No differences were found between daytime high- and low-noise-exposed workers in relation to self-reported sleep variables, including insomnia and excessive daytime sleepiness.
High-noise-exposed metal industrial workers had a mean Bergen Insomnia Scale score of 13.2, with 40.3% reporting insomnia and 39.8% reporting excessive daytime sleepiness.
Low-noise-exposed office cleaners had a mean Bergen Insomnia Scale score of 15.4, with 51.4% reporting insomnia and 41.7% reporting excessive daytime sleepiness.
The crude odds ratio for insomnia among high-noise-exposed workers compared to low-noise-exposed workers was not statistically significant.
After adjusting for potential confounders, insomnia and daytime sleepiness did not differ significantly between high- and low-noise-exposed groups.
The study used a cross-sectional design with interview-based questionnaires among workers in Tanzania, where workplaces often have high noise levels.
This research suggests that workers exposed to very high levels of workplace noise (nearly 98 decibels on average, typical of metal industries) do not report significantly worse sleep outcomes compared to workers exposed to lower noise levels (about 77 decibels, typical of office cleaning). The study, conducted in Tanzania, measured insomnia and daytime sleepiness using standardized questionnaires among 253 workers. Surprisingly, the low-noise group actually reported slightly higher rates of insomnia (51.4%) than the high-noise group (40.3%), though this difference was not statistically significant once other factors were taken into account. Both groups showed notably high rates of sleep problems overall — roughly 40–50% reported insomnia and around 40% reported excessive daytime sleepiness — suggesting that sleep difficulties are widespread among these workers regardless of noise exposure level. This finding points to the importance of other factors, such as age, lifestyle habits, and working conditions beyond noise, in shaping sleep quality in this population. This research matters because it challenges the assumption that daytime occupational noise exposure is a straightforward driver of poor sleep, at least as measured by self-report. The authors caution that the cross-sectional design and reliance on self-reported data limit firm conclusions, and that unmeasured factors could be influencing the results. Future studies using objective sleep measures and longitudinal designs would help clarify the relationship between occupational noise and sleep health, particularly in lower-income countries where workers may face especially high noise exposures.
Axwesso W, Sakwari G, Nyarubeli I, Moen B, Pallesen S, Mamuya S. (2026). Relationship Between Workplace Noise Exposure and Sleep in Tanzania.. Noise & health. https://doi.org/10.4103/nah.nah_107_25