise. WBCs and neutrophils showed significant increases in the two quiet conditions. These results suggested that high luminance with noise had the most effect on subjective fatigue and mental activities.