The effects of cleanroom noise intensity and frequency on physiological measures and subjective responses

Impacts of noise-induced hearing loss on sleep, health, and workplace: Multi-group analysis

Noise-induced hearing loss (NIHL) is a significant occupational health concern, particularly in industries with high levels of noise exposure. This study examines the effects of NIHL on sleep quality, daily life health conditions, and workplace health problems among workers. A total of 1285 workers participated in the study, and the data were analyzed using partial least squares structural equation modeling (PLS-SEM) to assess the impacts of NIHL. The analysis included a multi-group analysis to differentiate the effects between workers who wear noise protection and those who do not. Our findings indicate that NIHL significantly affects sleep quality, with a coefficient of 0.263 (t = 9.957, p<0.001), daily life health conditions with a coefficient of 0.296 (t = 10.793, p<0.001), and workplace health problems with a coefficient of 0.345 (t = 13.814, p<0.001). The multi-group analysis revealed more severe impacts on sleep and health in the non-wearing group compared to the noise-protection-wearing group, with statistically significant differences in path coefficients for sleep disorders (-0.033), health problems in daily life (-0.184), and health problems in the workplace (-0.190), all showing p-values of 0.000. These results underscore the detrimental effects of NIHL on multiple aspects of workers' health and emphasize the importance of wearing noise protection to mitigate these effects. This study provides vital insights for both researchers and practitioners in public health, suggesting that improved noise protection strategies are essential for protecting workers in noisy environments.

Students' blood pressure and heart rate while performing cognitive tasks at education institutions in Northern and Northeastern Brazil

BACKGROUND

The use of information and communication technologies improves the versatility of learning environments by broadening the scope of educational practices, allowing students to communicate with other institutions and providing access to information in real time. However, these tools, in addition to environmental characteristics, can increase the internal thermal load, which is directly influenced by the external environment, with a consequent impact on body physiology.

OBJECTIVE

The present study investigated the relationship between air temperature and blood pressure and heart rate among students performing cognitive tasks at computer laboratories in four public universities (three in Northeastern Brazil and one in Northern Brazilian).

METHODS

Thermal conditions and physiological parameters were analysed over three consecutive days, and the participants were subjected to changes in air temperature from 20°C to 33°C. Blood pressure and heart rate were measured before and after testing.

RESULTS

Analyses of the experimental data showed changes in heart rate at high temperatures, with a greater risk of students from Teresina and Manaus institutions presenting heart rates above 100 bpm during cognitive tasks.

CONCLUSIONS

Within the temperature range applied, on the day of the highest temperature, we observed the highest percentage of participants who reported thermal discomfort (63%, 33°C; 58%, 29°C; 38%, 28°C) and a reduction of cognitive performance (15 to 10 points when the air temperature increases from 20 to 33°C).

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.