Effects of Long-Term Noise Exposure on Mental Health and Sleep Quality of Emergency Medical Staff and Coping Strategies

Abstract

Objective:

This study aimed to explore the effects of long-term noise exposure on the mental health and sleep quality of medical staff in an emergency department and noise-coping strategies.

Methods:

In this cross-sectional study, 126 emergency medical staff (49 doctors and 77 nurses) and 100 medical staff (40 doctors and 60 nurses) from the general inpatient department of two hospitals in China were selected as subjects. The research period was from January to October 2024. The daytime and night-time noise levels in the emergency department and general inpatient department were collected. The Symptom Checklist-90 (SCL-90) was used to assess the mental health status. The Pittsburgh Sleep Quality Index (PSQI) and polysomnography were used to evaluate sleep quality. Pearson correlation analysis was used to evaluate the correlation amongst variables.

Results:

The daytime and night-time noise-exposure levels in the emergency department were significantly higher than those in the general inpatient department (P < 0.05). The scores for somatisation, obsessive–compulsive symptoms, depression, anxiety, hostility, terror, psychoticism, PSQI and SCL-90 in the emergency department were higher than those in the general inpatient department (P < 0.05). The sleep duration and sleep efficiency of medical staff in the emergency department were significantly lower than those in the general inpatient department. The sleep latency time and awakening time were significantly higher than those in the general inpatient department (P < 0.05). Pearson correlation analysis showed that daytime noise-exposure level was positively correlated with the SCL-90 total score (r = 0.326, P < 0.001) and total PSQI score (r = 0.298, P = 0.021). Meanwhile, the night-time noise-exposure level was positively correlated with the SCL-90 total score (r = 0.435, P < 0.001), PSQI total score (r = 0.515, P < 0.001), sleep latency time (r = 0.422, P<0.001) and awakening time of emergency medical staff (r = 0.261, P < 0.001). Night-time noise exposure had negative correlations with sleep duration (r = −0.503, P < 0.001) and sleep efficiency (r = −0.293, P < 0.001).

KEY MESSAGES

• (1)Noise-exposure levels in the emergency department were significantly higher than those in the general inpatient department.
• (2)Long-term noise exposure negatively affected emergency medical staff’s mental health, and noise levels were positively correlated with the Symptom Checklist-90 scores.
• (3)Long-term noise exposure also affected the sleep quality of emergency medical staff.
• (4)Coping strategies like environmental renovation and staff-support systems may help enhance the mental well-being of emergency medical staff.

INTRODUCTION

Emergency medical staffs are an important part of the medical system. They perform increasingly heavy medical treatment, prevention and control tasks. They face high-intensity physical load and also bear huge psychological pressure. Long-term noise exposure, as a common phenomenon in the working environment of emergency medical staff, is gradually attracting people’s attention.[1,2]

Noise, an invisible and colourless environmental factor, can unknowingly affect people’s physical and mental health. The World Health Organization points out that noise can cause physiological and psychological stress on human; it suggests that average hospital sound levels should not exceed 35 dB with a maximum of 40 dB overnight.[3] Long-term noise exposure can lead to tinnitus; increased blood pressure; vasoconstriction; muscle tension; and even anxiety, irritability, headache, insomnia and other symptoms.[4,5] For instance, Tang et al.[6] reported that noise in the emergency department significantly contributes to occupational burnout and resignation intention amongst medical staff. Similarly, Hendriks et al.[2] found that reduced noise levels in the emergency department positively affect staff well-being and room acoustic environment. In the traditional emergency department, the ambient noise level can reach up to 80 dB during the day and 60 dB at night,[7] constituting a unique ‘work symphony’ to the emergency medical staff. Long-term noise exposure affects the work efficiency and concentration of medical staff and may also have a serious impact on their mental health. Additionally, noise can interfere with sleep, causing sleep disorders such as difficulty falling asleep, light sleep, early awakening and dreaminess. In turn, they affect the body’s self-repair mechanism, reduce immunity and increase the risk of disease.[8] The present study aimed to explore the specific impact of long-term noise exposure on the mental health and sleep quality of emergency medical staff and proposes corresponding coping strategies.

MATERIALS AND METHODS

General information

In this cross-sectional study from January to October 2024, 126 emergency medical staff (49 doctors and 77 nurses) and 100 medical staff (40 doctors and 60 nurses) from the general inpatient department of the Zhoukou Hospital of Traditional Chinese Medicine and Zhoukou Maternal and Child Health Hospital were selected as subjects. Zhoukou Hospital of Traditional Chinese Medicine is a comprehensive hospital integrating traditional Chinese medicine and modern medicine, whereas Zhoukou Maternal and Child Health Hospital specialises in paediatric medicine. Selecting samples from two different hospitals provided a comprehensive understanding of the effects of long-term noise exposure on emergency medical staff.

The inclusion criteria were as follows: (1) worked in the current department for more than 1 year, during which the noise level was relatively stable; (2) had no serious mental illness or primary insomnia and (3) fully understood the research purpose, process, potential risks and benefits and voluntarily signed an informed consent form.

The exclusion criteria were as follows: (1) had recently (within the past 6 months) experienced major life events (such as death of a family member or serious illness, divorce or other major stressors) that may have significantly affected their mental health and sleep quality; and (2) had hearing impairment.

Observation indicators

Noise monitoring

Ambient noise in the emergency department and general inpatient department was continuously monitored using 2270-S sound level meters produced by Brüel & Kjær, Denmark. This sound level meter has a measurement frequency range of 20 Hz–20 kHz and an accuracy of ±1.4 dB.

The sound level meters in the emergency department were placed as follows: two sound level meters were installed in each of the entrance area, ambulance parking area and corridors, and 1.5–1.8 m above the ground and away from the corner of the walls. One sound level meter was installed in each of the reception, triage area, waiting area, trauma treatment room, laboratory and medicine-preparation room at a height of 1.2–1.5 m above the ground away from any noisy equipment. The nurse station and patient observation room each had one sound level meter located 0.8–1 m above the ground and 0.5 m from the surrounding walls. The results from all these sound level meters were averaged to represent the overall noise-exposure level in the emergency department.

In the general inpatient department, the monitoring points were adjusted based on the layout. One sound level meter was installed at the nurse station, and 1–2 sound level meters were installed in each ward. In the corridors, one sound level meter was installed every 20 m. The height of sound level meters was similar to those in the emergency department. The data from these sound level meters were also averaged to obtain the overall noise level in the general inpatient department.

Environmental noise was monitored 24 h a day. The daytime interval was from 06:00 to 22:00, and the night-time interval was from 22:00 to 06:00.

Mental health

Mental-health status was assessed using the Symptom Checklist-90 Revised (SCL-90-R). It contains 90 items across the following 10 dimensions: somatisation, obsessive–compulsive symptoms, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism and additional general symptoms. Each item is rated on a five-point Likert scale, where ‘0’ represents ‘not at all’, ‘1’ represents ‘a little’, ‘2’ represents ‘moderately’, ‘3’ represents ‘quite a bit’ and ‘4’ represents ‘extremely’. In this study, we used the Global Severity Index (GSI) of the SCL-90-R to reflect the overall level of psychological distress. The GSI is calculated by summing up the scores of all items and then dividing by the number of items actually answered. As a result, the GSI score can range from 0 (indicating no psychological distress) to 4 (indicating severe psychological distress). The Cronbach’s alpha of SCL-90-R is often reported to be above 0.90.[9]

Sleep quality

(1) The Pittsburgh Sleep Quality Index (PSQI)[10] was used to measure subjective sleep quality. PSQI consists of 19 items and is divided into seven components, including subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbances, use of sleeping medications and daytime dysfunction. Each component has a score ranging from 0 to 3, and a total score ranging from 0 to 21. A higher total score indicates poorer sleep quality. The internal consistency coefficient of the PSQI is 0.84, and the test–retest reliability is 0.81.

(2) Polysomnography monitoring: A Philips Alice 6 LDx polysomnography system (Philips Respironics, USA) was used to record the sleep structure parameters of subjects at night. Monitoring was conducted continuously from 22:00 to 06:00 for three consecutive nights for each subject. This specific time period was chosen to comprehensively capture the sleep patterns during the typical night rest time. Monitoring for three nights helped reduce the impact of random factors on sleep quality, ensuring more reliable and representative data. Sleep efficiency = sleep time/total time in bed × 100%. A sleep efficiency of ≥85% is considered to be normal. Compared with PSQI, polysomnography, as the gold standard for sleep assessment, provides an objective and continuous record of sleep patterns, reducing the influence of recall bias and social desirability bias.

Statistical methods

SPSS 24.0 (IBM Corporation, Armonk, NY, USA) was used for statistical analysis. The continuous data in accordance with the normal distribution were expressed as mean ± standard deviation (¯x ± s) and compared by t-tests. Categorical data were expressed as [n (%)] and tested by chi-square (χ²) tests. P < 0.05 was considered to be statistically significant. Pearson analysis was used to determine the correlation between noise exposure and health outcomes. Specifically, when |r| > 0.2 (approximately, depending on sample size and test strictness), P < 0.05; when |r| > 0.3 (approximately), P < 0.01.

RESULTS

General information

The basic demographic characteristics of the emergency department and the general inpatient department were comparable, with no significant difference (P > 0.05), as shown in Table 1.

Table 1.

General information in the emergency and general inpatient departments [n (%)]

General information		General inpatient department doctor (n = 40)	Emergency doctor (n = 49)	χ 2	P	General inpatient department nurse (n = 60)	Emergency nurse (n = 77)	χ 2	P
Age (year)	<31	8 (20.00)	10 (20.41)	2.239	0.326	28 (46.67)	32 (41.56)	0.358	0.836
	31–40	18 (45.00)	15 (30.61)			22 (36.67)	31 (40.26)
	>40	14 (35.00)	24 (48.98)			10 (16.67)	14 (18.18)
Gender	Male	29 (72.50)	30 (61.22)	1.253	0.263	15 (25.00)	30 (38.96)	2.980	0.084
	Female	11 (27.50)	19 (38.78)			45 (75.00)	47 (61.04)
Marital status	Married	22 (55.00)	25 (51.02)	0.886	0.642	27 (45.00)	40 (51.95)	0.893	0.640
	Unmarried	13 (32.50)	20 (40.82)			29 (48.33)	31 (40.26)
	Divorce	5 (12.50)	4 (8.16)			4 (6.67)	6 (7.79)
Education level	Undergraduate and below	5 (12.50)	7 (14.29)	0.146	0.930	46 (76.67)	59 (76.62)	0.083	0.95
	Master	18 (45.00)	23 (46.94)			10 (16.67)	12 (15.58)
	Doctor	17 (42.50)	19 (38.78)			4 (6.67)	6 (7.79)
Professional title	Chief/Associate chief	7 (17.50)	10 (20.41)	1.754	0.625	8 (13.33)	12 (15.58)	0.701	0.873
	Intermediate	16 (40.00)	23 (46.94)			14 (23.33)	14 (18.18)
	Primary	14 (35.00)	11 (22.45)			28 (46.67)	36 (46.75)
	Other	3 (7.50)	5 (10.20)			10 (16.67)	15 (19.48)
Length of service (years)	≤10 years	18 (45.00)	29 (59.18)	1.778	0.182	38 (63.33)	52 (67.53)	0.264	0.607
	>10 years	22 (55.00)	20 (40.82)			22 (36.67)	25 (32.47)
Weekly working time (h)	<41	12 (30.00)	12 (24.49)	1.329	0.514	14 (23.33)	20 (25.97)	0.524	0.769
	41–60	20 (50.00)	22 (44.90)			31 (51.67)	35 (45.45)
	>60	8 (20.00)	15 (30.61)			15 (25.00)	22 (28.57)

Noise-exposure levels

The daytime and night noise-exposure levels in the emergency department were significantly higher than those in the general inpatient department (P < 0.05), as shown in Table 2.

Table 2.

Comparison of noise-exposure levels between the emergency department and general inpatient department (dB, ± s)

Department	Daytime noise level	Night noise level
Emergency department	72.42 ± 3.89	59.33 ± 4.87
General inpatient department	65.26 ± 3.57	46.34 ± 4.02
t	14.249	21.487
P	<0.001	<0.001

SCL-90 scores

The scores of somatisation, obsessive–compulsive, depression, anxiety, hostility, phobic anxiety, psychoticism and the GSI of the emergency medical staff in the emergency department were higher than those of the medical staff in the general inpatient department (P < 0.05). No difference in the interpersonal sensitivity and paranoid ideation scores existed between the two departments (P > 0.05), as shown in Table 3.

Table 3.

Comparison of SCL-90 scores between the emergency and general inpatient departments ( ± s)

SCL-90 dimension	Emergency department (n = 126)	General inpatient department (n = 100)	t	P
Somatization	1.82 ± 0.43	1.48 ± 0.49	5.549	<0.001
Obsessive-compulsive	1.98 ± 0.50	1.72 ± 0.40	4.234	<0.001
Interpersonal sensitivity	1.70 ± 0.35	1.73 ± 0.43	0.579	0.564
Depression	1.77 ± 0.35	1.62 ± 0.43	2.891	0.004
Anxiety	1.73 ± 0.30	1.63 ± 0.44	2.026	0.044
Hostility	1.84 ± 0.42	1.72 ± 0.37	2.248	0.026
Phobic anxiety	1.58 ± 0.32	1.33 ± 0.32	5.833	<0.001
Paranoid ideation	1.53 ± 0.30	1.42 ± 0.28	2.819	0.005
Psychoticism	1.67 ± 0.40	1.40 ± 0.23	6.006	<0.001
GSI	1.74 ± 0.37	1.56 ± 0.38	3.589	<0.001

Notes: GSI, Global Severity Index; SCL-90, the Symptom Checklist-90.

PSQI scores

The scores of all seven components and total scores of PSQI score of emergency medical staff in the emergency department were higher than those of medical staff in the general inpatient department (P < 0.05), as shown in Table 4.

Table 4.

Comparison of PSQI scores between the emergency and general inpatient departments ( ± s)

PSQI component	Emergency department (n = 126)	General inpatient department (n = 100)	t	P
Subjective sleep quality	1.52 ± 0.48	0.83 ± 0.22	13.304	<0.001
Sleep latency	1.62 ± 0.43	0.87 ± 0.21	15.980	<0.001
Sleep duration	1.70 ± 0.55	1.21 ± 0.36	7.695	<0.001
Sleep efficiency	0.89 ± 0.22	0.65 ± 0.15	9.322	<0.001
Sleep disturbances	1.11 ± 0.32	0.73 ± 0.19	10.495	<0.001
Use of sleeping medications	1.28 ± 0.35	0.70 ± 0.23	14.298	<0.001
Daytime dysfunction	0.95 ± 0.19	0.68 ± 0.20	10.366	<0.001
Total score	9.07 ± 1.38	5.67 ± 1.38	18.396	<0.001

Note: PSQI, the Pittsburgh Sleep Quality Index.

Polysomnography parameters

The total sleep duration and sleep efficiency of the emergency department were significantly shorter than those of the general inpatient department. The sleep latency and awakening time were significantly longer than those in the general inpatient department (P < 0.05), as shown in Table 5.

Table 5.

Comparison of polysomnography parameters between the emergency and general inpatient departments ( ± s)

Polysomnography parameter	Emergency department (n = 126)	General inpatient department (n = 100)	t	P
Total sleep duration (min)	326.43 ± 51.36	405.47 ± 51.13	11.514	<0.001
Sleep latency (min)	37.35 ± 10.45	21.25 ± 6.76	13.346	<0.001
Awakening time (min)	66.42 ± 20.05	48.30 ± 10.41	8.195	<0.001
Sleep efficiency (%)	72.36 ± 7.19	78.65 ± 6.84	6.674	<0.001

Correlation analysis

Correlation analysis showed positive correlations between daytime noise exposure and the total scores of GSI (r = 0.326, P < 0.001) and PSQI (r = 0.298, P = 0.021). The correlation between night-time noise exposure and the GSI (r = 0.435, P < 0.001) and PSQI (r = 0.515, P < 0.001) were higher than in daytime.

Night-time noise exposure was positively correlated with sleep latency (r = 0.422, P < 0.001) and awakening time (r = 0.261, P < 0.001). Conversely, the negative correlation of night-time noise exposure with sleep duration (r = −0.503, P < 0.001) and sleep efficiency (r = −0.293, P < 0.001) further emphasised the detrimental effects of noise on sleep. Details are shown in Table 6.

Table 6.

Correlations between noise exposure level and health outcomes of the emergency and general inpatient departments.

Health outcome	Daytime noise-exposure level		Night noise-exposure level
	r	P	r	P
GSI	0.326	<0.001	0.435	<0.001
PSQI total score	0.298	0.021	0.515	<0.001
Sleep duration*	−0.138	0.200	−0.503	<0.001
Sleep latency*	0.192	0.141	0.422	<0.001
Awakening time*	0.092	0.484	0.261	<0.001
Sleep efficiency*	−0.196	0.134	−0.293	<0.001

Notes: GSI, Global Severity Index in the Symptom Checklist-90; PSQI, the Pittsburgh Sleep Quality Index; *Polysomnography parameters.

DISCUSSION

Medical staffs in the emergency department face a high-intensity and high-stress work environment in which long-term noise exposure is a problem that cannot be ignored.[11] The sound of ambulance sirens, noisy equipment in the emergency room and intense work exchanges continue to affect their physical and mental health. For instance, Yang et al.[12] suggested that high-noise levels and staff-related activities affect the sleep quality of conscious patients in the emergency intensive care unit. Targeted measures can improve the prognoses of patients. Research has found that high-noise exposure is significantly correlated with lower occupational quality of life. Specifically, nurses exposed to high-noise report more health problems, higher levels of stress and fatigue and fewer supportive environments than those with low-noise exposure.[13] These studies, along with our findings, suggest that noise-induced stress and impaired sleep quality exist amongst medical staff in different healthcare settings.

In the current study, the day and night noise levels in the emergency department were significantly higher than those in the general inpatient department. The emergency department is one of the busiest departments in the hospital, dealing with a large number of emergency patients every day. Consequently, the personnel turnover is high, and equipment alarms and communications are frequent amongst medical staff. Together, these factors considerably increase the noise level in the emergency department compared with that in general wards. Specifically, the frequent entry and exit of ambulances can generate high-decibel alarm sounds, and various medical equipment (such as ventilators and monitors) in the emergency room also produce sustained noise during operation. To quickly and accurately communicate patient conditions and treatment plans in noisy environments, medical staff often need to raise their voices, further exacerbating the noise level. Long-term noise exposure activates the hypothalamus–pituitary–adrenal axis, resulting in the sustained elevation of stress hormones such as cortisol. In turn, anxiety, depression and other psychological symptoms are triggered.[14] The unpredictability and high intensity of emergency department noise sources (e.g., sirens, equipment noise and patient calls) may exacerbate this physiological response. Elevated somatisation scores of the SCL-90 (e.g., fatigue and headache) may be associated with immune and metabolic disturbances owing to chronic sleep deprivation. Noise at night interferes with sleep architecture (e.g., shortening the period of deep sleep), further amplifying somatisation symptoms.[15] However, no significant difference in interpersonal sensitivity and paranoid ideation scores of the SCL-90 existed between the emergency and general inpatient departments. The reason may be that both types of symptoms were more related to social support or individual cognitive patterns. Emergency medical staff may experience high work pressure, but they often have strong teamwork and communication skills. Thus, their interpersonal sensitivity may not be worse than that of medical staff in a general inpatient department. The paranoid ideation factor primarily assesses the extent to which individuals are distrustful and suspicious of others. The work nature of emergency medical staff requires them to trust their team members and work together to cope with emergencies.[16] Therefore, emergency medical staff may not exhibit significantly higher levels of paranoid ideation than medical staff of general inpatient department.

The positive correlation between daytime noise exposure and the GSI of SCL-90 (r = 0.326, P < 0.001) and PSQI (r = 0.298, P = 0.021) indicated that higher daytime noise levels were associated with poorer overall mental health and sleep quality. A stronger positive correlation existed between night-time noise exposure and the GSI (r = 0.435, P < 0.001) and PSQI (r = 0.515, P < 0.001). Studies have shown that night-time noise has a more significant impact on mental health and sleep quality because night-time noise interferes with circadian rhythms by suppressing melatonin secretion, leading to prolonged sleep latency and decreased sleep efficiency.[17] The frequency of night-time emergencies may further exacerbate this disturbance. Noise triggers increased alertness by activating the brain’s reticular activating system and amygdala, leading to frequent night-time awakenings. Prolonged wakefulness can lead to chronic fatigue and impaired daytime functioning. Sleep inefficiency may exacerbate symptoms such as anxiety and depression by reducing functional connectivity in the prefrontal cortex and impairing emotion regulation. Results also showed a positive correlation of night-time noise exposure with sleep latency (r = 0.422, P < 0.001) and awakening time (r = 0.261, P < 0.001), as well as a negative correlation of night-time noise exposure with sleep duration (r = −0.503, P < 0.001) and sleep efficiency (r = −0.293, P < 0.001). Noise may affect sleep quality through several mechanisms. Firstly, it can disrupt sleep by causing autonomic nervous system imbalance, leading to increased heart rate and blood pressure and decreased sleep quality. Secondly, it may exacerbate somatisation symptoms and mental-health problems via inflammatory factor-mediated pathological pathways. Thirdly, the high-risk and uncertainty of emergency patients can exacerbate the obsessive–compulsive symptoms and hostility of medical staff. Noise-reducing interventions can also alter workload, physical complaints, productivity and room acoustics.

Coping strategies for noise exposure

Our findings underscored the urgent need for effective noise-control measures in emergency departments. The main coping strategies for noise exposure in the emergency department include the following aspects: (1) for environmental and equipment improvements, optimise the emergency room layout, concentrate high-noise equipment or use of soundproof covers and choose/maintain low-noise equipment.[18,19,20] (2) In staff management and workflow, develop communication standards to reduce shouting and confusion, enhance team collaboration training and optimise scheduling to ensure rest and reasonable manpower allocation, avoiding prolonged noise exposure. (3) Construct a psychological and health-support system by providing mental-health education, counselling and a counselling room. (4) Focus on sleep health through personalized plans, restrooms with napping facilities and sleep hygiene training.

Limitations

Additionally, we focused only on noise exposure, neglecting other factors like personal characteristics, work stress and family support, which future research should consider. Additionally, although the noise monitoring in this study took into account various areas of the emergency department, the limited monitoring points may not fully represent the noise environment. Nevertheless, this work provided valuable data on noise-exposure levels and enabled a quantitative assessment of its impact on mental health and sleep quality.

CONCLUSION

Long-term noise exposure had significant negative impacts on the mental health and sleep quality of emergency medical staff. Effective noise-control strategies should be adopted to protect the physical and mental health of emergency medical staff and thus improve the quality and efficiency of emergency medical services.

Conflicts of interest

The authors declare no conflicts of interest.

Availability of data and materials

The datasets generated and/or analysed during the current study are available from the corresponding author (Ya Liu) upon reasonable request.

Authors contributions

Dong Ren: conceptualization, methodology, original draft, experimental studies, editing, project administration.

Ya Liu: data curation, experimental studies, literature search, writing, editing, formal analysis, supervision.

Lingfeng Xu: original draft, experimental studies, supervision.

Ethics approval and consent to participate

Zhoukou Hospital of Traditional Chinese Medicine (approval number: JJ ume-A-2023-2749) and Zhoukou Maternal and Child Health Hospital (approval number: XM20230806). Informed consent was obtained from all participants.

Funding Statement

Nil.